CROP MANAGEMENT

Planting materials
Seed Certification Phases
Minimum Germination Percentage for Seed Certification
Maximum Permissible Moisture level for seeds
Minimum isolation requirements for seed production
Vegetative Propagation
             Leaf Cutting
             Stem Cutting
             Simple Layer
             Air Layer
             Tissue Culture
Fertilisers
            Chemical fertilizers
            Organic manures
            Bio-fertilizers
            Liming
Plant protection
            Cultural
            Chemical
                     Insecticides
                     Pheromones
                     Fungicides
                     Herbicides
                     Rodenticides
                     Handling and mixing
                     Field applications
                     Equipment cleaning and storage
                     Storage of chemicals
                     Preparing the sprayer
                     Disposal of pesticides and containers
Bio control
Integrated Pest Management (IPM)
Weed management
            Prevention
            Cultural
            Mechanical
            Herbicidal

Seed

Seed is a fertile and ripened ovule, which contains an embryonic plant, supplied with food storage tissues and surrounded by a seed coat. A seed strictly speaking is an 'embryo' a living organism embedded in the supporting or the food storage tissue. According to the Seed Act 1966, seed includes all planting materials such as seedlings, tubers, bulbs, grafts, etc.

Seed Technology - involves seed production, processing, storage testing and certification, marketing and distribution and the related research on these aspects. Seed production includes varietals development, evaluation and release of varieties.

Role of Seed Technology - improved seed - a carrier of new technologies a basic tool for secured food supply- the principal means to secure crop yields in less favorable areas of productivity - a medium for rapid rehabilitation of agriculture in areas of natural disaster - a 'national seed reserve stock' of seed is necessary to face such situations. Seed is the fundamental unit of crop production - Regarded as the most vital, basic and critical input in agriculture for increasing and sustaining agricultural production. The year in which the Royal Commission on Agriculture was constituted -1925. It emphasized the need for a separate organization in India to deal with seed distribution. This paved the way for the set up of the National Seed Corporation (NSC) in 1963. Coverage of high yielding varieties in Kerala -60.32% (1999-2000). Maximum coverage during Punja followed by Viruppu and Mundakan. The poor coverage is the non-availability of quality seeds of the High Yielding Varieties (HYV). In India seed production and distribution have become a well developed industry - involving an annual turn over of Rs.2200 crores - Public sector -Rs.55 crores (25%) - Private sector Rs.1320 crores (60%) - other unorganised sector Rs.330 crores (15%) India is exporting seeds worth of Rs.20 crores in an year.

Goals - To increase agricultural production through the spread of good quality seeds of HYVs. It aims at (1) rapid multiplication, (2) timely supply, (3) assuming high quality, (4) reasonable price.

Bases of a Seed Programme - (1) high level support, (2) productive plant breeding programme, (3) Co-ordinated effort.

History of development of Seed Technology

• First Five Year Plan (1951-56) - Distribution of improved seeds of food grains came into existence - seed distribution with subsidy.

• Second Five Year Plan (1956-61) - Improved seed was made as a basis for 10% additional food grain production - Production of foundation seeds - started seed production centers and seed stores.

• Third Five Year Plan (1961-66) - Released first four hybrids of maize in 1961 - necessitated a separate organization for seed production. Thus gave birth to NSC in 1963.

HYV was started during 1966 and there was high coverage of HYV seeds for food crops by 1968-69. The HYV Programme had an almost explosive effect on the seed industries and necessitated huge effort in seed production, processing, certification, testing and storage, seed distribution, etc.

Annual Plans (1966-69) - Seed Review Team - Constituted by Government of India in 1968- suggested to entrust the work related to production, processing and marketing of seed co-operative and private sectors - also NSC should assist State Government to constitute their own certification agencies. IV plan (1969-74) - In 1969 - Tara Development Corporation Ltd was started with the active involvement of GB Pan1 University of agriculture and technology - Growers participation as shareholders instead of contract system of seed production.

Seed Act 1966 came into force through out India from 1969
V Five Year Plan (1974-79) - Reviewed by National Commission on Agriculture - Many recommendations were made in 1976 - (1) Rigorous enforcement of Seed Act 1966; (2) National Registry of varieties - system by ICAR; (3) Departments of Agriculture - in the center and state should have three distinct wings each dealing respectively with (a) input aspect, (b) land enforcement (c) certification; (4) Grow-out tests should be made on integral parts of seed testing.

Generation concept of seed multiplication

NUCLEUS SEED - initial seed-small quantity from the originating plant breeder - for further multiplication to maintain the variety - multiplication by the supervision of the plant breeder or any other qualified plant breeder - genetic purity - 100%.

BREEDER SEED - progeny of nucleus seed multiplied by the breeder or by the institution - source for the foundation seed - genetic purity is 100%. Not subjected to certification. But monitoring by a team of exports - Golden Yellow colour tag.

FOUNDATION SEED (FS) - Progeny of Breeder seed production is supervised by certification agency. Minimum genetic purity 99%-white tag. Can be II stages. FS Stage FS Stage II and I. Stage II is only if Breeder Seed I in short supply. NSC, SDA and State Seed Corporation are involved in the production.

CERTIFIED SEED (CS) - Produced from FS, Seed Certification Agency certifies - supervising by seed certification agency, State Seed Corporation and NSC - subjected to one or more stage of production genuine shortage of FS. Such production does not exceed three generations beyond FS.1 Minimum genetic purity 98% - Tag colour Azure Blue. To maintaining genetic purity, Cs should be replaced every 4th season or 4th crop.

SEED CERTIFICATION

Purpose: To maintain and make available high quality seeds with genetic identify and purity - designed to achieve prescribed standards - legally sanctioned system for quality control during all stages of seed production. In India seed certification is a voluntary process - but labeling is compulsory.

NSC evolved the certification standards. The central seed committee approved these standards - the standards are includes in the Indian minimum seed certification standards published by Government to establish their own seed certification agencies. A statutory central seed certification Board co-ordinated the activities of State seed certification agencies. (Only those varieties, which are notified by central seed committee, are eligible for certification).

• Verification of seed source
• Verification and approval of seed fields prior to planting
• Inspection of seed crop in field to verify its conformity to the prescribed standards.
• Supervision of harvest and post harvest operations including processing and packing.
• Sampling and analysis of seeds to conform seed standards.
• Grant of certificate tags, lebelling and sealing.

Seed Certification standards.

(Source: Indian minimum seed certification standards 1971 - Central Seed Committee)

Truthfully Labeled Seeds (TLS)
Seeds of the varieties, which are not eligible for certification can be, produced as truthfully labeled seeds. The seeds should be labeled as follows:
(1) Kind, (2) variety, (3) Lot No, (4) Date of test, (5) Inert matter % (6) pure seed %, (7) Other crop seed %, (8)weed seed %, (9) Germination %, (10) net content, (11) sellers name and address, (12) if treated, any one of the following statements should appear in the label:

'Do not use for food, feed or oil purpose (or Poison)'. If the content of the container is less than 250gm or less, the items 5 to 9 may be replaced by the statement " The seed in this container conform to the minimum limits of germination and purity prescribed under the Act"

Storage of seeds

Storage problems arise when -

1. Low quality seeds are stored
2. Seeds are not adequately dried
3. Seeds are stored in poorly constructed godowns
4. Seeds are stored for a very long time.

Factors influencing loss of viability of rice.

(1) Moisture content, (2) temperature (3) relative humidity - are the main factors.

Moisture - 12% moisture content - no fungal mould grow.
At 13% MC mould grow.
At 15% to 18% MC - maximum fungal growth.
At 8% RH - stored pests survive but do not multiply.
At 14% RH-insects multiply and destroy seeds.
At 18-20% RH - heating of seeds due to heavy respiration - insects & moulds grow.
At 40-60% RH- seeds germinate.

Leaf Cutting

Many plants can be artificially cloned by leaf cuttings; species that work well include African violet (Saintpaulia), Peperomia, bryophyllum (Kalanchoe) and jade plant (Crassula). In this process a leaf (blade + petiole) is removed from the donor plant. The leaf is placed in moist soil or, perhaps, in water and placed in the light.
The leaf blade, as usual, produces IAA (auxin). This auxin is transported basipetally (down the petiole) as usual.

The IAA accumulates in the base of the petiole to the point that a callus tissue (tumor) forms. A callus is a mixture of meristematic cells and parenchyma cells. Since these cells do not have a determined fate, it is possible to influence these cells to differentiate in just about any direction.

The IAA continues to accumulate in the callus. The concentration rises to the point that roots are initiated on the callus.

The roots produce cytokinins (CK). This hormone is transported acropetally (away from the root tip, toward the callus). The cytokinin accumulates in the callus.
As the concentration of cytokinin accumulates in the callus, it stimulates shoot formation. The shoots then can grow up. In the end you have a shoot with roots...a whole plant!

In some plants, the callus sends up multiple shoots. In those cases, the gardener has to separate the individual plantlets before potting up the individual plants.
Obviously this process can be accelerated if the last centimeter of the petiole is dusted with a mixture of talcum powder and synthetic auxin (indole butyric acid) before the leaf is planted in the moist soil at the beginning. This mixture is often called "rooting hormone" and two leading brands of this are Rootone&174 and Hormodin&174.

Stem Cutting

Many species cannot be propagated from leaves alone. The leaf may root, but shoots do not form, or form so slowly that you do not dare wait for it. For such species, it may be possible to instead make a stem cutting. The process is very much the same, but is much faster due to the contributions of auxin from several leaves, and the contributions of photosynthesis in several leaves.

Generally the gardener cuts a short piece of stem (three or four internodes maximum). It does not have to include an apical meristem, but often it does. The leaves from the lowest node are torn from the stem. The basal end of the cutting may be dusted with rooting hormone (if needed or desired).

The several leaves remaining on the stem cutting all send IAA (auxin) down from the blade. This accumulates at the basal end of the cutting (along with any applied rooting hormone). The accumulated auxin stimulates formation of callus and ultimately roots.

Once we have a stem with roots, our plant has been cloned and the process is complete.

Simple Layer

A tip layer is a natural method of propagation in such species as black raspberry. A simple layer is fundamentally an artificially-forced tip layer. In many shrubs that cannot be cloned by leaf or stem cuttings, a simple layer may work well. Rather than making a single leaf or a small stem cutting provide for its own needs and enough extra to make a new plant, a simple layer can be used to allow contributions from the whole donor plant to drive the cloning process.

1. A stem, low on the shrub, is arched mechanically to the ground and held in place with some small wire hoops.
2. The lower surface of the held stem is wounded (with a small notch or some grooves) and the wound is dusted with rooting hormone.
3. The wounded, dusted, section of the stem is buried in the moist soil.
4. With time, the hormone powder and contributions of IAA from the rest of the leaves on the donor plant cause roots to form from the wounded area.
5. The rooted stem can then be separated from the donor plant.

Air Layer

If a gardener is trying to propagate a tree instead of a shrub, there is no way to bring a branch down to the ground for a tip layer. If you cannot bring Mohammed to the Mountain, then you bring the Mountain to Mohammed! This is the idea of the air layer.

1. Somewhere along a young stem in the tree canopy, the lower surface of a stem is wounded and the wound dusted with rooting hormone.
2. A few hundred cubic centimeters of moist sphagnum moss or even moist soil is packed around the wound.
3. The sphagnum/soil is held in place with plastic film, and the film is secured around the stem with twist-ties above and below the wound. The soil has to be kept continually moist.
4. With time, roots develop in the small wad of sphagnum. The rooted branch can then be cut from the donor tree.

Tissue Culture

When one is trying to make many thousands of individuals of one clone, then a different method is needed. Tissue culture to the rescue!

1. First you need some donor tissue. This is called the explant. The tissue has to be at least parenchyma, but is better if it is meristematic. The tissue has to be surface-sterilized. This is done by immersing the tissue in a solution of sodium hypochlorite (laundry bleach), rinsing in sterile distilled water, then perhaps slicing off the killed surface layers.

2. The explant is placed in a sterilized liquid medium on a shaking machine. This medium contains water, minerals, vitamins, sugar (energy for growth by respiration), and dilute auxin (usually indole-butyric acid). The auxin stimulates the cells of the explant to divide rapidly to form callus. The callus is broken up by the shaking action. Thus the liquid medium becomes loaded with small callus pieces.

3. The callus pieces are now spread across a sterile solid medium. The medium contains water, minerals, vitamins, sugar, and cytokinins. The medium is solidified into a gel by adding a small amount of agar. The container is kept under light. The combination of cytokinin and light causes shoots to be initiated on each callus piece.

4. The shoots are moved onto a solid medium that contains water, minerals, and agar. Depending on the species, there may also be some auxin in the medium. The auxin from the leaves on the shoots (or in combination with auxin from the medium) cause root initiation.

5. The plants can be moved to soil and slowly eased from humid conditions to successively drier conditions. Ultimately the plants can be moved to field conditions.
Because each explant can initiate indefinitely many callus pieces, and each callus piece can make a new plant, the number of plants produced can be extremely high.

Chemical fertilisers

Choice of a fertiliser depends on unit cost of nutrient present in it and its agronomic efficiency under a given situation. Fertiliser is a valuable input and measures should be taken to reduce its losses and to increase its uptake and utilisation by the crop. Selecting a situation-specific fertilizer and choosing the time and method of application according to crop demand would minimize losses and increase its efficiency.

Nitrogenous fertilisers

Most crop plants recover only 25-35% of the nitrogen applied as fertilizers. Losses occur by ammonia volatilisation, denitrification, immobilization to organic forms, leaching and run off. Utmost care should be bestowed in selecting the type of fertiliser as well as the timing and method of application.

Choice of the nitrogen fertilizer

1. In submerged rice soil, ammoniacal and ammonia-producing fertilizers like urea are most suitable since ammonia is the most stable form of nitrogen under such conditions.

2. For acidic upland soils, ammoniacal fertilizers are most suitable during rainy season since ammonium is adsorbed on soil particles and hence leaching losses are reduced. Adsorbed ammonium is gradually released for nitrification and thus becomes available to crops for a longer period.

3. In highly acidic upland soils, urea is preferred to ammonium sulphate as the former is less acid forming.

4. In alkaline upland soils of low rainfall regions, nitrate fertilizers are preferred to ammoniacal fertilisers or urea since ammonia may be lost by volatilization under alkaline conditions

Management of nitrogenous fertilisers

1. Almost all the nitrogenous fertilizers are highly amenable to losses and since most of the crops require nitrogen during the entire growth period, split application is necessary to ensure maximum utilization by crops.

2. More number of splits may be given for long duration crops as well as perennial crops.

3. Nitrogen losses from fertilisers are more in coarse textured soils with low cation exchange capacity (CEC) than in fine textured soils. Hence more number of splits is necessary to reduce loss of fertilizer nitrogen from sandy and other light soils.

4. For medium duration rice varieties, nitrogenous fertilizers should be given in three splits, as basal, at maximum tillering and at panicle initiation stage.

5. In coarse textured sandy or loamy soils, the entire dose of nitrogenous fertilizers may be applied in 3-4 splits at different stages of growth of rice crop.

6. In areas where split application of nitrogen is not feasible due to water stagnation after planting/sowing, full dose of nitrogen as basal may be given in the form of neem coated or coal tar coated urea.

7. In double-cropped wetlands, 50% of N requirement of the first crop may be applied in the organic form.

8. As far as possible, liming should be done one or two weeks prior to the application of ammoniacal or ammonia forming fertilizer like urea since ammonia is likely to be lost by volatilization if applied along with lime

9. Almost 70% of N in urea applied by broadcast to flooded soil is lost by volatilization, immobilization and by denitrification

Measures to reduce the loss of N from applied urea

1. Urea super granules or urea briquettes may be used in places where soil is clayey and has cation exchange capacity more than 10 cmol (+) per kg of soil.

2. Sulphur or lac coated urea is suitable where soil is liable to intermittent flooding and in situations where water management is difficult. This is more suitable for direct sown crop.

3. Urea may be mixed with moist soil and kept for 24-48 hours before application to the field. Alternatively, urea may be mixed with moist soil, made into balls of about three-inch diameter and dried under shade. The balls may be placed deep into subsoil.

4. Mixing urea with five times its weight of neem cake prolongs the period of nitrogen availability to the crop.

5. For submerged soils, coating urea with coal tar and kerosene (100 kg urea is mixed with 2 kg coal tar dissolved in one litre kerosene) before mixing with neem cake is preferred to simple mixing with neem cake.

6. Coating urea with neem extract (containing about 5% neem triterpenes) at 1% rate and shade-drying for 1 to 1.5 hours before applying in direct-seeded puddled lowland rice increases nitrogen use efficiency.

7. As far as possible, urea may be applied by deep placement or plough sole placement. Deep placement of prilled urea or super granules during the last ploughing followed by flooding and planting is beneficial in light soils. Urea briquettes or super granules may be placed between four hills of transplanted rice, whereas sulphur coated or lac coated urea may be broadcast on the surface.

8. Foliar spray of 5% urea solution can be practised in situations where quick response to applied nitrogen is required. If power sprayers are used, the concentration may be increased to 15%. Fresh urea should be used to avoid toxicity due to biuret.

Phosphatic fertilizers

Fertilizer phosphorus is an expensive input and its management poses serious problems due to several complexities in its behaviour in different types of soil. This often results in its poor recovery from applied fertilizers.

Choice of phosphatic fertilizer

1. In slightly acid, neutral or mildly alkaline soils, water-soluble phosphatic fertilizers are more suitable.

2. In wetland rice soils, water-soluble phosphatic fertilizers are preferable as pH of most of the submerged soils is near neutral.

3. In strongly acidic soils whose pH does not rise above 5.5 to 6.0 even on submergence, phosphatic fertilizers containing citrate soluble form of P like basic slag, dicalcium phosphate, steamed bone meal etc. are suitable.

4. For highly acidic upland soils or submerged soils whose pH will not rise above 5.5 even on submergence, powdered rock phosphate is suitable. Soil acidity converts tricalcium phosphate in rock phosphate to plant available monocalcium form.

5. For short duration crops where quick response is required, water-soluble phosphatic fertilizers are most suitable.

6. For perennial crops like rubber, oil palm, coffee, tea, cardamom etc. phosphorus in the form of rock phosphate can be applied.

7. In black soil (Chittur taluk of Palakkad District) phosphatic fertilizers containing water-soluble phosphate like single superphosphate are most suitable.

Management of phosphatic fertilizers

1. Acid soils have to be amended with lime, dolomite or magnesium silicate and alkali soils with iron pyrite or sulphur before application of phosphatic fertilizers. This will help to reduce fixation and increase availability of P.

2. Surface application or broadcasting is preferred for shallow rooted crops whereas placement in the root zone is advantageous in deep-rooted crops.

3. Rock phosphates can be used advantageously in rice grown in acid soils during the virippu season. Powdered rock phosphate may be applied and mixed thoroughly with soil by ploughing. After two or three weeks, the field may be flooded, worked up and planted with rice. Under this situation, phosphorus in rock phosphate gets converted to iron phosphate, which on subsequent waterlogging becomes available to the rice crop.

4. Rock phosphate can be used successfully as a phosphatic source for leguminous crop since its root system can extract phosphorous from rock phosphate.

5. In single crop wetlands where rice is grown in the virippu season, application of phosphatic fertilizers can be dispensed with for the rice crop, if the second crop (usually legume or green manure) is given phosphatic fertilizers.

6. In case of rice-legume cropping sequence in acid soils, application of rock phosphate to the pulse crop helps to skip phosphatic fertilizers in the succeeding rice crop.

7. Since phosphorus requirement of seasonal crops is confined to the early stages, phosphatic fertilizers are to be applied at the time of seeding or planting. Topdressing of phosphatic fertilizer leads to wastage of the fertilizer nutrient. Further, excessive phosphates may lead to deficiency of micronutrients such as zinc, boron etc.

8. Under adverse soil conditions and where quick result is required, spraying water-soluble phosphatic fertilizers like triple superphosphate or hot water extract of superphosphate can be resorted to.

Potassium fertilizers

For most crops, potassium can be supplied as muriate of potash. But in crops like tobacco and potato, muriate of potash may cause chloride injury, reducing quality of the produce. In such cases, K may be applied as potassium sulphate.

Management of potassium fertilizer

1. In coarse textured soils and in heavy rainfall regions, potassium fertilizers should be applied in as many splits as possible, to reduce loss of potassium.

2. In fine textured soils, the entire dose of potassium fertilizers may be applied as basal.

3. In acid soils, potassium fertilizers should be applied only after lime application to prevent loss of potassium by leaching.

Average nutrient content of common fertilizers

Organic manures are waste or by products (animal/birds waste, litter, crop refuse or any other organic matter) either decomposed or treated or fresh, which enriches soil. They are bulky i.e. nutrient contents are low per unit volume. Concentrated OM contains higher % of nutrients such us oil cakes, blood/bone/fish meal important effects are:

1. improve the physical properties of the soil
2. supply all nutrients for plant growth
3. enhances soil microbial activity
4. provide a buffering action in soil reactions
5. improve nutrient holding capacity of the soil

Green manures
Green manuring refers to the practice of incorporating plant materials while they are green. It is practiced as green leaf manuring and green manuring insitu.

Average nutrient content of common Organic manures

Note: Composition of organic manures vary widely

The use of biofertilisers is quite important while practicing the concepts of integrated plant nutrient management and organic farming. Some of the commonly used biofertilisers in Kerala are as follows.

1. Rhizobium (Bradyrhizobium and Azorhizobium)
It induces better root nodulation and stem nodulation (Azorhizobium) in inoculated plants and thereby brings down the requirement of nitrogen fertilizer for the cultivation of pulses, oil seeds and legume green manures. Commercially it is available as carrier based inoculums. Method of application is seed treatment.

2. Azotobacter
Suitable only for upland crops like vegetables, tapioca, plantation and orchard crops. It is available as carrier-based inoculum. It fixes N about 15-20 kg/ha under ideal upland conditions and thereby reduces the requirement of nitrogen fertilizers by 10-20 per cent. Methods of application are seed treatment, seedling dip and direct soil application.

3. Azospirillum
It is suitable for both upland and wetland conditions and is available as carrier-based inoculum. It fixes N about 20-25 kg per ha under ideal conditions thereby effecting a reduction of 25 per cent in the quantity of N fertilizers required. Treatment with Azospirillum also induces better root formation in inoculated plants. Hence this biofertilizer is also recommended for root induction in polybag-raised seedlings of plantation and orchard crops and also for vegetable crops. The isolates of Azospirillum brasilense strains AZR 15 and AZR 37 from Kuttanad soils are highly effective for rice, vegetables and nursery plants. The strains AZ 1 and AZ 2 are effective in vegetable and nursery plants.

Method of application

Seed treatment: For treating 5-10 kg seeds, 500 g culture is required. Moisten the seeds by sprinkling water or rice-gruel water. Take 500 g culture in a plastic tray/basin, add moistened seeds, mix well and dry in shade for 30 minutes. This may be sown immediately.

Seedling root dip (for transplanted crops): Slurry of the culture is prepared by mixing 500 g culture with 50 ml of water and the roots are dipped in the slurry for 15-20 minutes before transplanting.

Soil application: Mix the culture with FYM or compost in the ratio 1:25 and apply directly in the soil.

Inoculation for paddy
Mix 2 kg of culture in 60 litres of water and soak the seeds required for 1 ha (60 kg) for 24 hours before sowing. At the time of transplanting, dip the roots of seedlings for 15-20 minutes in the culture slurry prepared by mixing 2 kg inoculum with 40 litres of water. This slurry can be used for treating seedlings required for 1 ha. Another 2 kg culture may be applied to the field along with FYM or compost.

4. Blue green algae(BGA)
Mainly recommended for wetland rice cultivation. However, the use of this biofertilizer is not feasible in acidic soils with pH below 6.0. It is available as carrier-based inoculum and it fixes N about 25-30 kg/ha under ideal conditions.

Method of application: Direct broadcasting in the rice fields @ 10 kg/ha one week after transplanting the seedlings.

5. Azolla
It is suitable for wetland rice cultivation. The required quantity of azolla will have to be raised in the farmers' field itself. Fixes N about 25 to 30 kg / ha.

Method of application: Apply fresh azolla @ 10 t/ha before transplanting the rice seedlings at the time of ploughing.

6. Phosphate solubilising bacteria and fungi
Recommended mainly for upland crops raised in neutral and slightly alkaline soils. Available as carrier-based inoculum. Enables the efficient utilization of cheaper sources of phosphatic fertilizers such as rock phosphate by crop plants in neutral and alkaline soils.
Method of application: Seed treatment and direct application.

7. Vesicular / arbuscular mycorrhiza (VAM/ AM)
Vesicular arbuscular mycorrhiza is mostly recommended for upland especially for raising container and tissue culture plantlets and transplanted crops. It mainly improves the uptake of available P by inoculated plants. There is also an enhanced absorption of water and other nutrients such as N and K and certain micronutrients. Mycorrhiza inoculation can improve the survival and establishment of tissue culture plantlets under field conditions. Also induces better resistance against certain soil borne plant pathogens. It is commercially available as granular inoculum consisting of infected roots and soil with mycorrhizal spores. It is given as soil application.

VAM fungus Glomus microcarpum var. microcarpum is suitable for tropical tuber crops. The inoculation can be done by placing inoculum (3-5 g/sett) beneath the sett before planting. The rate of spore load in the inoculum should be to the tune of 50 to 400 spores per 100 g soil medium. Method of application is the rooted infected cutting technique.

Application techniques of biofertilisers

1. Seed treatment
Five hundred grams of commercially available inoculum will be required for treatment of seeds for one-hectare area. For this, thick slurry of the carrier-based inoculum is initially prepared by mixing 500 g of the inoculum in 1.25 litre of water. The stickiness of the biofertilizer on seed surface can be significantly improved by using 10% jagerry solution or 5% sugar solution supplemented with 40% boiled and cooled gum arabic solution or rice-gruel water. The required quantity of seed material is then gently mixed with this slurry by taking care not to damage the seed coat. The treated seeds are spread evenly over a gunny bag and dried in shade and sown immediately in moist soil. Under no circumstances, the treated seeds are exposed to direct sunlight for a longer period of time since the UV rays of solar radiation will reduce significantly the population of inoculated bacteria on seed surface.

2. Seedling treatment
This method of application is mainly recommended for transplanted crops. In this procedure, the roots of seedlings to be transplanted are dipped in loose water slurry of the biofertilizer (500 g in 2.5 litre of water) for 20 minutes, prior to transplanting.

3. Soil application
Soil application is generally recommended for all types of biofertilisers except Rhizobium, Bradyrhizobium and Azorhizobium. The method is to apply the biofertilizer after mixing with dried FYM, compost or vermicompost @ 1:25. For crops of six-month duration, the recommended dose is 1-2 kg/ha. This can be increased to 2-4 kg/ha for crops of more than six-month duration. For perennial crops, 10 to 25 g of the biofertilizer is to be applied in the root zone during the first year and 25 to 50 g during subsequent years. This can be done at the time of sowing, transplanting or during intercultivation.

Factors influencing the efficient use of bio-fertilisers in Kerala

1. Use adequate quantity of organic manure (as per