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Page 1: A Tracked Vehicle

A tracked vehicle (also called: track-type tractor, tractor crawler, or track-laying vehicle) is a vehicle that runs on continuous tracks instead of wheels. Tracked vehicles include construction vehicles, military armored vehicles and unmanned ground vehicles.

The principal design advantages of tracked over wheeled vehicles are that they are in contact with a larger surface area than would generally be the case with a wheeled vehicle, and as a result exert a much lower force per unit area on the ground being traversed than a conventional wheeled vehicle of the same weight. This makes them suitable for use on soft, low friction and uneven ground such as mud, ice and snow. The principal disadvantage is that tracks are a more complex mechanism than a wheel, and relatively prone to failure modes such as snapped or derailed tracks.

Contents [hide] 

Fate of pioneer companies

Lombard gasoline production was more limited as they never managed to diversify use away from log hauling; it is believed a diesel built in 1934 was their last unit.

Phoenix, of Eau Claire, Wisconsin, appears to have built at least one gasoline powered machine before fading into history.[citation needed]

Holt and Best ended up merging. Holt had registered the trademark "Caterpillar". The merged company produced a version of the Best 60 tractor, which later became the Caterpillar 60. The new corporation took the name Caterpillar Inc. in approximately 1925, and remains in business today.

[edit] Current manufacturers

For certain tasks, such as soil preparation and maintenance on very steep slopes, crawler tractors are still used. A notable example is vineyards, e.g. in Italy.[9] Today, the pioneer manufacturers have been replaced mostly by large tractor companies such as John Deere, New Holland, Kubota,[10] Case, Caterpillar Inc., CLAAS.[11] Also, there are some crawler tractor companies specialising in niche markets. Examples are Otter Mfg. Co. and Struck Corporation.[12]

A cultivator is any of several types of farm implement used for secondary tillage. One sense of the name refers to frames with teeth (also called shanks) that pierce the soil as they are dragged through it linearly. Another sense refers to machines that use rotary motion of disks or teeth to accomplish a similar result. The rotary tiller is a principal example.

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Cultivators stir and pulverize the soil, either before planting (to aerate the soil and prepare a smooth, loose seedbed) or after the crop has begun growing (to kill weeds—controlled disturbance of the topsoil close to the crop plants kills the surrounding weeds by uprooting them, burying their leaves to disrupt their photosynthesis, or a combination of both). Unlike a harrow, which disturbs the entire surface of the soil, cultivators are designed to disturb the soil in careful patterns, sparing the crop plants but disrupting the weeds.

Cultivators of the toothed type are often similar in form to chisel plows, but their goals are different. Cultivator teeth work near the surface, usually for weed control, whereas chisel plow shanks work deep beneath the surface, breaking up hardpan. Consequently, cultivating also takes much less power per shank than does chisel plowing.

Small toothed cultivators pushed or pulled by a single person are used as garden tools for small-scale gardening, such as for the household's own use or for small market gardens. Similarly sized rotary tillers combine the functions of harrow and cultivator into one multipurpose machine.

Cultivators are usually either self-propelled or drawn as an attachment behind either a two-wheel tractor or four-wheel tractor. For two-wheel tractors they are usually rigidly fixed and powered via couplings to the tractors' transmission. For four-wheel tractors they are usually attached by means of a three-point hitch and driven by a power take-off (PTO). Drawbar hookup is also still commonly used worldwide. Draft-animal power is sometimes still used today, being somewhat common in developing nations although rare in more industrialized economies.

Garden cultivatorsSmall tilling equipment, used in small gardens such as household gardens and small commercial gardens, can provide both primary and secondary tillage. For example, a rotary tiller does both the "plowing" and the "harrowing", preparing a smooth, loose seedbed. It does not provide the row-wise weed control that cultivator teeth would. For that task, there are single-person-pushable toothed cultivators.

[edit] Variants and trademarks

A Japanese two-wheel tractor

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Rotary tillers are popular with home gardeners who want large vegetable gardens. The garden may be tilled a few times before planting each crop. Rotary tillers may be rented from tool rental centers for single-use applications, such as when planting grass.

A small rotary hoe for domestic gardens was known by the trademark Rototiller and another, made by the Howard Group, who produced a range of rotary tillers, was known as the Rotavator.

Rototiller

The small rototiller is typically propelled forward via a (1–5 horsepower or 0.8–3.5 kilowatts) petrol engine rotating the tines, and do not have powered wheels, though they may have small transport/level control wheel(s). To keep the machine from moving forward too fast, an adjustable tine is usually fixed just behind the blades so that through friction with deeper un-tilled soil, it acts as a brake, slowing the machine and allowing it to pulverize the soils. The slower a rototiller moves forward, the more soil tilth can be obtained. The operator can control the amount of friction/braking action by raising and lowering the handlebars of the tiller. Rototillers do not have a reverse as such backwards movement towards the operator could cause serious injury. While operating, the rototiller can be pulled backwards to go over areas that were not pulverized enough, but care must be taken to ensure that the operator does not stumble and pull the rototiller on top of himself. Rototilling is much faster than manual tilling, but notoriously difficult to handle and exhausting work, especially in the heavier and higher horsepower models. If the rototiller's blades catch on unseen subsurface objects, such as tree roots and buried garbage, it can cause the rototiller to abruptly and violently move in any direction.

Rotavator

Unlike the Rototiller, the self propelled Howard Rotavator is equipped with a gearbox and driven forward, or held back, by its wheels. The gearbox enables the forward speed to be adjusted while the rotational speed of the tines remains constant which enables the operator to easily regulate the extent to which soil is engaged. For a two-wheel tractor rotavator this greatly reduces the workload of the operator as compared to a rototiller. These rotavators are generally more heavy duty, come in higher power (4–18 horsepower or 3–13 kilowatts) with either petrol or diesel engines and can cover much more area per hour. The trademarked word "Rotavator" is one of the longest single-word palindromes in the English language.

Mini tiller

Mini tillers are a new type of small agricultural tillers or cultivators used by farmers or homeowners. These are also known as power tillers or garden tillers. Compact, powerful and, most importantly, inexpensive, these agricultural rotary tillers are providing alternatives to four-wheel tractors and in the small farmers' fields in developing countries are more economical than four-wheel tractors.

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Two-wheel tractor

The higher power "riding" rotavators cross out of the home garden category into farming category, especially in Asia, Africa and South America, capable of preparing 1 hectare of land in 8–10 hours. These are also known as power tillers or walking tractors. Years ago they were considered only useful for rice growing areas, where they were fitted with steel cage-wheels for traction, but now the same are being used in both wetland and dryland farming all over the world. They have multiple functions with related tools for dryland or paddys, pumping, transportation, threshing, ditching, spraying pesticide. They can be used on hills, mountains, in greenhouses and orchards. Diesel designs are more popular in developing countries than gasoline.

Industrial useTo the extent that cultivating is done commercially today (such as in truck farming), it is usually powered by tractors, especially row-crop tractors. Industrial cultivators can vary greatly in size and shape, from 10 feet (3 m) to 80 feet (24 m) wide. Many are equipped with hydraulic wings that fold up to make road travel easier and safer. Different types are used for preparation of fields before planting, and for the control of weeds between row crops. The cultivator may be an implement trailed after the tractor via a drawbar; mounted on the three-point hitch; or mounted on a frame beneath the tractor. They are driven by a power take-off shaft. Generally considered a secondary tillage implement, they are commonly used for primary tillage in lighter soils instead of plowing.

The largest versions are now available in a 6 m (20 ft) width, and require a tractor with an excess of 150 horsepower (110 kW) PTO to drive them.[4]

[edit] Field cultivators

Field cultivators are used to complete tillage operations in many types of arable crop fields. The main function of the field cultivator is to prepare a proper seedbed for the crop to be planted into, to bury crop residue in the soil (helping to warm the soil before planting), to control weeds, and to mix and incorporate the soil to ensure the growing crop has enough water and nutrients to grow well during the growing season. The implement has many shanks mounted on the underside of a metal frame, and small narrow rods at the rear of the machine that smooth out the soil surface for easier travel later when planting. In most field cultivators, one-to-many hydraulic cylinders raise and lower the implement and control its depth.

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[edit] Row crop cultivators

Home made sweep. Notice the inner and outer "sweep" blades.

The main function of the row crop cultivator is weed control between the rows of an established crop. Row crop cultivators are usually raised and lowered by a three-point hitch and the depth is controlled by gauge wheels.

Sometimes referred to as sweep cultivators, these commonly have two center blades that cut weeds from the roots near the base of the crop and turn over soil, while two rear sweeps further outward than the center blades deal with the center of the row, and can be anywhere from 1 to 5 rows wide.[citation needed]

A cultipacker is a piece of agricultural equipment that crushes dirt clods, removes air pockets, and presses down small stones, forming a smooth, firm seedbed. Where seed has been broadcast, the roller gently firms the soil around the seeds, ensuring shallow seed placement and excellent seed-to-soil contact.

The cultipacker differs from the field roller in that it is made up of many sections that form peaks and valleys in the soil where packer has been used.

The term cultipacker is almost exclusively applied to ridged packers, while the term roller may refer to either a smooth or a ridged packer.

A common practice amongst food plotters is to make their own cultipacker using a variety of plans specifically meant for building cultipackers.

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A Cambridge roller-cultipacker.

Plough From Wikipedia, the free encyclopedia

(Redirected from Chisel plow)

Jump to: navigation, search

"Plow" redirects here. For the Canadian soldier, see Edward Chester Plow.

"Plowman" redirects here. For the surname, see Plowman (surname).

"Furrow" redirects here. For other uses, see Furrow (disambiguation).

For other uses, see Plough (disambiguation).

The traditional way: a family works the land with horses and plough

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A plough in action in South Africa. This plough has five non-reversible mouldboards. The fifth, empty furrow on the left will be filled by the first furrow of the next pass.

Ploughing with oxen. A miniature from an early-sixteenth-century manuscript of the Middle English poem God Spede ye Plough, held at the British Museum

The plough (BrE) or plow (AmE; see spelling differences;  /ˈplaʊ/) is a tool (or machine) used in farming for initial cultivation of soil in preparation for sowing seed or planting. It has been a basic instrument for most of recorded history, and represents one of the major advances in agriculture.

The primary purpose of ploughing is to turn over the upper layer of the soil, bringing fresh nutrients to the surface, while burying weeds, the remains of previous crops, and both crop and weed seeds, allowing them to break down. It also aerates the soil, allows it to hold moisture better and provides a seed-free medium for planting an alternate crop. In modern use, a ploughed field is typically left to dry out, and is then harrowed before planting. Modern competitions take place for ploughing enthusiasts like the National Ploughing Championships Ploughs were initially pulled by oxen, and later in many areas by horses (generally draught horses) and mules. In industrialised countries, the first mechanical means of pulling a plough were steam-powered (ploughing engines or steam tractors), but these were gradually superseded by internal-combustion-powered tractors. In the past two decades plough use has reduced in some areas (where soil damage and erosion are problems), in favour of shallower ploughing and other less invasive tillage techniques.

Contents [hide]

1 Etymology 2 Parts 3 History

o 3.1 Hoeing

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o 3.2 Scratch plough o 3.3 Crooked ploughs o 3.4 Mouldboard plough o 3.5 Loy ploughing o 3.6 Heavy ploughs o 3.7 Improved designs o 3.8 Single-sided ploughing o 3.9 Turnwrest plough o 3.10 Reversible plough o 3.11 Riding and multiple-furrow ploughs o 3.12 Steam ploughing o 3.13 Stump-jump plough o 3.14 Modern ploughs

4 Specialist ploughs o 4.1 Chisel plough o 4.2 Ridging plough o 4.3 Scottish hand plough o 4.4 Mole plough

5 Advantages and disadvantages of the mouldboard plough 6 See also 7 Notes 8 References 9 Further reading 10 External links

[edit] EtymologyIn English, as in other Germanic languages, the plough was traditionally known by other names, e.g. Old English sulh, Old High German medela, geiza, or huohili, and Old Norse arðr, all presumably referring to the scratch plough.

The current word plough also comes from Germanic, but it appears relatively late (it is absent from Gothic), and is thought to be a loanword from one of the north Italic languages. In these it had different meanings: in Raetic plaumorati (Pliny), and in Latin plaustrum "wagon, cart", plōstrum, plōstellum "cart", and plōxenum, plōximum "cart box".[1][2]

The name "plough" originates from the Proto-Germanic *plōguz ~ *plōgaz. According to a questionable etymology,[3] the root of that word comes from the PIE stem *blōkó-, in which case it would be cognate to Armenian pelem "to dig" and Welsh bwlch "crack". *Plōguz could actually be borrowed from the Proto-Slavic *plōgu "plough", which gave plugǔ in Old Slavonic.[3][4]

[edit] Parts

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Schema of a contemporary plough

The picture to the right illustrates the basic parts of a contemporary plough (numbering matches parts on the image):

1. Frame2. Three point attach3. Height regulator4. Knife or Coulter (a round rotating disc is often used)5. Chisel6. Share , also called the ploughshare7. Mouldboard8. Plough shaft

Other portions include the frog, runner, land side, shin, trash board and handles.

On modern ploughs and some older ploughs, the mouldboard is separate from the share and runner, allowing these parts to be replaced without replacing the mouldboard. Abrasion eventually destroys all parts of a plough that contact the soil.

[edit] History

Ancient Egyptian plough, circa 1200 B.C.

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Ploughing with buffalo in Hubei, China

[edit] HoeingMain article: Hoe-farming

When agriculture was first developed, simple hand-held digging sticks or hoes would have been used in highly fertile areas, such as the banks of the Nile where the annual flood rejuvenates the soil, to create furrows wherein seeds could be sown. To grow crops regularly in less fertile areas, the soil must be turned to bring nutrients to the surface. The first people known to plough were the Sumerians.

[edit] Scratch ploughMain article: Ard (plough)

The domestication of oxen in Mesopotamia and by its contemporary Indus valley civilization, perhaps as early as the 6th millennium BC, provided mankind with the pulling power necessary to develop the plough. The very earliest plough was the simple scratch-plough, or ard, which consists of a frame holding a vertical wooden stick that was dragged through the topsoil (still used in many parts of the world). It breaks up a strip of land directly along the ploughed path, which can then be planted. Because this form of plough leaves a strip of undisturbed earth between the rows, fields are often cross-ploughed at 90 degree angles, and this tends to lead to squarish fields.[5] In the archaeology of northern Europe, such squarish fields are referred to as "Celtic fields".

A Sokha is an old Russian scratch-plough.

[edit] Crooked ploughsMain article: Aratrum

The Greeks apparently introduced the next major advance in plough design; the crooked plough, which angled the cutting surface forward, leading to the name. The cutting surface was often faced with bronze or (later) iron. Metal was expensive, so in times of war it was melted down or forged to make weapons – or the reverse in more peaceful times.[citation needed] This is presumably the origin of the expression found in the Bible "beat your swords to ploughshares".

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[edit] Mouldboard plough

Water buffalo used for ploughing in Si Phan Don, Laos

A major advance in plough design was the mouldboard plough (American spelling: moldboard plow), which aided the cutting blade. The coulter, knife or skeith cuts vertically into the ground just ahead of the share (or frog) a wedge-shaped surface to the front and bottom of the mouldboard with the landside of the frame supporting the below-ground components. The upper parts of the frame carry (from the front) the coupling for the motive power (horses), the coulter and the landside frame. Depending on the size of the implement, and the number of furrows it is designed to plough at one time, there is a wheel or wheels positioned to support the frame. In the case of a single-furrow plough there is only one wheel at the front and handles at the rear for the ploughman to steer and manoeuvre it.

When dragged through a field the coulter cuts down into the soil and the share cuts horizontally from the previous furrow to the vertical cut. This releases a rectangular strip of sod that is then lifted by the share and carried by the mouldboard up and over, so that the strip of sod (slice of the topsoil) that is being cut lifts and rolls over as the plough moves forward, dropping back to the ground upside down into the furrow and onto the turned soil from the previous run down the field. Each gap in the ground where the soil has been lifted and moved across (usually to the right) is called a furrow. The sod that has been lifted from it rests at about a 45 degree angle in the next-door furrow and lies up the back of the sod from the previous run.

In this way, a series of ploughing runs down a field leaves a row of sods that lie partly in the furrows and partly on the ground lifted earlier. Visually, across the rows, there is the land (unploughed part) on the left, a furrow (half the width of the removed strip of soil) and the removed strip almost upside-down lying on about half of the previous strip of inverted soil, and so on across the field. Each layer of soil and the gutter it came from forms the classic furrow.

The mouldboard plough greatly reduced the amount of time needed to prepare a field, and as a consequence, allowed a farmer to work a larger area of land. In addition, the resulting pattern of low (under the mouldboard) and high (beside it) ridges in the soil forms water channels, allowing the soil to drain. In areas where snow buildup is an issue, this allows the soil to be planted earlier as the snow runoff is drained away more quickly.

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A reconstruction of a mouldboard plough

There are five major parts of a mouldboard plough:

1. Mouldboard2. Share3. Landside4. Frog5. Tailpiece

A runner extending from behind the share to the rear of the plough controls the direction of the plough, because it is held against the bottom land-side corner of the new furrow being formed. The holding force is the weight of the sod, as it is raised and rotated, on the curved surface of the mouldboard. Because of this runner, the mouldboard plough is harder to turn around than the scratch plough, and its introduction brought about a change in the shape of fields – from mostly square fields into longer rectangular "strips" (hence the introduction of the furlong).

An advance on the basic design was the iron[dubious – discuss] ploughshare, a replaceable horizontal cutting surface mounted on the tip of the share. The earliest ploughs with a detachable and replaceable share date from around 1000 BC in the Ancient Near East,[6][dubious – discuss] and the earliest iron ploughshares from ca. 500 BC in China.[7][dubious – discuss] Early mouldboards were basically wedges that sat inside the cut formed by the coulter, turning over the soil to the side. The ploughshare spread the cut horizontally below the surface, so when the mouldboard lifted it, a wider area of soil was turned over. Mouldboards are known in Britain from the late 6th century[8] on.

[edit] Loy ploughingMain article: Loy (spade)

Loy ploughing was a form of manual ploughing which took place in Ireland on very small farms or on very hilly ground, where horses could not work or where farmers could not afford them.[9] It was used up until the 1960s in poorer land.[10] This suited the moist climate of Ireland as the trenches formed by turning in the sods providing drainage. It also allowed the growing of potatoes in bogs as well as on mountain slopes where no other cultivation could take place.[11]

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[edit] Heavy ploughs

Chinese iron plough with curved mouldboard, 1637

In the basic mouldboard plough the depth of the cut is adjusted by lifting against the runner in the furrow, which limited the weight of the plough to what the ploughman could easily lift. This limited the construction to a small amount of wood (although metal edges were possible). These ploughs were fairly fragile, and were not suitable for breaking up the heavier soils of northern Europe. The introduction of wheels to replace the runner allowed the weight of the plough to increase, and in turn allowed the use of a much larger mouldboard faced in metal. These heavy ploughs led to greater food production and eventually a significant population increase around 600 AD.[citation needed]

Before the Han Dynasty (202 BC–220 AD), Chinese ploughs were made almost entirely of wood, except the iron blade of the ploughshare. By the Han period, the entire ploughshare was made of cast iron; these are the first known heavy mouldboard iron ploughs.[12][7]

The Romans achieved the heavy wheeled mouldboard plough in the late 3rd and 4th century AD, when archaeological evidence appears, inter alia, in Roman Britain.[13] The first indisputable appearance after the Roman period is from 643, in a northern Italian document.[14] Old words connected with the heavy plough and its use appear in Slavic, suggesting possible early use in this region.[15] The general adoption of the mouldboard plough in Europe appears to have accompanied the adoption of the three-field system in the later eighth and early ninth centuries, leading to an improvement of the agricultural productivity per unit of land in northern Europe.[16]

Research by the French historian Marc Bloch in medieval French agricultural history showed the existence of names for two different ploughs, "the araire was wheel-less and had to be dragged across the fields, while the charrue was mounted on wheels".[17]

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[edit] Improved designs

'A Champion ploughman', from Australia, circa 1900

The basic plough with coulter, ploughshare and mouldboard remained in use for a millennium. Major changes in design did not become common until the Age of Enlightenment, when there was rapid progress in design. Joseph Foljambe in Rotherham, England, in 1730 used new shapes as the basis for the Rotherham plough, which also covered the mouldboard with iron.[18] Unlike the heavy plough, the Rotherham (or Rotherham swing) plough consisted entirely of the coulter, mouldboard and handles. It was much lighter than conventional designs and became very popular in England. It may have been the first plough to be widely built in factories.

James Small further improved the design. Using mathematical methods he experimented with various designs until he arrived at a shape cast from a single piece of iron, the Scots plough. A single-piece cast iron plough was also developed and patented by Charles Newbold in the United States. This was again improved on by Jethro Wood, a blacksmith of Scipio, New York, who made a three-part Scots Plough that allowed a broken piece to be replaced. In 1837 John Deere introduced the first steel plough; it was so much stronger than iron designs that it was able to work the soil in areas of the US that had previously been considered unsuitable for farming. Improvements on this followed developments in metallurgy; steel coulters and shares with softer iron mouldboards to prevent breakage, the chilled plough which is an early example of surface-hardened steel,[19] and eventually the face of the mouldboard grew strong enough to dispense with the coulter.

[edit] Single-sided ploughing

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Single-sided ploughing in a ploughing match

The first mouldboard ploughs could only turn the soil over in one direction (conventionally always to the right), as dictated by the shape of the mouldboard, and so the field had to be ploughed in long strips, or lands. The plough was usually worked clockwise around each land, ploughing the long sides and being dragged across the short sides without ploughing. The length of the strip was limited by the distance oxen (or later horses) could comfortably work without a rest, and their width by the distance the plough could conveniently be dragged. These distances determined the traditional size of the strips: a furlong, (or "furrow's length", 220 yards (200 m)) by a chain (22 yards (20 m)) – an area of one acre (about 0.4 hectares); this is the origin of the acre. The one-sided action gradually moved soil from the sides to the centre line of the strip. If the strip was in the same place each year, the soil built up into a ridge, creating the ridge and furrow topography still seen in some ancient fields.

[edit] Turnwrest plough

The turnwrest plough allows ploughing to be done to either side. The mouldboard is removable, turning to the right for one furrow, then being moved to the other side of the plough to turn to the left (the coulter and ploughshare are fixed). In this way adjacent furrows can be ploughed in opposite directions, allowing ploughing to proceed continuously along the field and thus avoiding the ridge and furrow topography.

[edit] Reversible plough

A four-furrow reversible plough.

The reversible plough has two mouldboard ploughs mounted back-to-back, one turning to the right, the other to the left. While one is working the land, the other is carried upside-down in the air. At the end of each row, the paired ploughs are turned over, so the other can be used. This returns along the next furrow, again working the field in a consistent direction.

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[edit] Riding and multiple-furrow ploughs

Horse-drawn, two-furrow plough.

Early steel ploughs, like those for thousands of years prior, were walking ploughs, directed by the ploughman holding onto handles on either side of the plough. The steel ploughs were so much easier to draw through the soil that the constant adjustments of the blade to react to roots or clods was no longer necessary, as the plough could easily cut through them. Consequently it was not long after that the first riding ploughs appeared. On these, wheels kept the plough at an adjustable level above the ground, while the ploughman sat on a seat where he would have earlier walked. Direction was now controlled mostly through the draught team, with levers allowing fine adjustments. This led very quickly to riding ploughs with multiple mouldboards, dramatically increasing ploughing performance.

A single draught horse can normally pull a single-furrow plough in clean light soil, but in heavier soils two horses are needed, one walking on the land and one in the furrow. For ploughs with two or more furrows more than two horses are needed and, usually, one or more horses have to walk on the loose ploughed sod—and that makes hard going for them, and the horse treads the newly ploughed land down. It is usual to rest such horses every half hour for about ten minutes.

Heavy volcanic loam soils, such as are found in New Zealand, require the use of four heavy draught horses to pull a double-furrow plough. Where paddocks are more square than long-rectangular it is more economical to have horses four wide in harness than two-by-two ahead, thus one horse is always on the ploughed land (the sod). The limits of strength and endurance of horses made greater than two-furrow ploughs uneconomic to use on one farm.[citation needed]

Amish farmers tend to use a team of about seven horses or mules when spring ploughing and as Amish farmers often help each other plough, teams are sometimes changed at noon. Using this method about 10 acres (40,000 m2) can be ploughed per day in light soils and about 2 acres (8,100 m2) in heavy soils.[citation needed]

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[edit] Steam ploughing

A German balance plough. The left-turning set of shares have just completed a pass, and the right-turning shares are about to enter the ground to return across the field.

Ploughing engine Heumar, made by the Ottomayer company (Germany), used in pairs with a balance plough.Built 1929, 220 PS, 21 tons.

The advent of the mobile steam engine allowed steam power to be applied to ploughing from about 1850. In Europe, soil conditions were often too soft to support the weight of heavy traction engines. Instead, counterbalanced, wheeled ploughs, known as balance ploughs, were drawn by cables across the fields by pairs of ploughing engines which worked along opposite field edges. The balance plough had two sets of ploughs facing each other, arranged so when one was in the ground, the other set was lifted into the air. When pulled in one direction the trailing ploughs were lowered onto the ground by the tension on the cable. When the plough reached the edge of the field, the opposite cable was pulled by the other engine, and the plough tilted (balanced), putting the other set of shares into the ground, and the plough worked back across the field.

One set of ploughs was right-handed, and the other left-handed, allowing continuous ploughing along the field, as with the turnwrest and reversible ploughs. The man credited with the invention

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of the ploughing engine and the associated balance plough, in the mid nineteenth century, was John Fowler, an English agricultural engineer and inventor.[citation needed]

In America the firm soil of the Plains allowed direct pulling with steam tractors, such as the big Case, Reeves or Sawyer-Massey breaking engines. Gang ploughs of up to fourteen bottoms were used. Often these big ploughs were used in regiments of engines, so that in a single field there might be ten steam tractors each drawing a plough. In this way hundreds of acres could be turned over in a day. Only steam engines had the power to draw the big units. When internal combustion engines appeared, they had neither the strength nor the ruggedness compared to the big steam tractors. Only by reducing the number of shares could the work be completed.

[edit] Stump-jump plough

Disc ploughs in Australia, circa 1900

The Stump-jump plough was an Australian invention of the 1870s, designed to cope with the breaking up of new farming land, that contains many tree stumps and rocks that would be very expensive to remove. The plough uses a moveable weight to hold the ploughshare in position. When a tree stump or other obstruction such as a rock is encountered, the ploughshare is thrown upwards, clear of the obstacle, to avoid breaking the plough's harness or linkage; ploughing can be continued when the weight is returned to the earth after the obstacle is passed.

A simpler system, developed later, uses a concave disc (or a pair of them) set at a large angle to the direction of progress, that uses the concave shape to hold the disc into the soil – unless something hard strikes the circumference of the disk, causing it to roll up and over the obstruction. As the arrangement is dragged forward, the sharp edge of the disc cuts the soil, and the concave surface of the rotating disc lifts and throws the soil to the side. It doesn't make as good a job as the mouldboard plough (but this is not considered a disadvantage, because it helps fight the wind erosion), but it does lift and break up the soil (see disc harrow).

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[edit] Modern ploughs

A British woman ploughing on a World War I recruitment poster for the Women's Land Army.

Modern ploughs are usually multiple reversible ploughs, mounted on a tractor via a three-point linkage. These commonly have between two and as many as seven mouldboards – and semi-mounted ploughs (the lifting of which is supplemented by a wheel about half-way along their length) can have as many as eighteen mouldboards. The hydraulic system of the tractor is used to lift and reverse the implement, as well as to adjust furrow width and depth. The ploughman still has to set the draughting linkage from the tractor so that the plough is carried at the proper angle in the soil. This angle and depth can be controlled automatically by modern tractors. As a complement to the rear plough a two or three mouldboards-plough can be mounted on the front of the tractor if it is equipped with front three-point linkage.

[edit] Specialist ploughs[edit] Chisel plough

The chisel plough is a common tool to get deep tillage (prepared land) with limited soil disruption. The main function of this plough is to loosen and aerate the soils while leaving crop residue at the top of the soil. This plough can be used to reduce the effects of compaction and to help break up ploughpan and hardpan. Unlike many other ploughs the chisel will not invert or turn the soil. This characteristic has made it a useful addition to no-till and low-till farming practices which attempt to maximise the erosion-prevention benefits of keeping organic matter and farming residues present on the soil surface through the year. Because of these attributes, the use of a chisel plough is considered by some to be more sustainable than other types of plough, such as the mouldboard plough.

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A modern John Deere 8110 Farm Tractor using a chisel plough. The ploughing tines are at the rear; the refuse-cutting coulters at the front.

Bigham Brother Tomato Tiller

The chisel plough is typically set to run up to a depth of eight to twelve inches (200 to 300 mm). However some models may run much deeper. Each of the individual ploughs, or shanks, are typically set from nine inches (229 mm) to twelve inches (305 mm) apart. Such a plough can encounter significant soil drag, consequently a tractor of sufficient power and good traction is required. When planning to plough with a chisel plough it is important to bear in mind that 10 to 15 horsepower (7 to 11 kW) per shank will be required.

Cultivators are often similar in form to chisel ploughs, but their goals are different. Cultivator teeth work near the surface, usually for weed control, whereas chisel plough shanks work deep beneath the surface. Consequently, cultivating also takes much less power per shank than does chisel ploughing.

[edit] Ridging plough

A ridging plough is used for crops, such as potatoes or scallions, which are grown buried in ridges of soil using a technique called ridging or hilling. A ridging plough has two mouldboards facing away from each other, cutting a deep furrow on each pass, with high ridges either side. The same plough may be used to split the ridges to harvest the crop.

[edit] Scottish hand plough

This is a variety of ridge plough notable in that the blade points towards the operator. It is used solely by human effort rather than with animal or machine assistance, and is pulled backwards by the operator, requiring great physical effort. It is particularly used for second breaking of ground,

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and for potato planting. It is found in Shetland, some western crofts and more rarely Central Scotland. The tool is typically found on small holdings too small or poor to merit use of animals.

[edit] Mole ploughMain article: Subsoiler

The mole plough or subsoiler allows underdrainage to be installed without trenches, or it breaks up deep impermeable soil layers which impede drainage. It is a very deep plough, with a torpedo-shaped or wedge-shaped tip, and a narrow blade connecting this to the body. When dragged through the ground, it leaves a channel deep under the ground, and this acts as a drain. Modern mole ploughs may also bury a flexible perforated plastic drain pipe as they go, making a more permanent drain – or they may be used to lay pipes for water supply or other purposes. Similar machines, so called pipe-and-cable-laying ploughs, are even used under the sea, for the laying of cables, as well as preparing the earth for side-scan sonar[citation needed] in a process used in oil exploration.

[edit] Advantages and disadvantages of the mouldboard ploughAdvantages

Mouldboard ploughing, in cold and temperate climates, no deeper than 20 cm, aerates the soil by loosening it. It incorporates crop residues, solid manures, limestone and commercial fertilizers along with some oxygen. By doing so, it reduces nitrogen losses by volatilization, accelerates mineralization and increases short-term nitrogen availability for transformation of organic matter into humus. It erases wheel tracks and ruts caused by harvesting equipment. It controls many perennial weeds and pushes back the growth of other weeds until the following spring. It accelerates soil warming and water evaporation in spring because of the lesser quantity of residues on the soil surface. It facilitates seeding with a lighter seeder. It controls many enemies of crops (slugs, crane flies, seedcorn maggots-bean seed flies, borers). It increases the number of "soil-eating" earthworms (endogea) but is detrimental to vertical-dwelling earthworms (anecic).

Disadvantages

Ploughing leaves very little crop residue on the surface, which otherwise could reduce both wind and water erosion. Over-ploughing can lead to the formation of hardpan. Typically farmers break up hardpan up with a subsoiler, which acts as a long, sharp knife to slice through the hardened layer of soil deep below the surface. Soil erosion due to improper land and plough utilization is possible. Contour ploughing mitigates soil erosion by ploughing across a slope, along elevation lines. Alternatives to ploughing, such as the no till method, have the potential to actually build soil levels and humus, and may be suitable to smaller, more intensively cultivated plots, and to farming on poor, shallow or degraded soils which will only be further damaged by ploughing.

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Crumbler roller, commonly used to compact soil after it has been loosened by a harrow

Clydesdale horses pulling spike harrows, Murrurundi, NSW, Australia

Primitive (“Orwell’s”) spike harrow (Archeological museum – Alanya, Turkey)

In agriculture, a harrow (often called a set of harrows in a plurale tantum sense) is an implement for breaking up and smoothing out the surface of the soil. In this way it is distinct in its effect from the plough, which is used for deeper tillage. Harrowing is often carried out on fields to follow the rough finish left by ploughing operations. The purpose of this harrowing is generally to break up clods (lumps of soil) and to provide a finer finish, a good tilth or soil structure that is suitable for seedbed use. Such coarser harrowing may also be used to remove

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weeds and to cover seed after sowing. Harrows differ from cultivators in that they disturb the whole surface of the soil, such as to prepare a seedbed, instead of disturbing only narrow trails that skirt crop rows (to kill weeds).

There are four general types of harrows: disc harrow, tine harrow, chain harrow and chain disk harrows. Harrows were originally drawn by draft animals, such as horses, mules, or oxen, or in some times and places by manual labourers. In modern practice they are almost always tractor-mounted implements, either trailed after the tractor by a drawbar or mounted on the three-point hitch.

Contents [hide]

1 Types 2 Historical reference 3 See also 4 References 5 External links

[edit] TypesIn cooler climates the most common types are the disc harrow, the chain harrow, the tine harrow or spike harrow and the spring tine harrow. Chain harrows are often used for lighter work such as levelling the tilth or covering seed, while disc harrows are typically used for heavy work, such as following ploughing to break up the sod. In addition, there are various types of power harrow, in which the cultivators are power-driven from the tractor rather than depending on its forward motion.

Tine harrows are used to refine seed-bed condition before planting, to remove small weeds in growing crops and to loosen the inter-row soils to allow for water to soak into the subsoil. The fourth is a chain disk harrow. Disk attached to chains are pulled at an angle over the ground. These harrows move rapidly across the surface. The chain and disk rotate to stay clean while breaking up the top surface to about 1 inch (3 cm) deep. A smooth seedbed is prepared for planting with one pass.

Chain harrowing may be used on pasture land to spread out dung, and to break up dead material (thatch) in the sward, and similarly in sports-ground maintenance a light chain harrowing is often used to level off the ground after heavy use, to remove and smooth out boot marks and indentations. When used on tilled land in combination with the other two types, chain harrowing rolls the remaining larger clumps of soil to the surface where the weather will break them down and prevent interference with seed germination.

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All four harrow types can be used in one pass to prepare the soil for seeding. It is also common to use any combination of two harrows for a variety of tilling processes. Where harrowing provides a very fine tilth, or the soil is very light so that it might easily be wind-blown, a roller is often added as the last of the set.

Harrows may be of several types and weights, depending on the intended purpose. They almost always consist of a rigid frame to which are attached discs, teeth, linked chains or other means of cultivation, but tine and chain harrows are often only supported by a rigid towing-bar at the front of the set.

In the southern hemisphere the so-called giant discs are a specialised kind of disc harrows that can stand in for a plough in very rough country where a mouldboard plough will not handle the tree-stumps and rocks, and a disc-plough is too slow (because of its limited number of discs). Giant scalloped-edged discs operate in a set, or frame, that is often weighted with concrete or steel blocks to improve penetration of the cutting edges. This sort of cultivation is normally immediately followed by broadcast fertilisation and seeding, rather than drilled or row seeding.

A drag is a heavy harrow.

[edit] Historical referenceIn Europe, harrows were first used in the early Middle Ages.[citation needed]

The following text is taken from the Household Cyclopedia of 1881:

"When employed to reduce a strong obdurate soil, not more than two harrows should be yoked together, because they are apt to ride and tumble upon each other, and thus impede the work, and execute it imperfectly. On rough soils, harrows ought to be driven as fast as the horses can walk; because their effect is in the direct proportion to the degree of velocity with which they are driven. In ordinary cases, and in every case where harrowing is meant for covering the seed, three harrows are the best yoke, because they fill up the ground more effectually and leave fewer vacancies, than when a smaller number is employed. The harrowman's attention, at the seed process, should be constantly directed to prevent these implements from riding upon each other, and to keep them clear of every impediment from stones, lumps of earth, or clods, and quickens or grass roots; for any of these prevents the implement from working with perfection, and causes a mark or trail upon the surface, always unpleasing to the eye, and generally detrimental to the vegetation of the seed. Harrowing is usually given in different directions, first in length, then across, and finally in length as at first. Careful husbandmen study, in the finishing part of the process, to have the harrows drawn in a straight line, without suffering the horses to go in a zigzag manner, and are also attentive that the horses enter fairly upon the ridge, without making a curve at the outset. In some instances, an excess of harrowing has been found very prejudicial to the succeeding crop; but it is always necessary to give so much as to break the furrow, and level the surface, otherwise the operation is imperfectly performed."

George Orwell,[1] as a soldier in 1937 in a Spanish Civil War anti-fascist unit three miles east of Huesca, Aragon, found inside “a derelict hut in no man’s land” a harrow of primitive design:

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"There was a kind of harrow that took one straight back to the later Stone Age. It was made of boards joined together, to about the size of a kitchen table; in the boards hundreds of holes were morticed, and into each hole was jammed a piece of flint which had been chipped into shape exactly as men used to chip them ten thousand years ago."

A subsoiler or mole plough is a tractor mounted implement used to loosen and break up soil at depths below the level of a traditional disk harrow or rototiller. Most tractor mounted cultivation tools will break up and turn over surface soil to a depth of 6" to 8" while a subsoiler will break up and loosen soil to twice those depths. Typically a subsoiler mounted to a Compact Utility Tractor will reach depths of about 12" and typically have only one thin blade with a sharpened tip.

The subsoiler is a tillage tool which will improve growth in all crops where soil compaction is a problem. The design provides deep tillage, loosening soil deeper than a tiller or plough is capable of reaching. Agricultural subsoilers, according to the Unverferth Company, can disrupt hardpan ground down to 24" depths.[1]

Various manufacturer's brochures claim that crops perform well during hot and dry seasons because roots penetrate soil layers deeper to reach moisture and nutrients. Brochures further claim that in wet conditions, the water passes easier through the shattered areas, reducing the possibility of crops drowning.

Agricultural tractors will have multiple deeper reaching blades; each blade is called a scarifier or shank. Purdue University's Dept. of Agriculture indicates that common subsoilers for agricultural use are available with 3, 5 or 7 shanks. These units can be up to 15' wide, some models are towed behind tractors, others are tractor mounted to the 3pt hitch.[2]

A form of this implement (with a single blade), a pipe-and-cable-laying plough, is used to lay buried cables or pipes, without the need to dig a deep trench and re-fill it.

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A stone picker (or rock picker) is an implement to remove the top layer of soil to separate and collect rocks and soil debris from good topsoil. It is usually tractor-pulled. A stone picker is similar in function to a rock windrower (rock rake); a stone picker generally digs to greater depths to remove stones and rocks.

Stone pickers are used in farming and landscaping, where stones need to be removed from the soil and ground surface to prevent damage to other farm machinery (such as hay balers, combines, and mowers), improve the soil for crop production, or improve the appearance of the ground surface in preparation for a lawn or a golf course. Surface stones and large rocks often left from plowing can damage a hay bailer, the header or reciprocating knives on a combine, and blades on a rotary mower. Land with rock instead of fine soil are often less useful for crops.

A stone picker has digging teeth, a conveyor system, a sieve or screen, and a stone bin. The digging teeth are at the leading edge of the stone picker and removes soil, which is placed on the conveyor system. If the sieve is not combined with the conveyor system, the conveyor system transports the stones and large rocks to a bin or hopper for periodic dumping. Some stone pickers use a large tractor, generally over 100 horsepower, equipped with hydraulics and power take-off driven mechanisms. PTO pump driven equipment can use 60 horsepower tractors. The tractor's hydraulics control the depth to which the stone picker digs to excavate soil material; whereas, the PTO controls the movement of the conveyor and picking system.

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A destoner is a machine that removes stones and clods from soil ridges and moves them to between the drills so that the drills are free from stones. It also helps when harvesting in wet conditions as the harvester can drive on a row of stones which helps improve traction.

It removes the stones by a series of webs (between two and five webs). The stones stay on the web and the clay falls through it. The stones travel thrugh the machine and the bigger stones fall into a boulder box and the smaller stones fall onto a cross converer and in turn fall into a trench . On the next pass the tractor tramps these stones down.

Destoner are usually fitted with steerable wheels which makes them more manageable at headlands. Some are fitted with hydraulic levelling.

Roller (agricultural tool) From Wikipedia, the free encyclopedia

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This article is about non-powered (agricultural) rollers. For self-propelled rollers, see road roller.

A 12 foot smooth roller

The roller is an agricultural tool used for flattening land or breaking up large clumps of soil, especially after ploughing. Typically, rollers are pulled by tractors or, prior to mechanisation, a team of animals such as horses or oxen.

Flatter land makes subsequent weed control and harvesting easier, and rolling can help to reduce moisture loss from cultivated soil. On grassland, rolling levels the land for mowing and compacts the soil surface.

For many uses a heavy roller is used, and rollers may be weighed in different ways. Heavy rollers may consist of one or more cylinders made of thick steel, a thinner steel cylinder filled with concrete, or a cylinder filled with water. A water-filled roller has the advantage that the water may be drained out for lighter use or for transport. In frost-prone areas a water filled roller

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must be drained for winter storage to avoid breakage due to the expansion for water as it turns to ice.

[edit] Segmented rollers

Cambridge roller-cultipacker

A field after rolling with a Cambridge (or similar) roller

On tilled soil a one-piece roller has the disadvantage that when turning corners the outer end of the roller has to rotate much faster than the inner end, forcing one or both ends to skid. A one-piece roller turned on soft ground will skid up a heap of soil at the outer radius, leaving heaps, which is counter-productive. Rollers are often made in two or three sections to reduce this problem, and the Cambridge roller overcomes it altogether by mounting many small segments onto one axle so that they can each rotate at local ground-speed.

The surface of rollers may be smooth, or it may be textured to help break up soil or to groove the final surface to reduce scouring from rain. Each segment of a Cambridge roller has a rib around its edge for this purpose.

Rollers may be ganged, or combined with other equipment such as mowers.

A broadcast seeder, alternately called a broadcast spreader, is a farm implement commonly used for spreading seed, lime, fertilizer, sand, ice melt, etc., and is an alternative to drop spreaders/seeders.[1]

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[edit] Types

ATV tow spreaders normally have a larger capacity to enable the coverage of larger areas

Broadcast seeders/spreaders vary considerably in size. The smallest are handheld with a hopper of several liters and which operate via hand cranking. A bit larger are push units with the spinning disk powered by gearing to the wheels. The next size up is designed to be towed behind a garden tractor or ATV. Very similar in size to the tow behind units are broadcast seeders that mount to the three-point hitch of a compact utility tractor, these are ideal for landscape and small property maintenance. Still larger are commercial broadcast seeders/spreaders designed and sized appropriately for agricultural tractors and mount to the tractor's 3pt hitch. The broadcast seeders that are mounted to a 3pt hitch are powered by a power take-off (P.T.O.) shaft from the tractor. At the largest size are pull behind or chassis mounted units for agricultural use that can spread widths of up to 90 feet.[2][3]

[edit] How they work

View of a tractor-operated broadcast seeder moved by three-point hitch and driven by PTO shaft

The basic operating concept of broadcast spreads is simple. A large material hopper is positioned over a horizontal spinning disk, the disk has a series of 3 or 4 fins attached to it which throw the dropped materials from the hopper out and away from the seeder/spreader.[4] Alternately a pendulum spreading mechanism may be employed, this method is more common in mid-sized commercial spreaders for improved consistency in spreading.[citation needed] The photos clearly show the material hopper. Hoppers are commonly made of plastic, painted steel, or stainless steel. Stainless steel is usually used in large commercial units for strength and because granular fertilizer is often quite corrosive.

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Some seeders/spreaders have directional fins to control the direction of the material that is thrown from the spreader. All broadcast spreaders require some form of power to spin the disk. On hand carried units, a hand crank spins gears to turn the disk. On tow behind units, the wheels spin a shaft that turns gears which, in turn, spin the disk. As is partially visible in one of the photos, with tractor mounted units, a mechanical P.T.O. shaft connected to the tractor and controlled by the tractor operator, spins the disk. There are some seeder/spreaders made for garden size tractors that use a 12 volt motor to spin the dispersing disk.

Planter (farm implement) From Wikipedia, the free encyclopedia

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A two row planter featuring John Deere "71 Flexi" row units

The John Deere DB120 48 row planter

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John Deere MaxEmerge XP Planter with Case IH AFS precision farming system which auto-steers using GPS

Like a grain drill a planter is an agricultural farm implement towed behind a tractor, used for sowing crops through a field.[1][2] It is connected to the tractor with a draw-bar, or a three-point hitch. Planters lay the seed down in precise manner along rows. Seeds are distributed through devices called row units.[1] The row units are spaced evenly along the planter.[1] Planters vary greatly in size, from 2 rows to 48, with the biggest in the world being the 48-row John Deere DB120. The space between the row units also vary greatly. The most common row spacing in the United States today is 30 inches.[1]

On smaller and older planters, a marker extends out to the side half the width of the planter and creates a line in the field where the tractor should be centered for the next pass. The marker is usually a single disc harrow disc on a rod on each side of the planter. On larger and more modern planters, GPS navigation and auto-steer systems for the tractor are often used, eliminating the need for the marker. Some precision farming equipment such as Case IH AFS uses GPS/RKS and computer controlled planter to sow seeds to precise position accurate within 2 cm. In irregular shaped field, the precision farming equipment will automatically hold the seed release over area already sewn when the tractor has to run overlapping pattern to avoid obstacles such as trees.

Older planters commonly have a seed bin for each row and a fertilizer bin for two or more rows. In each seed bin plates are installed with a certain number of teeth and tooth spacing according to the type of seed to be sown and the rate at which the seeds are to be sown. The tooth size (actually the size of the space between the teeth) is just big enough to allow one seed in at a time but not big enough for two. Modern planters often have a large bin for seeds that are distributed to each row.

A potato planter is a farm implement for sowing seed potatoes.

A manual planter is sometimes called a bell planter, which may have two farm hands sitting on the back whilst taking potatoes from a hopper. The length between potatoes is tolled by a bell, at the sound of which potatoes are thrown down tubes.

An automatic planter is hitched behind a farm tractor with a three-point linkage and towed. Cups lift seed potatoes from a hopper and drop them in tubes, planting up to eight drills at a time

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A seed drill is a sowing device that precisely positions seeds in the soil and then covers them. Before the introduction of the seed drill, the common practice was to plant seeds by hand. Besides being wasteful, planting was very imprecise and led to a poor distribution of seeds, leading to low productivity. The use of a seed drill can improve the ratio of crop yield by as much as nine times.

Contents [hide]

1 Description o 1.1 Uses

2 History 3 See also 4 Notes 5 Bibliography 6 External links

[edit] DescriptionIn older methods of planting, a field is initially prepared with a plough to a series of linear cuts known as furrows. The field is then seeded by throwing the seeds over the field, a method known as manual broadcasting. Seeds that landed in the furrows had better protection from the elements, and natural erosion or manual raking would preferentially cover them while leaving some exposed. The result was a field planted roughly in rows, but having a large number of plants outside the furrow lanes.

There are several downsides to this approach. The most obvious is that seeds that land outside the furrows will not have the growth shown by the plants sown in the furrow, since they are too shallow on the soil. Because of this, they are lost to the elements. Since the furrows represent only a portion of the field's area, and broadcasting distributes seeds fairly evenly, this results in considerable wastage of seeds. Less obvious are the effects of overseeding; all crops grow best at a certain density, which varies depending on the soil and weather conditions. Additional seeding above this limit will actually reduce crop yields, in spite of more plants being sown, as there will be competition among the plants for the minerals, water and the soil available. Another reason is that the mineral resources of the soil will also deplete at a much faster rate, thereby directly affecting the growth of the plants.

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[edit] Uses

1902 model 12-run seed drill produced by Monitor Manufacturing Company, Minneapolis, Minnesota.

Drilling is the term used for the mechanized sowing of an agricultural crop. Traditionally, a seed drill consists of a hopper of seeds arranged above a series of tubes that can be set at selected distances from each other to allow optimum growth of the resulting plants. Seed is metered using fluted paddles which rotate using a geared drive from one of the drill's land wheels - seed rate is altered by changing gear ratios. Most modern drills use air to convey seed in plastic tubes from the seed hopper to the coulters - it is an arrangement which allows seed drills to be much wider than the seed hopper - as much as 12m wide in some cases. The seed is metered mechanically into an airstream created by a hydraulically powered on-board fan and conveyed initially to a distribution head which sub-devides the seed into the pipes taking the seed to the individual coulters.

The seed drill allows farmers to sow seeds in well-spaced rows at specific depths at a specific seed rate; each tube creates a hole of a specific depth, drops in one or more seeds, and covers it over. This invention gave farmers much greater control over the depth that the seed was planted and the ability to cover the seeds without back-tracking. This greater control meant that seeds germinated consistently and in good soil. The result was an increased rate of germination, and a much-improved crop yield (up to eight times [1]).

A further important consideration was weed control. Broadcast seeding results in a random array of growing crops, making it difficult to control weeds using any method other than hand weeding. A field planted using a seed drill is much more uniform, typically in rows, allowing weeding with the hoe during the course of the growing season. Weeding by hand is laborious and poor weeding limits yield.

[edit] History

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Chinese double-tube seed drill, published by Song Yingxing in the Tiangong Kaiwu encyclopedia of 1637.

While the Sumerians used primitive single-tube seed drills around 1500 BC, the invention never reached Europe. Multi-tube iron seed drills were invented by the Chinese in the 2nd century BC.[2] This multi-tube seed drill has been credited with giving China an efficient food production system that allowed it to support its large population for millennia.[2] It has been conjectured that the seed drill was introduced in Europe following contacts with China.[2]

The first known European seed drill was attributed to Camillo Torello and patented by the Venetian Senate in 1566. A seed drill was described in detail by Tadeo Cavalina of Bologna in 1602.[2] In England, the seed drill was further refined by Jethro Tull in 1701 in the Agricultural Revolution. However, seed drills of this and successive types were both expensive and unreliable, as well as fragile. Seed drills would not come into widespread use in Europe until the mid-19th century.

Over the years seed drills have become more advanced and sophisticated but the technology has remained substantially the same. The first seed drills were small enough to be drawn by a single horse but the availability of steam and, later, gasoline tractors saw the development of larger and more efficient drills that allowed farmers to seed even larger tracts in a single day. Recent improvements to drills allow seed-drilling without prior tilling. This means that soils subject to erosion or moisture loss are protected until the seed germinates and grows enough to keep the soil in place. This also helps prevent soil loss by avoiding erosion after tilling.

A broadcast seeder, alternately called a broadcast spreader, is a farm implement commonly used for spreading seed, lime, fertilizer, sand, ice melt, etc., and is an alternative to drop spreaders/seeders.[1]

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[edit] Types

ATV tow spreaders normally have a larger capacity to enable the coverage of larger areas

Broadcast seeders/spreaders vary considerably in size. The smallest are handheld with a hopper of several liters and which operate via hand cranking. A bit larger are push units with the spinning disk powered by gearing to the wheels. The next size up is designed to be towed behind a garden tractor or ATV. Very similar in size to the tow behind units are broadcast seeders that mount to the three-point hitch of a compact utility tractor, these are ideal for landscape and small property maintenance. Still larger are commercial broadcast seeders/spreaders designed and sized appropriately for agricultural tractors and mount to the tractor's 3pt hitch. The broadcast seeders that are mounted to a 3pt hitch are powered by a power take-off (P.T.O.) shaft from the tractor. At the largest size are pull behind or chassis mounted units for agricultural use that can spread widths of up to 90 feet.[2][3]

[edit] How they work

View of a tractor-operated broadcast seeder moved by three-point hitch and driven by PTO shaft

The basic operating concept of broadcast spreads is simple. A large material hopper is positioned over a horizontal spinning disk, the disk has a series of 3 or 4 fins attached to it which throw the dropped materials from the hopper out and away from the seeder/spreader.[4] Alternately a pendulum spreading mechanism may be employed, this method is more common in mid-sized commercial spreaders for improved consistency in spreading.[citation needed] The photos clearly show the material hopper. Hoppers are commonly made of plastic, painted steel, or stainless steel. Stainless steel is usually used in large commercial units for strength and because granular fertilizer is often quite corrosive.

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Some seeders/spreaders have directional fins to control the direction of the material that is thrown from the spreader. All broadcast spreaders require some form of power to spin the disk. On hand carried units, a hand crank spins gears to turn the disk. On tow behind units, the wheels spin a shaft that turns gears which, in turn, spin the disk. As is partially visible in one of the photos, with tractor mounted units, a mechanical P.T.O. shaft connected to the tractor and controlled by the tractor operator, spins the disk. There are some seeder/spreaders made for garden size tractors that use a 12 volt motor to spin the dispersing disk.

A manure spreader or muck spreader or honey wagon is an agricultural machine used to distribute manure over a field as a fertilizer. A typical (modern) manure spreader consists of a trailer towed behind a tractor with a rotating mechanism driven by the tractor's power take off (PTO). Truck mounted manure spreaders are also common in North America.

Contents [hide] 

1 Operation 2 History 3 Notes 4 List of References 5 External links

[edit] OperationManure spreaders began as ground-driven units which could be pulled by a horse or team of horses. Many of these ground-driven spreaders are still produced today, mostly in the form of small units that can be pulled behind a larger garden tractor or an all terrain vehicle (ATV). In recent years hydraulic and PTO driven units have been developed to offer variable application rates. Several models are also designed with removable rotating mechanisms, attachable side extensions, and tailgates for hauling chopped forages, cereal grains, and other crops.

[edit] History

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An advertisement for a J.S.Kemp model spreader

The first successful automated manure spreader was designed by Joseph Kemp in 1875. At the time of his invention he was living in Waterloo, Canada but thereafter he moved to Newark Valley, NY and formed the J.S. Kemp Manufacturing Co. to manufacture and market his current and subsequent designs. In 1903 he expanded the company to Waterloo, Iowa before selling the design to International Harvester in 1906.[1][2][3]

The original New Idea spreader design. Note the paddle system at the rear that creates the 'widespreading' effect.

Joseph Oppenheim of Maria Stein, Ohio was the inventor of the first modern 'widespreading' manure spreader[4] and is honored as such in the Ohio Agricultural Hall of Fame.[5] Originally manure was thrown from a wagon.[6] Later, “manure unloaders” used a drag chain at the bottom of the wagon to pull the load of manure to the rear where it was shredded by a pair of beaters.[7] Because the unloaders deposited manure directly behind the wagon but with very little spreading to the sides, farmers still had to take the time-consuming step of heading into the fields with peg-tooth drags or similar implements to spread the manure in order to prevent burning the soil.[8]

Oppenheim, a schoolmaster in the small town, concerned that his older male students often missed school loading and spreading manure,[9] patented a wagon that, behind the drag chain and two beaters, incorporated a steel axle with several wooden paddles attached to the shaft at an angle to throw the manure outward in a broad pattern eliminating the necessity for manual spreading.[10] On October 18, 1899, Oppenheim began to produce his new manure spreader, incorporating the “widespread” paddle device.[11] Neighbors soon referred to it as “Oppenheim’s new idea” and Oppenheim adopted this name for his business.[12]

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Although Oppenheim died in November, 1901, the demand for the New Idea Spreader Company’s labor-saving “widespread” machines quickly grew and fifteen years later, under the direction of his oldest son, B.C. Oppenheim, and Henry Synck, one of Oppenheim’s first employees,[13] the company, had branches in eight states and an assembly plant in Guelph, Ontario. It had total sales in 1916 of $1,250,000.[14] Eight years later, in 1924, the factory was turning out 125 manure spreaders in an eight hour day.[15]and “became the brand that set the standards for spreader performance, durability and reliability decade after decade.”[16]

During the 1920s, Henry Synck,who became president of the company in 1936 when Joseph’s son, B.C. Oppenheim, died,[17] patented several improvements to the spreader.[18] In 1945 the Oppenheim family sold its controlling interest in the closely held New Idea Company to AVCO Manufacturing.[19] AVCO later sold the company to White Farm Equipment Company which in 1993 sold it to AGCO (Allis-Gleaner Corporation), the current owner.[20]

It is clear, however, that there were other competitors in this field, each of whom spread the manure by a slightly different technique. One of these is the Great Western Farm Equipment Line, produced in Chicago, IL.[21]

Sprayer From Wikipedia, the free encyclopedia

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This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2009)

Look up sprayer in Wiktionary, the free dictionary.

For other uses, see pesticide application, spray, spraying, and spray bottle.

Self-Propelled Row-crop Sprayer

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Case IH 3230 Patriot Sprayer

A sprayer is a device used to spray a liquid.

In agriculture, a sprayer is a piece of equipment that spray nozzles to apply herbicides, pesticides, and fertilizers to agricultural crops. Sprayers range in size from man-portable units (typically backpacks with spray guns) to self-propelled units similar to tractors, with boom mounts of 60–151 feet in length.

[edit] Types Backpack/knapsack Foot Garden Hand compression Power Stirrup

In Chile (South America) one of the best known brands is

1. REDIRECT Rautop

Drip irrigation From Wikipedia, the free encyclopedia

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This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (August 2011)

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A Emitter or dripper in action

Drip irrigation, also known as trickle irrigation or micro irrigation or localized irrigation, is an irrigation method which saves water and fertilizer by allowing water to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone, through a network of valves, pipes, tubing, and emitters.It is done with the help of narrow tubes which deliver water directly to the base of the plant.

Contents [hide]

1 History 2 Components and operation

o 2.1 Drip Irrigation for Garden 3 Advantage and disadvantages 4 Emitting Pipe 5 Emitter 6 References 7 Further reading

[edit] HistoryHeda irrigation has been used since ancient times when buried clay pots were filled with water, which would gradually seep into the grass. Modern drip irrigation began its development in Afghanistan in 1866 when researchers began experimenting with irrigation using clay pipe to create combination irrigation and drainage systems.[1] In 1913, E.B. House at Colorado State University succeeded in applying water to the root zone of plants without raising the water table. Perforated pipe was introduced in Germany[2] in the 1920s .

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Drip irrigation in New Mexico vineyard, 2002

Usage of plastic to hold and distribute water in drip irrigation was developed in Australia by Hannis Thill.[3] Refinement of this idea (involving a plastic emitter) was furthered in Israel by Simcha Blass and his son Yeshayahu. Instead of releasing water through tiny holes, blocked easily by tiny particles, water was released through larger and longer passageways by using velocity to slow water.

In the United States, in the early 1960s, the first drip tape, called Dew Hose, was developed by Richard Chapin of Chapin Watermatics (first system established during 1964).[4] Beginning in 1989, Jain irrigation helped pioneer effective water-management through drip irrigation in India.[5] Jain irrigation also introduced the `Integrated System Approach’, One-Stop-Shop for Farmers, `Infrastructure Status to Drip Irrigation & Farm as Industry.’ The latest developments in the field involve even further reduction in drip rates being delivered and less tendency to clog.

Modern drip irrigation has arguably become the world's most valued innovation in agriculture since the invention of the impact sprinkler in the 1930s, which offered the first practical alternative to surface irrigation. Drip irrigation may also use devices called micro-spray heads, which spray water in a small area, instead of dripping emitters. These are generally used on tree and vine crops with wider root zones. Subsurface drip irrigation (SDI) uses permanently or temporarily buried dripperline or drip tape located at or below the plant roots. It is becoming popular for row crop irrigation, especially in areas where water supplies are limited or recycled water is used for irrigation. Careful study of all the relevant factors like land topography, soil, water, crop and agro-climatic conditions are needed to determine the most suitable drip irrigation system and components to be used in a specific installation.

[edit] Components and operation

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Drip Irrigation System Layout and its parts

Components (listed in order from water source)

Pump or pressurized water source Water Filter(s) - Filtration Systems: Sand Separator like Hydro-Cyclone, Screen filters, Media

Filters, Disc Filters. Fertigation Systems (Venturi injector) and Chemigation Equipment (optional) Backwash Controller (Backflow Preventer) Pressure Control Valve (Pressure Regulator) Main Line (larger diameter Pipe and Pipe Fittings) Hand-operated, electronic, or hydraulic Control Valves and Safety Valves Smaller diameter polytube (often referred to as "laterals") Poly fittings and Accessories (to make connections) Emitting Devices at plants (ex. Emitter or Drippers, micro spray heads, inline drippers or inline

driptube) Note that in Drip irrigation systems Pump and valves may be manually or automatically

operated by a controller.

Most large drip irrigation systems employ some type of filter to prevent clogging of the small emitter flow path by small waterborne particles. New technologies are now being offered that minimize clogging. Some residential systems are installed without additional filters since potable water is already filtered at the water treatment plant. Virtually all drip irrigation equipment manufacturers recommend that filters be employed and generally will not honor warranties unless this is done. Last line filters just before the final delivery pipe are strongly recommended in addition to any other filtration system due to fine particle settlement and accidental insertion of particles in the intermediate lines.

Drip and subsurface drip irrigation is used almost exclusively when using recycled municipal waste water. Regulations typically do not permit spraying water through the air that has not been fully treated to potable water standards.

Because of the way the water is applied in a drip system, traditional surface applications of timed-release fertilizer are sometimes ineffective, so drip systems often mix liquid fertilizer with the irrigation water. This is called fertigation; fertigation and chemigation (application of pesticides and other chemicals to periodically clean out the system, such as chlorine or sulfuric acid) use chemical injectors such as diaphragm pumps, piston pumps, or venturi pumps. The chemicals may be added constantly whenever the system is irrigating or at intervals. Fertilizer

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savings of up to 95% are being reported from recent university field tests using drip fertigation and slow water delivery as compared to timed-release and irrigation by micro spray heads.

Properly designed, installed, and managed, drip irrigation may help achieve water conservation by reducing evaporation and deep drainage when compared to other types of irrigation such as flood or overhead sprinklers since water can be more precisely applied to the plant roots. In addition, drip can eliminate many diseases that are spread through water contact with the foliage. Finally, in regions where water supplies are severely limited, there may be no actual water savings, but rather simply an increase in production while using the same amount of water as before. In very arid regions or on sandy soils, the preferred method is to apply the irrigation water as slowly as possible.

Pulsed irrigation is sometimes used to decrease the amount of water delivered to the plant at any one time, thus reducing runoff or deep percolation. Pulsed systems are typically expensive and require extensive maintenance. Therefore, the latest efforts by emitter manufacturers are focused toward developing new technologies that deliver irrigation water at ultra-low flow rates, i.e. less than 1.0 liter per hour. Slow and even delivery further improves water use efficiency without incurring the expense and complexity of pulsed delivery equipment.

Drip irrigation is used by farms, commercial greenhouses, and residential gardeners.Drip irrigation is adopted extensively in areas of acute water scarcity and especially for crops such as coconuts, containerized landscape trees, grapes, bananas, ber, brinjal, citrus, strawberries, sugarcane, cotton, maize, and tomatoes.

[edit] Drip Irrigation for Garden

Drip irrigation for garden available in drip kits are increasingly popular for the homeowner and consist of a timer, hose and emitter. Hoses that are 4 mm in diameter are used to irrigate flower pots.

[edit] Advantage and disadvantages

Banana plants with drip irrigation in Maharashtra, India

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The advantages of drip irrigation are:

Minimized fertilizer/nutrient loss due to localized application and reduced leaching. High water application efficiency. Levelling of the field not necessary. Ability to irrigate irregular shaped fields. Allows safe use of recycled water. Moisture within the root zone can be maintained at field capacity. Soil type plays less important role in frequency of irrigation. Minimized soil erosion. Minimized weed growth Highly uniform distribution of water i.e., controlled by output of each nozzle. Lower labour cost. Variation in supply can be regulated by regulating the valves and drippers. Fertigation can easily be included with minimal waste of fertilizers. Foliage remains dry thus reducing the risk of disease. Usually operated at lower pressure than other types of pressurised irrigation, reducing energy

costs.

The disadvantages of drip irrigation are:

Expense. Initial cost can be more than overhead systems. Waste. The sun can affect the tubes used for drip irrigation, shortening their usable life.

Longevity is variable. Clogging. If the water is not properly filtered and the equipment not properly maintained, it can

result in clogging. Drip irrigation might be unsatisfactory if herbicides or top dressed fertilizers need sprinkler

irrigation for activation. Drip tape causes extra cleanup costs after harvest. You'll need to plan for drip tape winding,

disposal, recycling or reuse. Waste of water, time & harvest, if not installed properly. These systems require careful study of

all the relevant factors like land topography, soil, water, crop and agro-climatic conditions, and suitability of drip irrigation system and its components.

Germination Problems. In lighter soils subsurface drip may be unable to wet the soil surface for germination. Requires careful consideration of the installation depth.

Salinity. Most drip systems are designed for high efficiency, meaning little or no leaching fraction. Without sufficient leaching, salts applied with the irrigation water may build up in the root zone, usually at the edge of the wetting pattern. On the other hand, drip irrigation avoids the high capillary potential of traditional surface-applied irrigation, which can draw salt deposits up from deposits below.

[edit] Emitting PipeAn Emitting Pipe is a type of drip irrigation tubing with emitters pre-installed at the factory with specific distance & flow per hour as per crop distance.

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[edit] Emitter

Horticulture drip emitter in a Pot

An emitter is also called a dripper and is used to transfer water from a pipe or tube to the area that is to be irrigated. Typical emitter flow rates are from 0.16 to 4.0 US gallons per hour (0.6 to 16 L/h). In many emitters, flow will vary with pressure, while some emitters are pressure compensating.

These emitters employ silicone diaphragms or other means to allow them to maintain a near-constant flow over a range of pressures, for example from 10 to 50 psi (70 to 350 kPa).[citation needed]

Hydroponics From Wikipedia, the free encyclopedia

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For the EP by 311, see Hydroponic (EP).

This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations. (March 2011)

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NASA researcher checking hydroponic onions with Bibb lettuce to his left and radishes to the right

Hydroponics is a subset of hydroculture and is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, expanded clay or coconut husk.

Researchers discovered in the 18th century that plants absorb essential mineral nutrients as inorganic ions in water.[citation needed] In natural conditions, soil acts as a mineral nutrient reservoir but the soil itself is not essential to plant growth. When the mineral nutrients in the soil dissolve in water, plant roots are able to absorb them. When the required mineral nutrients are introduced into a plant's water supply artificially, soil is no longer required for the plant to thrive. Almost any terrestrial plant will grow with hydroponics. Hydroponics is also a standard technique in biology research and teaching.

Contents [hide]

1 History 2 Origin

o 2.1 Soilless culture 3 Advantages 4 Disadvantages 5 Techniques

o 5.1 Static solution culture o 5.2 Continuous-flow solution culture o 5.3 Aeroponics o 5.4 Passive sub-irrigation o 5.5 Ebb and flow or flood and drain sub-irrigation o 5.6 Run to waste o 5.7 Deep water culture o 5.8 Bubbleponics

6 Medium o 6.1 Expanded clay aggregate o 6.2 Rock wool o 6.3 Coir o 6.4 Perlite o 6.5 Pumice o 6.6 Vermiculite o 6.7 Sand o 6.8 Gravel o 6.9 Brick shards o 6.10 Polystyrene packing peanuts

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o 6.11 Wood fibre 7 Nutrient solutions 8 Commercial 9 Advancements 10 Charity Use 11 See also 12 References 13 External links

[edit] HistoryThe very earliest published work on growing terrestrial plants without soil was the 1627 book, Sylva Sylvarum by Francis Bacon, printed a year after his death. Water culture became a popular research technique after that. In 1699, John Woodward published his water culture experiments with spearmint. He found that plants in less-pure water sources grew better than plants in distilled water. By 1842, a list of nine elements believed to be essential to plant growth had been compiled, and the discoveries of the German botanists Julius von Sachs and Wilhelm Knop, in the years 1859-65, resulted in a development of the technique of soilless cultivation.[1] Growth of terrestrial plants without soil in mineral nutrient solutions was called solution culture. It quickly became a standard research and teaching technique and is still widely used today. Solution culture is now considered a type of hydroponics where there is no inert medium.

In 1929, William Frederick Gericke of the University of California at Berkeley began publicly promoting that solution culture be used for agricultural crop production.[2] He first termed it aquaculture but later found that aquaculture was already applied to culture of aquatic organisms. Gericke created a sensation by growing tomato vines twenty-five feet high in his back yard in mineral nutrient solutions rather than soil.[3] By analogy with the ancient Greek term for agriculture, geoponics, the science of cultivating the earth, Gericke coined the term hydroponics in 1937 (although he asserts that the term was suggested by W. A. Setchell, of the University of California) for the culture of plants in water (from the Greek hydro-, "water", and ponos, "labour").[1]

Reports of Gericke's work and his claims that hydroponics would revolutionize plant agriculture prompted a huge number of requests for further information. Gericke refused to reveal his secrets claiming he had done the work at home on his own time. This refusal eventually resulted in his leaving the University of California. In 1940, he wrote the book, Complete Guide to Soilless Gardening.

Two other plant nutritionists at the University of California were asked to research Gericke's claims. Dennis R. Hoagland [4] and Daniel I. Arnon [5] wrote a classic 1938 agricultural bulletin, The Water Culture Method for Growing Plants Without Soil,[6] debunking the exaggerated claims made about hydroponics. Hoagland and Arnon found that hydroponic crop yields were no better than crop yields with good-quality soils. Crop yields were ultimately limited by factors other than mineral nutrients, especially light. This research, however, overlooked the fact that hydroponics has other advantages including the fact that the roots of the plant have constant

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access to oxygen and that the plants have access to as much or as little water as they need. This is important as one of the most common errors when growing is over- and under- watering; and hydroponics prevents this from occurring as large amounts of water can be made available to the plant and any water not used, drained away, recirculated, or actively aerated, eliminating anoxic conditions, which drown root systems in soil. In soil, a grower needs to be very experienced to know exactly how much water to feed the plant. Too much and the plant will not be able to access oxygen; too little and the plant will lose the ability to transport nutrients, which are typically moved into the roots while in solution. These two researchers developed several formulas for mineral nutrient solutions, known as Hoagland solution. Modified Hoagland solutions are still used today.

One of the early successes of hydroponics occurred on Wake Island, a rocky atoll in the Pacific Ocean used as a refuelling stop for Pan American Airlines. Hydroponics was used there in the 1930s to grow vegetables for the passengers. Hydroponics was a necessity on Wake Island because there was no soil, and it was prohibitively expensive to airlift in fresh vegetables.

In the 1960s, Allen Cooper of England developed the Nutrient film technique. The Land Pavilion at Walt Disney World's EPCOT Center opened in 1982 and prominently features a variety of hydroponic techniques. In recent decades, NASA has done extensive hydroponic research for their Controlled Ecological Life Support System or CELSS. Hydroponics intended to take place on Mars are using LED lighting to grow in different color spectrum with much less heat.

[edit] Origin[edit] Soilless culture

Gericke originally defined hydroponics as crop growth in mineral nutrient solutions. Hydroponics is a subset of soilless culture. Many types of soilless culture do not use the mineral nutrient solutions required for hydroponics.

Billions of container plants are produced annually, including fruit, shade, and ornamental trees, shrubs, forest seedlings, vegetable seedlings, bedding plants, herbaceous perennials, and vines. Most container plants are produced in soilless media, representing soil less culture. However, most are not hydroponics because the soilless medium often provides some of the mineral nutrients via slow release fertilizers, cation exchange, and decomposition of the organic medium itself. Most soil less media for container plants also contain organic materials such as peat or composted bark, which provide some nitrogen to the plant. Greenhouse growth of plants in peat bags is often termed hydroponics, but, in the technical sense, it is not because the medium provides some of the mineral nutrients.

Plants that are not traditionally grown in a climate would be possible to grow using a controlled environment system like hydroponics. During World War II, produce was grown with hydroponics on the barren Pacific Islands. According to a 1938 Times magazine article, this was one of the first times that commercial use of hydroponics was used on such a large scale to feed people. This group of islands was used as a refuelling stop for Pan-Am Airways, and the food was used to feed the staff and crew. This means that salad greens could be grown in Antarctica

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or even the Mojave Desert. NASA has also looked to utilize hydroponics in the space program. Ray Wheeler, plant physiologist at Kennedy Space Center’s Space Life Science Lab, believes that hydroponics will create advances within space travel. He terms this as “a life support system with the biological component of growing plants — called a bioregenerative life support system. It has several benefits for NASA.”[7] These scientists are researching how different amounts of light, temperature and carbon dioxide, along with plant species can be grown and cultivated on planets like Mars.

[edit] AdvantagesSome of the reasons why hydroponics is being adapted around the world for food production are the following:

No soil is needed The water stays in the system and can be reused - thus, lower water costs It is possible to control the nutrition levels in their entirety - thus, lower nutrition costs No nutrition pollution is released into the environment because of the controlled system Stable and high yields Pests and diseases are easier to get rid of than in soil because of the container's mobility It is easier to harvest No pesticide damage

Today, hydroponics is an established branch of agronomy. Progress has been rapid, and results obtained in various countries have proved it to be thoroughly practical and to have very definite advantages over conventional methods of horticulture.

There are two chief merits of the soil-less cultivation of plants. First, hydroponics may potentially produce much higher crop yields. Also, hydroponics can be used in places where in-ground agriculture or gardening are not possible.

[edit] DisadvantagesWithout soil as a buffer, any failure to the hydroponic system leads to rapid plant death. Other disadvantages include pathogen attacks such as damp-off due to Verticillium wilt caused by the high moisture levels associated with hydroponics and over watering of soil based plants. Also, many hydroponic plants require different fertilizers and containment systems.[8] To produce the mineral wool and the fertilizers that are needed to use this method, a large amount of energy is required.

[edit] TechniquesThe two main types of hydroponics are solution culture and medium culture. Solution culture does not use a solid medium for the roots, just the nutrient solution. The three main types of solution cultures are static solution culture, continuous-flow solution culture and aeroponics. The

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medium culture method has a solid medium for the roots and is named for the type of medium, e.g., sand culture, gravel culture, or rockwool culture.

There are two main variations for each medium, sub-irrigation and top irrigation[specify]. For all techniques, most hydroponic reservoirs are now built of plastic, but other materials have been used including concrete, glass, metal, vegetable solids, and wood. The containers should exclude light to prevent algae growth in the nutrient solution.

[edit] Static solution culture

In static solution culture, plants are grown in containers of nutrient solution, such as glass Mason jars (typically, in-home applications), plastic buckets, tubs, or tanks. The solution is usually gently aerated but may be un-aerated. If un-aerated, the solution level is kept low enough that enough roots are above the solution so they get adequate oxygen. A hole is cut in the lid of the reservoir for each plant. There can be one to many plants per reservoir. Reservoir size can be increased as plant size increases. A home made system can be constructed from plastic food containers or glass canning jars with aeration provided by an aquarium pump, aquarium airline tubing and aquarium valves. Clear containers are covered with aluminium foil, butcher paper, black plastic, or other material to exclude light, thus helping to eliminate the formation of algae. The nutrient solution is changed either on a schedule, such as once per week, or when the concentration drops below a certain level as determined with an electrical conductivity meter. Whenever the solution is depleted below a certain level, either water or fresh nutrient solution is added, A Mariotte's bottle, or a float valve, can be used to automatically maintain the solution level. In raft solution culture, plants are placed in a sheet of buoyant plastic that is floated on the surface of the nutrient solution. That way, the solution level never drops below the roots.

[edit] Continuous-flow solution culture

In continuous-flow solution culture, the nutrient solution constantly flows past the roots. It is much easier to automate than the static solution culture because sampling and adjustments to the temperature and nutrient concentrations can be made in a large storage tank that has potential to serve thousands of plants. A popular variation is the nutrient film technique or NFT, whereby a very shallow stream of water containing all the dissolved nutrients required for plant growth is recirculated past the bare roots of plants in a watertight thick root mat, which develops in the bottom of the channel, has an upper surface that, although moist, is in the air. Subsequent to this, an abundant supply of oxygen is provided to the roots of the plants. A properly designed NFT system is based on using the right channel slope, the right flow rate, and the right channel length. The main advantage of the NFT system over other forms of hydroponics is that the plant roots are exposed to adequate supplies of water, oxygen, and nutrients. In all other forms of production, there is a conflict between the supply of these requirements, since excessive or deficient amounts of one results in an imbalance of one or both of the others. NFT, because of its design, provides a system where all three requirements for healthy plant growth can be met at the same time, provided that the simple concept of NFT is always remembered and practised. The result of these advantages is that higher yields of high-quality produce are obtained over an extended period of cropping. A downside of NFT is that it has very little buffering against

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interruptions in the flow, e.g., power outages. But, overall, it is probably one of the more productive techniques.

The same design characteristics apply to all conventional NFT systems. While slopes along channels of 1:100 have been recommended, in practice it is difficult to build a base for channels that is sufficiently true to enable nutrient films to flow without ponding in locally depressed areas. As a consequence, it is recommended that slopes of 1:30 to 1:40 are used. This allows for minor irregularities in the surface, but, even with these slopes, ponding and water logging may occur. The slope may be provided by the floor, or benches or racks may hold the channels and provide the required slope. Both methods are used and depend on local requirements, often determined by the site and crop requirements.

As a general guide, flow rates for each gully should be 1 liter per minute. At planting, rates may be half this and the upper limit of 2 L/min appears about the maximum. Flow rates beyond these extremes are often associated with nutritional problems. Depressed growth rates of many crops have been observed when channels exceed 12 metres in length. On rapidly growing crops, tests have indicated that, while oxygen levels remain adequate, nitrogen may be depleted over the length of the gully. As a consequence, channel length should not exceed 10–15 metres. In situations where this is not possible, the reductions in growth can be eliminated by placing another nutrient feed halfway along the gully and reducing flow rates to 1 L/min through each outlet.

[edit] AeroponicsMain article: Aeroponics

Aeroponics is a system wherein roots are continuously or discontinuously kept in an environment saturated with fine drops (a mist or aerosol) of nutrient solution. The method requires no substrate and entails growing plants with their roots suspended in a deep air or growth chamber with the roots periodically wetted with a fine mist of atomized nutrients. Excellent aeration is the main advantage of aeroponics.

Aeroponic techniques have proved to be commercially successful for propagation, seed germination, seed potato production, tomato production, leaf crops, and micro-greens.[9] Since inventor Richard Stoner commercialized aeroponic technology in 1983, aeroponics has been implemented as an alternative to water intensive hydroponic systems worldwide.[10] The limitation of hydroponics is the fact that 1 kg of water can only hold 8 mg of air, no matter whether aerators are utilized or not.

Another distinct advantage of aeroponics over hydroponics is that any species of plants can be grown in a true aeroponic system because the micro environment of an aeroponic can be finely controlled. The limitation of hydroponics is that only certain species of plants can survive for so long in water before they become water logged. The advantage of aeroponics is that suspended aeroponic plants receive 100% of the available oxygen and carbon dioxide to the roots zone, stems, and leaves,[11] thus accelerating biomass growth and reducing rooting times. NASA research has shown that aeroponically grown plants have an 80% increase in dry weight biomass (essential minerals) compared to hydroponically grown plants. Aeroponics used 65% less water

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than hydroponics. NASA also concluded that aeroponically grown plants requires ¼ the nutrient input compared to hydroponics. Unlike hydroponically grown plants, aeroponically grown plants will not suffer transplant shock when transplanted to soil, and offers growers the ability to reduce the spread of disease and pathogens.[12] Aeroponics is also widely used in laboratory studies of plant physiology and plant pathology. Aeroponic techniques have been given special attention from NASA since a mist is easier to handle than a liquid in a zero gravity environment.

[edit] Passive sub-irrigationMain article: Passive hydroponics

Passive sub-irrigation, also known as passive hydroponics or semi-hydroponics, is a method wherein plants are grown in an inert porous medium that transports water and fertilizer to the roots by capillary action from a separate reservoir as necessary, reducing labour and providing a constant supply of water to the roots. In the simplest method, the pot sits in a shallow solution of fertilizer and water or on a capillary mat saturated with nutrient solution. The various hydroponic media available, such as expanded clay and coconut husk, contain more air space than more traditional potting mixes, delivering increased oxygen to the roots, which is important in epiphytic plants such as orchids and bromeliads, whose roots are exposed to the air in nature. Additional advantages of passive hydroponics are the reduction of root rot and the additional ambient humidity provided through evaporations.

[edit] Ebb and flow or flood and drain sub-irrigationMain article: Ebb and flow

In its simplest form, there is a tray above a reservoir of nutrient solution. Either the tray is filled with growing medium (clay granules being the most common) and planted directly or pots of medium stand in the tray. At regular intervals, a simple timer causes a pump to fill the upper tray with nutrient solution, after which the solution drains back down into the reservoir. This keeps the medium regularly flushed with nutrients and air. Once the upper tray fills past the drain stop, it begins recirculating the water until the timer turns the pump off, and the water in the upper tray drains back into the reservoirs.

[edit] Run to waste

In a run to waste system, nutrient and water solution is periodically applied to the medium surface. This may be done in its simplest form, by manually applying a nutrient-and-water solution one or more times per day in a container of inert growing media, such as rockwool, perlite, vermiculite, coco fibre, or sand. In a slightly more complex system, it is automated with a delivery pump, a timer and irrigation tubing to deliver nutrient solution with a delivery frequency that is governed by the key parameters of plant size, plant growing stage, climate, substrate, and substrate conductivity, pH, and water content.

In a commercial setting, watering frequency is multi factorial and governed by computers or PLCs.

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Commercial hydroponics production of large plants like tomatoes, cucumber, and peppers use one form or another of run to waste hydroponics.

In environmentally responsible uses, the nutrient rich waste is collected and processed through an on site filtration system to be used many times, making the system very productive.[13]

[edit] Deep water cultureMain article: Deep water culture

The hydroponic method of plant production by means of suspending the plant roots in a solution of nutrient-rich, oxygenated water. Traditional methods favor the use of plastic buckets and large containers with the plant contained in a net pot suspended from the centre of the lid and the roots suspended in the nutrient solution. The solution is oxygen saturated from an air pump combined with porous stones. With this method, the plants grow much faster because of the high amount of oxygen that the roots receive.[14]

[edit] Bubbleponics

"Bubbleponics" is the art of delivering highly oxygenated nutrient solution direct to the root zone of plants. While Deep Water Culture involves the plant roots hanging down into a reservoir of water below, the term Bubbleponics describes a top-fed Deep Water Culture (DWC) hydroponic system. In this method, the water is pumped from the reservoir up to the roots (top feeding). The water is released over the plant's roots and then runs back into the reservoir below in a constantly recirculating system. As with Deep Water Culture, there is an airstone in the reservoir that pumps air into the water via a hose from outside the reservoir. The airstone helps add oxygen to the water. Both the airstone and the water pump run 24 hours a day.

The biggest advantages with Bubbleponics over Deep Water Culture involve increased growth during the first few weeks. With Deep Water Culture, there is a time where the roots have not reached the water yet. With Bubbleponics, the roots get easy access to water from the beginning and will grow to the reservoir below much more quickly than with a Deep Water Culture system. Once the roots have reached the reservoir below, there is not a huge advantage with Bubbleponics over Deep Water Culture. However, due to the quicker growth in the beginning, a few weeks of grow time can be shaved off.[15]

[edit] MediumOne of the most obvious decisions hydroponic farmers have to make is which medium they should use. Different media are appropriate for different growing techniques.

[edit] Expanded clay aggregateMain article: Expanded clay aggregate

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Expanded clay pebbles.

Baked clay pellets, are suitable for hydroponic systems in which all nutrients are carefully controlled in water solution. The clay pellets are inert, pH neutral and do not contain any nutrient value.

The clay is formed into round pellets and fired in rotary kilns at 1,200 °C (2,190 °F). This causes the clay to expand, like popcorn, and become porous. It is light in weight, and does not compact over time. The shape of an individual pellet can be irregular or uniform depending on brand and manufacturing process. The manufacturers consider expanded clay to be an ecologically sustainable and re-usable growing medium because of its ability to be cleaned and sterilized, typically by washing in solutions of white vinegar, chlorine bleach, or hydrogen peroxide (H2O2), and rinsing completely.

Another view is that clay pebbles are best not re-used even when they are cleaned, due to root growth that may enter the medium. Breaking open a clay pebble after a crop has been grown will reveal this growth.

[edit] Rock wool

Rock wool (mineral wool) is the most widely used medium in hydroponics. Rock wool is an inert substrate suitable for both run to waste and recirculating systems. Rock wool is made from molten rock, basalt or 'slag' that is spun into bundles of single filament fibres, and bonded into a medium capable of capillary action, and are in effect protected from most common microbiological degradation. Rockwool has many advantages and disadvantages. Advantages include its proven efficiency and effectiveness as a commercial hydroponic substrate. Disadvantages include its classification as a possible carcinogen.

[edit] Coir

Coco Peat, also known as coir or coco, is the leftover material after the fibres have been removed from the outermost shell (bolster) of the coconut. Coir is a 100% natural grow and flowering medium. Coconut Coir is colonized with trichoderma Fungi, which protects roots and stimulates root growth. It is extremely difficult to over water coir due to its perfect air-to-water ratio, plant

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roots thrive in this environment, coir has a high cation exchange, meaning it can store unused minerals to be released to the plant as and when it requires it. Coir is available in many forms, most common is coco peat, which has the appearance and texture of soil but contains no mineral content.

[edit] Perlite

Perlite is a volcanic rock that has been superheated into very lightweight expanded glass pebbles. It is used loose or in plastic sleeves immersed in the water. It is also used in potting soil mixes to decrease soil density. Perlite has similar properties and uses to vermiculite but, in general, holds more air and less water. If not contained, it can float if flood and drain feeding is used. It is a fusion of granite, obsidian, pumice and basalt. This volcanic rock is naturally fused at high temperatures undergoing what is called "Fusionic Metamorphosis".

[edit] Pumice

Like perlite, pumice is a lightweight, mined volcanic rock that finds application in hydroponics.

[edit] Vermiculite

Like perlite, vermiculite is a mineral that has been superheated until it has expanded into light pebbles. Vermiculite holds more water than perlite and has a natural "wicking" property that can draw water and nutrients in a passive hydroponic system. If too much water and not enough air surrounds the plants roots, it is possible to gradually lower the medium's water-retention capability by mixing in increasing quantities of perlite.

[edit] Sand

Sand is cheap and easily available. However, it is heavy, does not hold water very well, and it must be sterilized between use.

[edit] Gravel

The same type that is used in aquariums, though any small gravel can be used, provided it is washed first. Indeed, plants growing in a typical traditional gravel filter bed, with water circulated using electric powerhead pumps, are in effect being grown using gravel hydroponics. Gravel is inexpensive, easy to keep clean, drains well and will not become waterlogged. However, it is also heavy, and, if the system does not provide continuous water, the plant roots may dry out.

[edit] Brick shards

Brick shards have similar properties to gravel. They have the added disadvantages of possibly altering the pH and requiring extra cleaning before reuse.

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[edit] Polystyrene packing peanuts

Polystyrene packing peanuts are inexpensive, readily available, and have excellent drainage. However, they can be too lightweight for some uses. They are used mainly in closed-tube systems. Note that polystyrene peanuts must be used; biodegradable packing peanuts will decompose into a sludge. Plants may absorb styrene and pass it to their consumers; this is a possible health risk.

[edit] Wood fibre

Wood fibre, produced from steam friction of wood, is a very efficient organic substrate for hydroponics. It has the advantage that it keeps its structure for a very long time.

[edit] Nutrient solutionsPlant nutrients used in hydroponics are dissolved in the water and are mostly in inorganic and ionic form. Primary among the dissolved cations (positively charged ions) are Ca2+ (calcium), Mg2+ (magnesium), and K+ (potassium); the major nutrient anions in nutrient solutions are NO−3 (nitrate), SO2−4 (sulfate), and H2PO−4 (dihydrogen phosphate).

Numerous 'recipes' for hydroponic solutions are available. Many use different combinations of chemicals to reach similar total final compositions. Commonly used chemicals for the macronutrients include potassium nitrate, calcium nitrate, potassium phosphate, and magnesium sulfate. Various micronutrients are typically added to hydroponic solutions to supply essential elements; among them are Fe (iron), Mn (manganese), Cu (copper), Zn (zinc), B (boron), Cl (chlorine), and Ni (nickel). Chelating agents are sometimes used to keep Fe soluble. Many variations of the nutrient solutions used by Arnon and Hoagland (see above) have been styled 'modified Hoagland solutions' and are widely used. Variation of different mixes throughout the plant life-cycle, further optimizes its nutritional value.[16] Plants will change the composition of the nutrient solutions upon contact by depleting specific nutrients more rapidly than others, removing water from the solution, and altering the pH by excretion of either acidity or alkalinity.[17] Care is required not to allow salt concentrations to become too high, nutrients to become too depleted, or pH to wander far from the desired value.

Although pre-mixed concentrated nutrient solutions are generally purchased from commercial nutrient manufacturers by hydroponic hobbyists and small commercial growers, several tools exists to help anyone prepare their own solutions without extensive knowledge about chemistry. The free and open source tools HydroBuddy[18] and HydroCal[19] have been created by professional chemists to help any hydroponics grower prepare their own nutrient solutions. The first program is available for Windows, Mac and Linux while the second one can be used through a simple java interface. Both programs allow for basic nutrient solution preparation although HydroBuddy provides added functionality to use and save custom substances, save formulations and predict electrical conductivity values.

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The well-oxygenated and enlightened environment promotes the development of algae. It is therefore necessary to wrap the tank with black film obscuring all light.

Organic hydroponics uses the solution containing microorganisms. In organic hydroponics, organic fertilizer can be added in the hydroponic solution because microorganisms degrade organic fertilizer into inorganic nutrients. In contrast, conventional hydroponics cannot use organic fertilizer because organic compounds in the hydroponic solution show phytotoxic effects.

[edit] CommercialSome commercial installations use no pesticides or herbicides, preferring integrated pest management techniques. There is often a price premium willingly paid by consumers for produce that is labelled "organic". Some states in the USA require soil as an essential to obtain organic certification. There are also overlapping and somewhat contradictory rules established by the US Federal Government, so some food grown with hydroponics can be certified organic.

Hydroponics also saves water; it uses as little as 1⁄20 the amount as a regular farm to produce the same amount of food. The water table can be impacted by the water use and run-off of chemicals from farms, but hydroponics may minimize impact as well as having the advantage that water use and water returns are easier to measure. This can save the farmer money by allowing reduced water use and the ability to measure consequences to the land around a farm.

To increase plant growth, lighting systems such as metal halide lamps for growing stage only or high-pressure sodium for growing/flowering/blooming stage are used to lengthen the day or to supplement natural sunshine if it is scarce. Metal halide emits more light in the blue spectrum, making it ideal for plant growth but is harmful to unprotected skin and can cause skin cancer. High-pressure sodium emits more light in the red spectrum, meaning that it is best suited for supplementing natural sunshine and can be used throughout the growing cycle. However, these lighting systems require large amounts of electricity to operate, making efficiency and safety very critical.

The environment in a hydroponics greenhouse is tightly controlled for maximum efficiency, and this new mindset is called soil-less/controlled-environment agriculture (CEA). With this growers can make ultra-premium foods anywhere in the world, regardless of temperature and growing seasons. Growers monitor the temperature, humidity, and pH level constantly.

Hydroponics have been used to enhance vegetables to provide more nutritional value. A hydroponic farmer in Virginia has developed a calcium and potassium enriched head of lettuce, scheduled to be widely available in April 2007. Grocers in test markets have said that the lettuce sells "very well", and the farmers claim that their hydroponic lettuce uses 90% less water than traditional soil farming.[20]

[edit] Advancements

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With pest problems reduced, and nutrients constantly fed to the roots, productivity in hydroponics is high, although plant growth can be limited by the low levels of carbon dioxide in the atmosphere, or limited light exposure. To increase yield further, some sealed greenhouses inject carbon dioxide into their environment to help growth (CO2 enrichment), add lights to lengthen the day, or control vegetative growth, etc.

[edit] Charity UseA number of hydroponic experts are now promoting hydroponic solutions as cheap ways of producing food in areas with bad soil. As hydroponic system use less water to grow than traditional farming it is also a more efficient use of resources.[21]

[edit] See also Aeroponics Aquaponics Folkewall Grow box Growroom Organoponics Passive hydroponics Vertical farming Xeriscaping


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