agriculture engineering-chptr 11

CULTIVATION AND SEEDBED PREPARATION

Tillage and CultivationTillageis defined as those mechanical, soil stirring actions carried on for the purpose of nurturing crops

Objective:To provide a suitable environment for seed germination, root growth, weed growth, soil erosion control and moisture control

Tillage machinery: Tools or implements used to obtain the above

Cultivation

• is an operation that requires some kind of tool hat will stir the surface of the soil to a shallow depth in such a manner that young weeds will be destroyed and crop growth promoted

• usually begins soon after the emergence of young seedlings as weeds generally emerge about the same time as the crop

Tillage Classification

Secondary tillagePrimary tillage

Primary Tillage

more aggressive, deeper operation and usually leaves the surface roughcut and shatters soil

Implements: 1. Mouldboard and disc plough2. Chisel plough3. Sub soilers4. Rotary tillers or cultivators

Secondary Tillageworks the soil to shallow depthlevels and firm the soilcloses air pocketskill weeds and helps conserve moisture

Implements: 1. Disc, spring tooth and spike tooth harrow2. Spring and rigid tined cultivators2. Ridgers, bedders or listers4. Roller pockets and roller harrows5. Weed control implement

Tillage machines or implements can be further classified into:mounted, semi-mounted, trailed or drawn implements

Mounted implements• Attached to the tractor by 3 point hitch

linkages• Implements can be raised or lowered by the

hydraulic system • Example: A mounted 3 disc plough

Semi-mounted implements• Attached to the tractor 2 point or 3 point

linkage and these implements are normally provided with wheels to help in better performance of the machine

• Example: A seed drill – implement can be raised or lowered

Trailed implements• Attached to the tractor’s drawbar and this

cannot be raised or lowered• Implement trailed the tractor as it moves• Implements are heavy and usually provided

with wheels for easy hitching to the back of tractor and better stability

Example: Trailed moldboard plough

Disc Plow, Rotovator, Harrow and Ridges

PLOW

One of the oldest agriculture equipments and is generally considered to be the most importanttillage tool

It is used to cut, turn up and break up soil while turning over weeds

1. Moldboard PlowMostly used for primary tillage in seedbed preparation

a. One way plow - Design to turn the furrow slices only to the right

b. Two way plow Has 2 sets of opposed bottoms that can be used selectively

All furrows can be turned toward the same side of the field by using right hand bottoms for one direction of travel and the left hand bottom on the return

Used for plowing irrigated lands since it eliminated back furrows and dead furrows and leaves the field nearly level

2. Disc PlowDisk plow was brought out in an effort to reduce friction by making a rolling bottom instead of a bottom that would slide along the furrow

Consists of a series of individually mounted, inclined disc blades on a frame supported by wheelsUsed when moldboard plow does not work satisfactorily:a. hard dry soilsb. stony or stumpy fieldsc. soils containing heavy rootsd. loose, push type soils and abrasive soil

Built with heavy frame and wheels; in a hard dry soil, a disc plow can be forced into ground by its weight

Uses: i. Controlling weeds, cutting up and mixing

stubble or heavy crops with soil

ii. For primary tillage in orchards and vineyards as well as in open fields

iii. Lighter units used in seedbed preparation sub subsequent to plowing

3. Disk Harrow

a. Single Acting Disk Harrow- has two opposed gangs of disc blades, both throwing

dirt outward from the center of tilled stripb. Tandem Disk Harrow

- has two additional gangs that throw the dirt back toward the center as second operation, thus tilling the soil twice and leaving the field more level

c. Offset Disk Harrow- has one right hand gang (i.e a gang that moves the soil

to the right) and one left hang gang, operating in tandem

4. Cultivator• There are many different combinations of

frames and tines (or shovels)• The common types are the standard rigid

cultivators (with or without spring), light or heavy spring teeth, and heavy coil spring

• Cultivator with tooth equipment is used for weed controls, seedbed preparation and other secondary tillage operations

a. Spike Tooth Harrow– Used for finishing the seedbed by smoothing it and

breaking surface clods, particularly in mellow, friable soil

– Effective in killing small weeds– Covering broadcasted seeds– Breaking crusts that have formed over newly

planted crops

b. Spring Tooth Harrow– Has long curved teeth made from spring steel 6-8

mm thick and usually 19-25 mm wide– Used in rough or stony ground– Useful for loosening and bringing roots of certain

obnoxious grasses and weeds to surface– For bringing clods to surface for pulverization

c. Ridgers– Comes under field cultivators– To make a ridger, a moldboard disk can be used

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