REVIEW OF

LITERATURE

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REVIEW OF LITERATURE

Sustainable development has caught the imagination and action all over the world for

more than a decade. Sustainable agriculture is necessary to attain the goal of sustainable

development. According to the Food and Agriculture Organization (FAO), sustainable

agriculture “is the successful management of resources for agriculture to satisfy changing

human needs while maintaining for enhancing the quality of environment and conserving

natural resources”. Organic farming is one of the several approaches found to meet the

objectives of sustainable agriculture. Adverse effect of modern agriculture practices not only

on the farm but also on the health of all living things and thus on the environment have been

well documented all over the world. Organic farming is one of the widely used methods,

which are thought of as the best alternative to avoid the ill effects of chemical farming. The

origin of organic farming goes back, in its recent history, to 1940s. During this period, the

path breaking literature on the subject published by J.I. Rodale in the United States. Lady

Balfour in England and Sir Albert Howard in India contributed to the cause of organic

farming (Narayan, 2005).

Most of the apple nurseries are at the altitude between 1,200-2,700 m above mean sea-

level in the Himalaya ranges. Apple cultivation requires 1,000-1,500 hours of chilling

below 7⁰C during winter to break the rest period. Soil depth, drainage and pH determine

the suitability of soil types. Loamy soils, rich in organic matter having a pH of 5.5-7.5

with gentle to moderate slope, proper drainage and good aeration are most suitable. The

soil should be free from hard substrata and waterlogged conditions. Where cultivation is

done on flat soils, proper drainage channels need to be developed to restrict the incidence

of soil-borne diseases. The average summer temperature should be around 21-24⁰C

during active growth period. In winter the average temperature should not exceed the

chilling requirement i.e. below 7⁰C. The areas of rainfall of 100-125 cm through the

growing season is most favorable with frost-free spring and adequate sunshine during

summer without wide fluctuations in temperature are most suitable for apple nursery

production (Kishore et al., 2011).

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Farmers in Krishna District, Andhra Pradesh do not use chemical fertilizers.

Pesticides are anathema to them. All the inputs needed for cultivation are available in

the farm. They wait for the right planetary positions to spray solutions developed

from organic materials for the healthy development of the plants. They irrigate crops

with energized water. These are the biodynamic farmers, a new breed in Krishna

district, which has a long history of progressive farming. Biodynamic agriculture is

based on the teachings of German scientist Rudolf Steiner. He delivered eight lectures

in 1924 that made the world sit up and notice him, says biodynamic farmer Chalasani

Dutt. How is water energized by circular compartments? The water released into the

circular compartments circulates in a specific direction and moves into the tank. The

water so collected is used for farming as it is considered to have been energized, says

Mr. Dutt. Industrialist-turned-horticulturist Mr. Dutt began experimenting with

organic farming a few years ago in his garden at Vattigudipadu village in Krishna

district. He says he shifted to biodynamic farming as it involves "zero tillage and zero

external input" and is eco-friendly, too. What homoeopathy is to medicine is

biodynamic farming to agriculture. Steiner had described the way to make eight

preparations that were either sprayed on to the plant directly or used in the

preparation of compost. "Composting is an art which takes time to learn. It can be

mastered only with continuous practice." He says farmers in Krishna could benefit

vastly by practicing biodynamic farming. He says that he is doing sub-soil water

harvesting along with rainwater harvesting (Rao and Ramana, 2006).

Save (1992) found that after three years of switching over to natural cultivation, the soil

was still recovering from the after effects of chemical farming .When the soil regained its

health production increased and the use of inputs decreased. The farm which was yielding

200 to 250 coconuts per tree gave 350 to 400 per annum.

Rahudkar and phate (1992) narrate the experience of organic farming in Maharashtra.

Individual farmers growing sugarcane and grapes after using vermi-compost saw the soil

fertility increased irrigation decreased by 45 per cent and sugarcane quality improved.

The authors say that net profits from both the sugarcane and grape crops are high in

organic farms.

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Bernard (1999) has of the opinion that there is no other farming method so clearly

regulated by standards and rules as organic agriculture. The organic movement has

decades of experience through practicing ecologically sound agriculture and also in

establishing inspection and certification schemes to give the consumers the guarantee and

confidence in actually. Organic farming reduces external inputs and it is based on a

hostile approach to farming. He describes the worldwide success stories of organic

farming base on the performance of important countries in the west. The magnitude of

world trade in organic farming products is also mentioned .To the question of whether the

organic farming can feed the world, he says that neither chemical nor organic farming

systems can do it; but the farmers can.

The formation of the International Federation of Organic Agriculture Movements

(IFOAM) at Versailles, France, in 1972 set organic food and farming on a strong future

trajectory. It secured „organic‟ as the core narrative element and as the international

descriptor of what is now a clearly identifiable and differentiated segment of the global

food and farming sector. From the outset „biodynamic‟ was accepted as a special case of

„organic‟. The formation of IFOAM created an entity which united the aspirations, the

philosophies and the hopes of disparate groups each with roles primarily restricted to

national advocacy. IFOAM has grown to a federation of 804 organizations from 111

counties. Organic production statistics are now reported by IFOAM from 154 countries

and organic sector retail sales are reported to be US$51b annually. IFOAM is based in

Bonn, Germany, and as the global umbrella advocacy group for the organic sector it is

without peer (Paull, 2010).

According to Steiner (1993) the clay is the mediator between calcium and silica process.

The clay soil can therefore be used as one of the source materials in Biodynamics for

BD500 preparation. The plant material such as flowers from compositae such as Tridex

procumbens, Ageratum conzyzoides and leaves of Casuarina sp. were explored for its

potentials in biodynamic (Perumal and Vatsala, 2002).

Porebski et al., (2003) observed in field experiments that the application of organic

amendments such as peat, humus and cow dung improved the diameter of trees and

increased the number and length of shoots. Ammonium phosphate and captan had no

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positive effects on the growth of the trees.

Marangoni et al., (2005) considered the Physical, chemical and biological effects of

humus or secondary components resulting from decomposition of the organic matter

(residues of animal and plant origins at different stages of development) on soil quality.

An illustration was also included on the process of cork development in roots.

Investigations were conducted in Emilia Romagna, Italy, to study the effect of mineral

and organic fertilizers on development of peach and apple. Cow manure gave the greatest

cumulative length of roots (371 cm/plant), compared with the lower dose of mineral

fertilizer (298 cm/plant), the higher dose (244 cm/plant), the control without fertilizers

(241 cm/plant) and lime + molasses (213 cm/plant). Fruit from plants treated with

mineral fertilizers had the highest amount of total amino acids and higher content of

glutamic acid compared with that obtained with manure or in control. Fruit from plants

treated with manure had higher content of lysine.

Sanchez et al., (2006) evaluated the effects of soil management on yield,

growth and soil fertility in an organic apple orchard cv. Royal Gala/EM 26 and cover

crop treatments were applied to the inter-row spaces planted at 4x2 m. Soil organic

matter increased in the topsoil especially with permanent cover crops but decreased in the

C treatment due to both annual soil tillage and less input of groundcover biomass. It is

concluded that tree growth and yield are affected by soil management. Perennial cover

crops perform better than annual common vetch. Disking is not a recommended practice

because it may decrease the content of soil organic matter and lead to poor tree vigor that

corresponds to low fruit bearing potential. However, even with the use of permanent

cover crops the addition of organic fertilizers is necessary in order to sustain good yields

and proper tree vigor.

Verma et al., (2009) investigated that the improvement in soil moisture availability, pH,

organic carbon and nutrient status of the soil was significant under organic

manure. Growth parameters, fruit characteristics and yield were recorded maximum with

application of organic manure.

The study to assess the effects of integrated, organic, and conventional apple

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(Malus x domestica [Malus pumila] cv. Golden Delicious) production systems on

horticultural performance, soil quality, and orchard profitability indicated that the

integrated and organic production systems maintained higher soil quality than did the

conventional system (Andrews et al., 2001).

Soil moisture, pH, organic carbon and available N, P and K were recorded maximum under the

application of commercial organic manure @ 20 kg tree-1 treatment and Farm yard manure @

100 kg tree-1 during 2004 and 2005. Better quality apple fruits were also obtained under the

application of commercial organic manure @ 20 kg tree-1 and Farm yard manure @ 100

kg tree1 during both the years of experimentation (Verma et al., 2010).

Soil tests indicate that some of the organic orchards (and one of the conventional) have nutrient

deficiencies requiring significant annual additions; about half the organic orchards sampled

were P and K deficient. Nitrogen, calcium, and iron levels were low in leaf tissue sampled from

weak trees growing where sod was dominant, compared to that sampled from strong trees

growing where sod growth was minor. The problems observed in the organic apple orchards

appear to be related to orchard floor management. Competition between the apple trees and the

sod for available nutrients, particularly nitrogen, is most likely the limiting factor

affecting tree growth and production (Voroney et al., 2007).

Bozkurt et al., (2010) indicated that repeated sewage sludge application to apple trees did

not cause toxicity in leaves and fruits. However, long-term sewage sludge application

may result in the accumulation of Zn, Cu and Ni in the soil and plant.

Rifai et al., (2000) evaluated that mulching was a very good alternative method to

herbicide use and the best results of weed control were obtained in the following order:

saw dust-coarse bark-hay (weed reductions were as high as 99,4% with saw dust, 99,3%

with coarse bark and 96,0% with hay).

Wani et al., (2009) evaluated the effects of various herbicides on weeds

infesting apples in the nursery. The treatments included diuron at 1.5, 2.0 and 2.5 kg/ha,

glyphosate at 1.0, 2.0 and 2.5 litres/ha, atrazine at 1 and 2 kg/ha, hand weeding (two

weeding at 30-day intervals) and untreated control. Results showed that all herbicide and

hand weeding treatments reduced the weed population in comparison to the control.

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Apple seedling growth was highest under glyphosate treatment, which may be due to the

lower weed population under these treatments. Among the herbicides, the highest

mortality (62.97 and 60.99%) of apple seedlings due to phytotoxic effect was recorded

with atrazine at 2.0 and 1.0 kg/ha, respectively.

Vermicomposts are prepared from different types of leaves litter of horticulture and forest

plant species by modified vermicomposting process at a farm unit. The physico-chemical

characteristics, enzyme activities (oxido-reductases and hydrolases), and microbial

population (bacteria, fungi, free-living nitrogen-fixing bacteria, actinomycetes, Bacillus,

Pseudomonas, phosphate-solubilizing bacteria and fungi) of vermi-composts were found

significantly higher (p %3C 0.05) than those of control (without earthworm inoculums).

Srivastava et al., (2011) studied significant contributions of earthworm culture to

physico-chemical, enzymatic, and microbiological properties of vermicompost and

confirmed superior fertilization potential of vermicompost for organic farming.

Manivannan et al., (2009) showed that the application of vermicompost @ 5 tonnes/ ha

had enhanced significantly the pore space (1.09 and 1.02 times), water holding capacity

(1.1 and 1.3 times), and cation exchange capacity (1.2 and 1.2 times). It reduced particles

(1.2 and 1.2 times), and bulk density (1.2 and 1.2 times), pH (1 and 1.02 times) and

electrical conductivity (1.4 and 1.2 times) and increased organic carbon (37 and 47

times), micro (Ca 3.07 and 1.9 times, Mg 1.6 and 1.6 times, Na 2.4 and 3.8 times, Fe 7

and 7.6 times, Mn 8.2 and 10.6 times, Zn 50 and 52 times and Cu 14 and 22 times) and

macro (N 1.6 and 1.7 times, P 1.5 and 1.7 times, K 1.5 and 1.4 times) nutrients and

microbial activity (1.4 and 1.5 times) in Clay loamy soil and sandy loamy soil types,

particularly more in clay loamy soil. On the other hand, the application of inorganic

fertilizers @ 20:80:40 kg ha -1 has resulted in reduced porosity (1.03 and 1.01 times),

organic carbon (1.04 and 9.5 times) and microbial activity (1.02 and 1.03 times) in both

soil types.

The microbial biomass in the soil is made up of bacteria, fungi actinomycetes, algae,

protozoa and nematodes and it contributes 25% of the total biomass on earth (Gupta, 1998).

The microbial biomass contributes to the maintenance of soil fertility and soil quality in both

natural and managed soils. The microbial biomass is a part of the soil organic matter. It plays

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a major role in the development and functioning of terrestrial ecosystem. In both undisturbed

and cultivated systems, potential productivity is directly related to soil organic matter

concentration and turnover. It is a complex mixture of living, dead, decomposing material,

and inorganic compounds (Smith et al., 1993).

Yao et al., (2005) mentioned in their study that rootstock genotype was the dominant

influence on root lifespan and distribution whereas preplant soil fumigation,

compost amendments, and replanting positions had little apparent impact on root

characteristics despite their influence on above-ground tree growth and yield.

The effects of various nonfumigant planting-hole treatments on growth and yield of apple

(Malus X domestica Borkh.) trees were measured during the first 3 years after planting.

Eight orchards diagnosed as having a replant problem were monitored. First-year

shoot growth, the number of blossoms in the second year (in most orchards), and first-

year trunk cross-sectional area increment (TCAI) in 50% of test orchards were increased

by monoammonium phosphate (MAP) fertilizer + peat, MAP + mancozeb, or MAP +

peat + a bacterial antagonist. By the end of year 3, TCAI generally was not affected by

treatments, but treatments resulted in more blossoms by the third season in two of seven

orchards that blossomed in the second season. Cumulative yield after 3 years increased

significantly in only three orchards, with the best treatment, MAP + peat, resulting in cost

recovery in only one orchard. Inadequate K or Cu nutrition may have reduced growth in

some of the orchards, which were characterized by a wide range in yields, independent of

planting-hole treatment (Neilsen et al.,1994).

Marino et al., (2006) investigated the effects of different aqueous extracts of organic

waste compounds on growth, proliferation and photosynthetic activity in 'M9'

(Malus x domesticaz Borkh.) shoot cultures, with the aim of determining the feasibility of

using in vitro cultures as a tool for the rapid evaluation of organic amendments in

agriculture. Aqueous extracts of the following organic waste compounds: cow manure

(CM), sugarbeet industrial waste (SB), mixed grape, poultry and municipal solid waste

(GPM), and citrus pruning and industrial waste (CPI) were prepared at a rate of 1:10

(w/v) compound:distilled water. The basal media used in the proliferation phase were: (i)

PM1, modified Murashige and Skoog (MS) enriched with 4.4 micro M 6-benzyladenine

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(BA); (ii) PM2, as PM1 but with a reduced cytokinin concentration (1 micro M BA) to

evaluate possible hormone effects; and (iii) PM3, 4.4 micro M BA with reduced salt

strength (0.33 x MS) to induce nutrient deficiency. Hormone-free medium with half-

strength MS salts was used for rooting. All media were enriched with each extract at 0,

0.2, 2, 20 or 200 ml l-1

. Photosynthetic activity was measured on PM3 medium enriched

with SB or CM. Standard culture conditions were 22 degrees +or-2 degrees C, with a 16

h photoperiod at 30 micro moles photosynthetically active radiation (PAR) m-2

s-1

, but at

80 micro moles PAR m-2

s-1

to determine photosynthetic activity. Shoot weight increase in

PM1 was not affected by the GPM and CPI extracts, while the growth trends of CM- and

SB-treated shoots were described by a second-degree function with maxima at 2 ml l-

1 and 0.2 ml l

-1, respectively. Shoot proliferation for SB was represented by a quadratic

curve (maximum at 2 ml l-1

), was linearly reduced as GPM increased, but was not

affected by CM or CPI. Treatments did not significantly affect rooting percentage and

root length; however root number was increased by SB at 2 ml l-1

. CO2 fixation increased

linearly with both SB and CM, despite reduced growth at the highest levels of extract.

To investigate the effects of the application of apple pruning‟s compost on the growth of

apple nursery trees and on the chemical properties and aggregate structure of soil, three

kinds of composted apple pruning were applied by Sakamoto et al., (2010) to soil in

Wagner pots planted with apple nursery trees. They evaluated that the application of

composted apple pruning promotes the growth of apple nursery trees and is an effective

method of improving the chemical properties of soil.

Soil cover is one of the options for weed management in the orchard but this might affect

fruit trees development. Pelizza et al., (2009) evaluate apple trees growth during the

orchard establishment stage by using different materials and soil cover plants.

The apple tree height and diameter decreased with the increase of soil cover by weeds,

reflecting weeds competition with apple trees.

Replanting had a negative effect on the development of apple tree propagation material in

the nursery. Kviklys et al., (2008) investigated soil exhaustion and rootstock effect on

the growth of apple planting material and resulted that bud survival of cv. 'Sampion'

decreased by 24% compared to those in fresh soil. Other tree growth parameters were

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suppressed as well: tree height by 29%, trunk diameter by 24% and average leaf area by

28% and absolutely dry leaf weight by 33%. Combining all parameters it could be

concluded that apple trees of cv. 'Sampion' on P 59 and P 60 rootstocks are the most

sensitive to soil exhaustion, whereas trees on P 2 and B.396 rootstocks show tolerance to

replanting.

Specific apple replant disease causes reduced growth, impaired productivity and poor

economic performance of new apple orchards planted on land that previously grew apples

(Tustin et al., 2008).

A study was conducted (El-Motaium, 2007) to investigate the possibility of using

composted municipal solid waste (MSW) as the main fertilizer for 4-year-old apple (cv.

Anna) trees grafted on Mailing Merton 106 rootstock and grown on sandy soil at the

Plant Research Department Experimental Farm, Atomic Energy Authority (Egypt) to

substitute for mineral fertilizers, and determine the MSW effect on the tree nutritional

status, growth and fruit quality. The results indicate that the application of MSW to

sandy soils improved its physical and chemical properties, provided the soil and plant

with nutrients, and increased the yield compared with the control (mineral fertilizers).

Significant increase in tree growth (shoot length, trunk diameter), number of buds

formed, fruit set and leaf chlorophyll content occurred as a result of using MSW

compared with the control. The nutritional status of the tree (N, P, K, Ca, Mg, Fe, Mn, Zn

and Cu) in leaves and fruits showed sufficient concentrations of macronutrients and

micronutrients for adequate tree growth. Heavy metals in leaves and fruits were far below

the toxic limits compared with the international standard. Improved fruit quality was

obtained under MSW fertilizer treatments. Composted municipal solid waste has

provided apple trees with their essential nutrients. The higher MSW application rate

(200% N requirement) recorded higher fruit yield than the lower MSW application rate

(100% N requirement) and the control.

Utkhede (1999) tested twenty-three strains of Bacillus subtilis in sandy loam soil in field

experiments in 1992. The roots of 1-year-old McIntosh apples on a M.26 rootstock were

dipped in bacterial suspensions for 5 minutes before planting. Trunk diameters were

measured in autumn 1995 and compared with 1992 measurements. Nine B.

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subtilis strains significantly increased trunk cross-sectional area of apple seedlings in the

problem soil.

Organic fertilization and soil management can interfere directly on yield and growth of

apple trees, especially in shallow soils. The application of litter poultry promoted the

recovery of plant growth and in a more efficient way when herbicide was used as weed

control (Nava, 2010).

Zhao (2010) concluded that sandy soil localized fertilized with adequate amount of

organic manure can control the growth of shoots and roots. Fruiting and fresh weight of

the fruits depended on the weather conditions (Pakula et al., 2006).

Changes in the composition of soil microbial communities and relative disease-

suppressive ability of resident microflora in response to apple cultivation were assessed

(Mazzola, 1999) in orchard soils from a site possessing trees established for 1 to 5 years.

The fungal community from roots of apple seedlings grown in noncultivated

orchard soil was dominated by isolates from genera commonly considered saprophytic.

Plant-pathogenic fungi in the genera Phytophthora, Pythium, and Rhizoctonia constituted

an increasing proportion of the fungal community isolated from seedling roots with

increasing orchard block age. Bacillus megaterium and Burkholderia cepacia dominated

the bacterial communities recovered from noncultivated soil and the rhizosphere

of apple seedlings grown in orchard soil, respectively.

Soil fungal community composition under the Mulch differed from that under other

treatments. The effects of groundcover management system on soil microbial community

abundance, activity, and composition were associated with observed differences

in soil organic matter inputs and turnover, nutrient availability, and apple tree growth and

yields under the different groundcover management system treatments (Yao et al., 2005).

The treatment of apple seeds with charcoal-based inoculant of Bacillus megaterium, a

plant growth promoting rhizobacterium originally isolated from roots of apple seedlings,

significantly increased the various growth attributes of 6-month-old apple seedlings under

unsterilized soil conditions. The effect of seed treatment was more pronounced when jaggery

was used as adhesive and seed treatment was given after stratification. The percent increase

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in shoot length, shoot dry weight, root length and root dry weight ranged from 32.04 to

62.12% over the untreated control. The rhizosphere soil bacterial population and

rhizobacterial population of apple seedlings were positively and significantly correlated with

the above mentioned parameters. Similarly, nitrogen (1.15-2.72%), phosphorus (0.13-0.36%)

and potassium (1.21-1.92%) contents of whole shoot system were more in bacteria-treated

seedlings than those not treated with the bacterium (Shirkot and Sharma, 2002).

Perumal et al., (2006) explored the presence of plant growth hormones in selected

organic manures. Twelve types of organic manures such as vermicompost, NADEP

compost, cow pat pit (CPP), biodynamic compost, cow horn manure (BD 500),

biodynamic herbal preparations such as BD 502 to 507 were collected from Shri AMM

Murugappa Chettiar Research Centre, Tharamani and Kurinji Organic Food Pvt. Ltd.,

Genguvarpatti Tamil nadu. Among the 12 organic manures analyzed for the enumeration

of microorganisms, cow pat pit manure contained highest bacterial load (4.5x 106) and

beneficial bacteria such as Rhizobium sp. (1.9x106), Azospirillium sp. (0.2x10

6) and

Azotobacter sp . ( 0.8x106). All the 12 organic manures were analyzed for the presence of

plant growth hormones such as indole acetic acid (IAA), gibberillic acid (GA3), kinetin

and abscissic acid (ABA) found that there were appreciable differences in the content of

plant growth hormones. The cow pat pit manure contained three plant growth hormones

such as IAA (28.6 mg/ Kg of manure) and kinetin (7.6mg/ Kg of manure) and Gibberllic

acid (23.6 mg/ Kg of manure) whereas the other manures did not contain Gibberlic acid.

Biodynamic herbal preparations BD 504, BD 505 and BD 506 contained IAA, GA3 and

abscissic acid (ABA). The anatomical structure of onion root grown in CPP had 2

metaxylem whereas the others had only one metaxylem.

Seventeen nurseries in England were surveyed for crown gall (Agrobacterium

tumefaciens).The presence or amount of crown gall could not be related to type of bed, to

age of bed, to soil pH or to type of loam or silt soil (Lelliott, 1971).

All cultivated and natural un-disturbed soils were generally good in organic contents. Their

nutrient status was also well within the range of good quality soil. The garden soil was low to

very low in organic contents and needed organic supplement. The soil quality was very poor.

The higher organic content was associated with higher fungal diversity and population levels

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in most of the samples. Quality of poor soil can be altered by enriching and modifying the

microbial flora of the soil (Wahegaonkar et al., 2009).

The effects of Contact and residual herbicides, polypropylene woven (plastic) and straw

mulches treatments on weed control, soil quality, tree nutrition, tree growth, crop yield and

fruit quality were measured as ground vegetation management systems (Hipps et al., 2004).

Contact herbicides gave the poorest weed control, followed by residual herbicides. Very

little weed intrusion occurred in the plastic and straw mulch treatments. The concentrations

of soil biomass C, biomass N and respiration rates were consistently greatest under the

straw mulch and contact herbicide, suggesting that C and N was incorporated into

the soil biomass most efficiently under these treatments. The trees in the straw mulch had

the greatest yields and mean fruit weights. The ground vegetation management systems did

not influence fruit quality except in the second harvest, when yields were low and the

individual fruits were large.

Wang et al., (1997) observed that soil humus content, water content and texture were the

key factors affecting rootlet growth, and soil Cu, B and Fe also strongly affected

root growth. Soils with 29.5% viscid particles and 29.3% gravel were of optimum texture

for root growth.

Sakamoto et al., (2010) investigated that the application of composted apple pruning

promotes the growth of apple nursery trees and is an effective method of improving the

chemical properties of soil.

Mulching the soil with the pine bark resulted in higher increases in the yield of apples

and growth trees (Kawecki et al., 1999).

The orchard soil management practice i.e. herbicide plus mulching with hay resulted in the

greatest fruit length (7.20 cm), fruit breadth (7.48 cm) and fruit weight (260.4 g) followed by

mulching with hay. The smallest fruit length (6.78 cm), fruit breadth (6.97 cm) and fruit

weight (232.6 g) was observed with clean cultivation (Rehalia et al., 1999).

Mechanical cleaning to the middle of the alleyways, tree row weed control using Humus

or soil covering with straw gave the highest yield and marketable fruits. A one meter

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weeded strip in the tree row did not remove the competition of the clover grass alleyway.

Natural vegetation (weed) in the tree row reduced the yield with more than 50%

(Pedersen and Pedersen, 2004).

The systematic use of nitrogen fertilizers (N (sub) 90-120) contributes to mineral nitrogen

and humus accumulation in a one meter soil layer, increase in the output of green manure

mass. As a green manure winter rye is recommended this gives 10 t/ha of dry matter

(Vasilenko, 1996).

Hoagland et al., (2008) concludes that meeting the multiple objectives of weed control,

optimal tree health, and increased soil biological activity may require employment of

different orchard floor management strategies at different times during the life of the orchard.

Howlader et al., (2008) carried out an incubation experiment in a laboratory at room

temperature (28+or-4 degrees C) for 60 days with four organic materials to assess

the biodynamics of microbial biomass nitrogen and sulfur. The organic materials were

dustbin waste, poultry litter, sewage sludge and rice straw. The organic materials were added

at a ratio of 2% to the soil. A basal dressing of 200 micro g P and 250 micro g/Kg soil in the

form of KH2PO4 was applied to each treatment, except for the control. The highest rate of

CO2-C evolution was observed in the rice straw amended soil, which was significantly higher

than that of poultry litter, dustbin waste, sewage sludge treated soil and control. Rice straw

contributed the highest amounts of biomass-C, -N and -S which were significantly higher

than that of poultry litter, dustbin waste and sewage sludge amended soils. The soils amended

with sewage sludge, dustbin waste and poultry litter showed N and S mineralization whereas

soil amended with rice straw induced N and S immobilization.

The module comprising of soil application of neem cake with Ttrichoderma @ 8kg/ha

and foliar spray of neem formulation (azadirachtin) was found effective for organic pest

and disease management in fenugreek. Root rot of 6 to9% was recorded in this treatment

while aphid infestation was also found low (137). Powdery mildew was also observed at

21.45 and 26.78%at 70 and 100 DAS, respectively (Chhata and Verma, 2010).

Hassan et al., (2009) inoculated one-year old apple seedling of cv.‟Red Delicious‟ with

biocontrol agents viz., Glomus mosseae (an endomycorrihza), Laccaria laccata (an

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ectomycorrhiza) and Trichoderma harzianum ( a fungal antagonist) in presenceof root rot

pathogen, Pythium ultimum, to assess their impact on seeding growth and disease control. All

the biocontrol agents significantly enhanced plant height, seedling diameter, root length and

plant biomass as compared to uninoculated or pathogen- inoculated controls. Maximum

increase, in above parameters, was observed in Glomus compared to inoculated seedlings.

The disease severity in biocontrol agents-inoculated seedling ranged from 19.2 to 24.9 per

cent as compared to 52.4 per cent in pathogen-inculated control.

Salam et al, 2009 conducted on the use of medicinal plant leaf extract have opened a new

avenue for the control of plant disease. Medicinal plants are known to possess of various

types of alkaloids with varying solubility in different solvents. These alkaloids are

believed to have fungicitoxic properties. An effort was made to evaluate these alkaloids

extracted from datura, neem, lemon grass, Karanj and Calotropis procera. It concluded

that the cold water, hot water and acetone extracts from these plants used to reduce sheath

blight disease severity on rice.

Effect of integration of cultural, chemical and biocontrol and methods was studied on the

incidence of white root rot of apple caused Dematophora necatrix to devise a suitable

management strategy in nursery (2008). In pot culture (2007), all the combination gave

cent per cent disease control, and no disease incidence was recorded even after 60days of

inoculation. However, under nursery conditions, maximum disease control was recorded

in a combination of deodar needles+ neem cake +carbendzaim (0.1%) +Trichoderma

treatment. All the combinations were effective plant improving plant health expect the

individual treatments in pot culture. In addition, all treatments were at the same time

effective improving the plant health under nursery conditions (Rana et al., 2010).

Raj and Sharma, (2009) conducted experiment to integrate soil solarization with native

isolates of Azotobacter chrococcum and vesicular-arbuscular mycorrhizal fungi and

observe its effect on the incidence of white root rot and growth of the

saplings. Soil solarization with transparent polyethylene mulch (25 micro m thick) for

40 days in summer months resulted around 9 degrees C higher temperature with average

maximum temperature of 38-39 degrees C. Integrated Solarized soil was found most

effective with no incidence of white root rot in comparison to 33.6-35.4% in control

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accompanied with 78-113% increase in shoot length and 81.6-84.3% increase in root

length. Shoot and root length of the saplings was 9.6-10.6 and 9.2-16.0% higher,

respectively, in solarized plots in comparison to chemically sterilized plots.

A close correlation was observed between the growth of Spartan apples on M.26 rootstock

using soil that was steam heated in the planting site and the growth of apple seedlings in

greenhouse pot tests using site replant soil that was pasteurized separately at 77 degrees C for

1h. Trees in the pasteurized soil grew 94% more than the controls, showing the pot tests to be

good indicators of field response to heat treatment (Moyls et al., 1994).

Shatat et al., (2003) concluded that the trees of the three deciduous species: apple, peach

and grape failed to survive post plant solarization if the bare-rooted nursery stock was

used as planting material. On the other hand, apple trees were able to

survive soil solarization if container-grown trees were used at planting.

Field experiments were conducted in Solan, Himachal Pradesh, India, in 2001, to

determine the effect of soil solarization on the management of soilborne pathogens in

apple nurseries. Soil solarization with single and double layer transparent

polyethylene sheet (25 micro m) increased the soil temperature by 10.55 and 6.63

degrees C, respectively, at 10 cm and the increase in temperature at 30 cm soil depth

was comparatively less. All 3 soilborne pathogens (Dematophora necatrix [Rosellinia

necatrix], Sclerotium rolfsii [Corticium rolfsii] and Phytophthora cactorum),

infecting apple nurseries were killed up to a 30 cm depth after 60 days with double

and single layer polyethylene sheets. However, they remained viable in

unsolarised soil. High temperature under tarps had lethal effects on total microbial

population, but the population of antagonistic microorganisms increased

after solarization. Chemical characteristics of soil such as available nitrogen,

potassium, phosphorus and organic carbon contents increased after solarization

(Sharma and Sharma, 2005).

Soil solarization for 12 weeks resulted in maximum reduction in the population of fungi,

bacteria and actinomycetes, at 5, 10 and 15cm depths with 19.56, 35.00 and 40.00 per

cent survival of Dematophora necatrix propagules at these depths, respectively. Hence,

20

soil solarization carried out for longer durations can be utilized for soil borne disease

management in temperate regions (Sharma et al., 2005).

The use of farm, industrial, and consumer waste by-products as amendments in nursery

substrates has been a major focus. Chong (2005) has evaluated hundreds of potting mixes

derived from individual or combined, raw or composted waste by-products including

spent mushroom compost, turkey litter compost, paper mill sludge, municipal waste

compost, corrugated cardboard, apple pomace, wood chips from pallets, pulverized glass,

and various types of tree barks. With few exceptions, all the above waste by-products

tested under our cultural conditions provided acceptable to excellent container-growing

media, often in amounts exceeding 50% and sometimes up to 100% by volume in No. 2

containers (6 L), even despite initially elevated and potentially toxic contents of soluble

salts [expressed in terms of electrical conductivity measured up to 8.9 dS.m(-1) in 1

substrate:2 water (by volume) extracts] in many of the substrates. A key to these

successful results is that salts leach quickly from the containers to benign levels

(approximately 1.0 dS.m(-1)) with normal irrigation practices. High initial pH in most

waste-derived substrates (up to 8.9) has had little or no discernible effect on growth of a

wide assortment of deciduous nursery species. By-products such as paper mill sludge and

municipal waste compost with soluble salts contents typically ranging from 0.8 to 2.0

dS.m(-1), also provide acceptable rooting media provided salts are leached before use to

values less than or equal to 0.2 dS.m(-1). The porosity and aeration characteristics of

waste-derived substrates tend to be comparable to, or better than, those of bark.

The electric conductivity is the capacity of a material in driving electric current and one

of its usefulness in the agriculture comes from the fact that the soil electrical conductivity

(EC) varies with its intrinsic physicochemical variability. Molin et al., (2011) in their

study clearly indicated that EC relates with soil texture and moisture, and may represent

an important and low price tool for collecting data and characterizing soil physical

properties.

By knowing the electrical conductivity of their soils, farmers can make more precise

management decisions about fertilizer applications, irrigation, use of nematicides, and

other pesticide applications, according to Clemson University researcher Ahmed

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Khalilian. Though it sounds high tech, and the science behind it has been, the use of

electrical conductivity, or EC, is really an extension of the good old common sense

farmers have been using for thousands of years (Roberson, 2006).

Colete et al, 2005 studied the relationship between the electrical conductivity test and the

seedling emergence of soybean in field and laboratory. Germination and seedling

emergence decreased as the substrate water potential was reduced, indicating a

relationship among the germination, water potential and seed vigor. The electrical

conductivity test may be efficient to evaluate soybean seed vigor and, consequently, the

performance potential in the field. However, further studies are necessary to determine

the values or the range of values that indicate the seed vigor level and the adequate use of

a given seed lot.

The hypothesis that the form of N (NO3- or NH4

+) affects the pH of root/soil interface

depending on the soil buffering capacity was investigated (Tagliavini et al., 1997).

Rhizosphere pH was not affected by the fertilizer type in the silt loam but in the sandy loam it

averaged 4.7 and 5.6 with NH4+ and NO3

-, respectively. The strongest acidification at root

level was found in the silt loam in spite of its higher buffering capacity. The NH4+ fertilizer

depressed bulk soil pH and enhanced leaf Mn concentrations to levels considered toxic to

apples, while CaNO3increased leaf Ca concentration.

Shoot growth increased with soil pH. The highest yield (boxes/tree) was obtained at pH

6.0-6.5 and the largest fruits were produced at pH 5.5-6.9. Low soil pH was associated

with high concentrations of Mn in the leaves and fruit and a reduction in fruit red skin

colour (Raese, 1995).

Measurement of pH, electrical conductivity (EC) parameters provides valuable

information for assessing soil condition for plant growth, nutrient cycling and biological

activity. Soil & crop management practices have significant effect on pH & EC are

considered good indicators of change. Elevated pH values can indicate potential losses of

nitrate & subsequent water contamination. The tendency for soil a acidification can

suggest insufficient use of ammoniac fertilizers increased leaching losses (Smith and

Dovan, 1996).

22

Mode of antagonism of Trichoderma viride against Alternaria triticina causing leaf blight of

wheat was studied in vitro by employing dual culture techniques as biocontrol agent.

Trichoderma viride inhibited the growth of the pathogen, its mycellial strands coiled around

the hyphae of the test pathogen forming a rope like structure & finally distintegrating the test

pathogen, Alternaria triticina (Praveen et al., 2004)

The soil is now believed to be a dynamic or rather a living system, containing a dynamic

population of organisms/microorganisms. Soil micro flora plays a pivotal role in

evaluation of soil condition and in stimulating plant growth (Singh et al., 1999).

Microorganism is beneficial in increasing the soil fertility and plant growth as they are

involved in several biochemical transformation and mineralization activities in soil. Type

of cultivation and crop management practices found to have greater influence on the

activity of soil micro flora (Mc Gill et al., 1980). As soil inhabit several diverse groups of

microorganisms, but the most important amongst them are: bacteria, actinomycetes, fungi,

algae and protozoa. Continuous use of chemical fertilizers over a long period may cause

imbalance in soil micro flora and there by indirectly affect biological properties of soil

leading to soil degradation (Manickam and Venkataraman, 1972). In soil and rhizosphere

region, many microorganisms live in close proximity and their interactions with each other

may be associative or antagonistic. Gibberellins and gibberellin- like substances are known to

be produced by bacterial genera viz Azotobacter, Arthrobacter,

Pseudomonas, and Agrobacterium which are commonly found in the rhizosphere.

Microorganisms also influence root hair development, mucilage secretion and lateral root

development. Fungi inhabiting the root surface facilitate the absorption of nutrient by the

roots. The mycorrhizal association has been found to improve plant growth through better

uptake of phosphorus and zinc from soil, suppression of root pathogenic fungi and

nematodes. Another example is association between the bacterium Rhizobium and roots

of legumes and Azospirillum with cereal crops (wheat, rye, bajara, maize etc).

Antagonistic microorganisms in the rhizosphere play an important role in controlling

some of the soil borne plant pathogens. Stanier et al., (1966) discovered the bacterial

strain Pseudomonas fluorescens and the fluorescent pigments of this species in biological

control of root pathogens. Strains of P. fluorescence are collectively called

as "Fluorescent Pseudomonads". They produce variety of biologically active compounds

23

such as plant growth substances, cyanides, antibiotics and iron chelating substances

called "Siderophores" Rovira and Campbell (1975) showed that bacterial strains of P

fluorescens could lyse the hyphae of Gaumannomyces graminis var. Tritici, the causative

agent of take-all disease of wheat. Fluorescent pseudomonads (P. fluorescens, P.

putida)are known to produce iron chelating substances called Siderophores. The

successful antagonists among fungi are Trichoderma sp (T. viride and T. harzianum, T.

hamatum) and Gliocladium virens which parasitize, lyse or kill the phytopathogenic fungi

in the soil. Respiration by the rhizosphere microflora may lead to the change in soil

rhizosphere PH. If the activity and population of the rhizosphere microflora is more, then

the PH of rhizosphere region is lower than that of surrounding soil or non-rhizosphere

soil. Rhizosphere effect for bacteria and protozoa is more in slightly alkaline soil and for

that of fungi is more in acidic soils. Organic Matter creates a granular condition of soil

which maintains favorable condition of aeration and permeability. It acts as a buffering

agent which checks rapid chemical changes in pH and soil reaction (www.agriinfo.in).

The activity of soil microflora (bacteria, actinomycetes and fungi) was comparatively

more in surface than in subsurface horizons and decreased with depth due to decrease in

organic matter. Similar kind of observations were also made by Bopaiah (1991), Dovan

(1980) and Gupta and Tripathi (1988) in their studies. .

Amongst the different microorganisms inhabiting in the soil, bacteria are the most abundant

and predominant organisms. These are primitive, prokaryotic, microscopic and unicellular

microorganisms without chlorophyll. Morphologically, soil bacteria are divided into three

groups viz Cocci (round/spherical), (rod-shaped) and Spirilla I Spirllum (cells with long

wavy chains). Bacilli are most numerous followed by Cocci and Spirilla in soil. As per the

system proposed in the Bergey's Manual of Systematic Bacteriology, most of the bacteria

which are predominantly encountered in soil are taxonomically included in the three orders,

Pseudomonadales, Eubacteriales and Actinomycetales of the class Schizomycetes. The most

common soil bacteria belong to the genera Pseudomonas, Arthrobacter, Clostridium,

Achromobacter, Sarcina, Enterobacter etc. The another group of bacteria common in soils is

the Myxobacteria belonging to the genera Micrococcus, Chondrococcus, Archangium,

Polyangium, Cyptophaga. All autotrophic bacteria utilize Co2 (from atmosphere) as carbon

source and derive energy either from sunlight (photoautotrophs, eg. Chromatrum.

24

Chlorobium. Rhadopseudomonas or from the oxidation of simple inorganic substances

present in soil (chemoautotrophs eg. Nitrobacter, Nitrosomonas, Thiaobacillus).Majority of

soil bacteria are heterotrophic in nature and derive their carbon and energy from complex

organic substances/organic matter, decaying roots and plant residues. Bacteria bring about a

number of changes and biochemical transformations in the soil and thereby directly or

indirectly help in the nutrition of higher plants growing in the soil (Baruah and Barthakur,

1997). Actinomycetes are clubbed with bacteria the same class of Schizomycetes and

confined to the order Actinomycetales. They are unicellular like bacteria, but produce a

mycelium which is non-septate (coenocytic) and more slender, like true bacteria they do not

have distinct cell-wall and their cell wall is without chitin and cellulose (commonly found in

the cell wall of fungi). On culture media unlike slimy distinct colonies of true bacteria which

grow quickly, Actinomycetes colonies grow slowly, show powdery consistency and stick

firmly to agar surface. They produce hyphae and conidia / sporangia like fungi. Certain

Actinomycetes whose hyphae undergo segmentation resemble bacteria, both

morphologically and physiologically. Actinomycetes are numerous and widely distributed in

soil and are next to bacteria in abundance. Actinomycetes belonging to the order of

Actinomycetales are grouped under four families viz Mycobacteriaceae, Actinomycetaceae,

Streptomycetaceae and Actinoplanaceae. Actinomycetous genera which are agriculturally

and industrially important are present in only two families of Actinomycetaceae and

Strepotmycetaceae. In the order of abundance in soils, the common genera of actinomycetes

are Streptomyces (nearly 70%), Nocardia and Micromonospora although Actinomycetes,

Actinoplanes, Micromonospora and Streptosporangium are also generally encountered.

Organic residues / substances added soil are first attacked by bacteria and fungi and later by

actinomycetes, because they are slow in activity and growth than bacteria and fungi (Aneja,

2003).

Fungi in soil are present as mycelial bits, rhizomorph or as different spores. Their number

varies from a few thousand to a few -million per gram of soil. Soil fungi possess filamentous

mycelium composed of individual hyphae. The fungal hyphae may be aseptate /coenocytic

(Mastigomycotina and Zygomycotina) or septate (Ascomycotina, Basidiomycotina &

Deuteromycotina). As observed by C.K. Jackson (1975), most commonly encountered genera

of fungi in soil are; Alternaria, Aspergillus, Cladosporium, Cephalosporium Botrytis,

25

Chaetomium, Fusarium, Mucor, Penicillium, Verticillium, Trichoderma, Rhizopus,

Gliocladium, Monilia, Pythium, etc. Most of these fungal genera belong to the subdivision

Deuteromycotina / Fungi imperfeacta which lacks sexual mode of reproduction. As these soil

fungi are aerobic and heterotrophic, they require abundant supply of oxygen and organic matter

in soil. Fungi are dominant in acid soils, because acidic environment is not conducive / suitable

for the existence of either bacteria or actinomycetes. The optimum PH range for fungi lies-

between 4.5 to 6.5. They are also present in neutral and alkaline soils and some can even

tolerate PH beyond 9.0. Number of soil fungi forms mycorrhizal association with the roots of

higher plants (symbiotic association of a fungus with the roots of a higher plant) and helps in

mobilization of soil phosphorus and nitrogen eg. Glomus, Gigaspora,

Aculospora,(Endomycorrhiza) and Amanita, Boletus, Entoloma, actarius (Ectomycorrhiza).

(Aneja, 2003)