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Organic Cotton Production
- To produce one tonne of cotton (kapas), usual requirement for major plant nutrients are 60 : 30 : 15 kg NPK per hectare. The plant nutritional requirements are to be met either by application of synthetic chemical fertilizers or by application of organic manures and naturally available minerals. It is possible to grow cotton organically by adoption of integrated nutrient management, the technique of which is as under.
- Crop rotation, green manuring, particularly with legumes enriches the soil not only in nitrogen content but also provides base material for increase in biological activities to harness atmospheric nitrogen and to mobilise mineral as a source for nutrition.
- In such enriched soil, application of organic manure further enhances biological activities which helps in release of nutrients to the crop in balanced manner. Organic manure quality and nutritional status can be further increased by addition of 25-30 kg of rock phosphate powder (100 mesh) while filling the compost pit. After partial decomposition of biomass, by which time temperature of the compost pit comes down to 30’ to 350C. Addition of 100 g of Azotobacter and 250 g PSB /PSM per tonne of biomass is recommended. Such phosphocompost inoculated with biofertilizers contains around 1 per cent nitrogen, 0.8 per cent P2O5 and 1 per cent Potash, plus micronutrients. Application of 1 tonne of compost can make available nutrients sufficient to produce 2 tonnes of cotton.
- To further enhance availability of nitrogen, intercropping of legume viz., groundnut, moong/urd bean, pigeonpea, soybean can contribute some left over nitrogen to the companion cotton crop. Planting of maize as an intercrop too is advantageous as it provides perching place for birds and shelter for predators which keep cotton pests under check. Maize crop root system in association with mycorrhiza solubilizes phosphorus/minerals for the use of maize as well as companion crop cotton.
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Bio-Fertilizers
- Continuous use of chemical fertilizers has resulted in soil degradation, multiple nutrient deficiencies and air and water pollution. To sustain soil health and high crop productivity, judicious use of different sources of nutrients such as chemical, organic and biofertilizers is essential. In this context biofertilizers assume importance as a component of integrated nutrient management system. Biofertilizers are cheap and ecofriendly and can supplement other sources of nutrients to an extent of 25-30 per cent.
Azospirillum
- Azospirullum, a microaerophyillic bacterium, is known to enter into associative symbiosis with xylem vessels of plant roots. Besides its ability to fix elemental nitrogen. Azospirillum is also known to secrete growth promoting substances like GA and IAA, which enhance root proliferation and growth of crop plants. They are known to fix 25-40 kg N/ha/year.
- Azospirillum was introduced for both seed treatment (20 kg/ac) and soil application (2 kg/ac).
Phosphobacteria
- Phosphobacteria, particularly those belonging to genera Bacillus and Pseudomonas, possess the ability to solubilise insoluble inorganic phosphorus and make it available to plants. It has been estimated that about 30 kg P/ha/yr is solubilized by their application.
- Phosphobacteria can be used for soil application @ 2 kg/ha along with Azospirillum (2 kg/ha) and 100 kg FYM.
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Biocontrol based pest management
- Release of Chrysoperla sp @ 550/ha 20-25 DAS and again at 35 DAS.
- Release of Trichogramma chilonis @ 5 cards ha-1 at 45 DAS
- Spray of H-NPV @ 250 larval equivalent/ha (2 x 108 PIBS/larval equivalent) for young boll worms of Helicoverpa armigera.
- Detopping after 80 days of growth.
- Alternative spray with b.t. formulation @ 1.5 lt/ha.
- Application of neem-based formulations-neem oil @ 1 lt/ha and 1 per cent neem seed-kernel extract.
- Release of Bracon hebator to kill bollworm larval
- Bird perches @ 4/ha.
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Organic soil amendments
- FYM @ 5 t ha-1
- Insitu green manure with fodder cowpea incorporated between cotton rows at 40 DAS.
- Spreading loppings from Sesbania spp. obtained from 2-m dense rows after 10 cotton rows, in the entire field.
- Vermicompost @ 1-2 t ha-1
- Seed inoculation of Azotobacter @ 500 g commercial product or seed required per ha.
- Utilization of Trichoderma viride for composting farm-waste including cotton stalks.
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Pest and disease management
- For organic cotton production, selection of varieties/hybrids tolerant at least to sucking pests and disease like black arm, is essential. Such cottons respond to integrated pest and diseases management.
- Treatment of seed with Trichoderma and their application by mixing in organic manure suppresses pathogenic organisms found around cotton roots as a result of which incidence of plant wilt/mortality is minimised.
- The major problem in cotton production is bollworms, viz., Heliothis, spotted and pink bollworms. These can be checked by the balanced growth of the plants on provision of nutrition from organic system.
- Survey and surveillance of pest is another major component in crop production. Incidence of pest can be assessed by putting pheromone traps for heliothis/spotted/pink bollowrms. Light traps also give fairly good assessment for the incidence of bollworms. On observance of incidence of these pests use of bioagents like Bacillus thuringiensis, NPV, Trichogramma are recommended. Biopesticides like neem and garlic extracts, garlic and green chillies are recommended to protect the crop from lepidopteran insects.
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Organic cotton production technology
- Today, organic cotton encompasses, a range of farming systems including those known as biological, low-input, organic, regenerative, green, eco-friendly or sustainable. Basically, the practices and principles in these alternate systems involve crop rotation, integrated pes t management (IPM) conservation tillage, crop diversification, genetic improveme nt disease/pest prevention and soil health amelioration. Sound organic cotton produc tion packages are developed based on the following principles:
- Promotion of natural processes – nutrient cycling, atmospheric N fix ation, cotton-plant-pest-natural enemy interactions and integration of these complementary processes into the production system.
- Avoiding the use of those off-farm inputs which are a potential threat to the soil and aquatic environment, as well as health of the farmers, farm animals and consumers.
- Allowing the biological/genetic potential of the variety/hybrid to be expressed fully with minimum interventions.
- Improved farm management to conserve soil, water energy, biological diversity and on-farm agro-wastes.
- A fertile soil is a pre-requisite for organic cotton production. The soils native organic C content should be improved and stabilized at such a level that the anticipated production levels do not cause a decline in soil organic C. Crop rotation with legumes, cover cropping, green manuring, compost, bio-mulches biofertilizers are generally employed to improve fertility status. Soil amendments are naturally mined permitted chemicals can be employed to supplement native fertility.
- Weed management is primarily achieved through preventive techniques (selection of perennial weed-free field, clean seeds, completely decomposed compost/FYM, crop rotation, cover cropping, mulching, smother crop, etc.). Cultural, mechanical and manual methods can be employed to supplement preventive measures.
- Pest management is achieved through the selection of pest tolerant varieties, conservation of natural enemies and inundative releases of predators/parasites/pathogens and supplemented with botanicals.
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Soil and water management
- The response from organic sources of nutrients get enhanced on adoption of soil and water management practices. Irrigation either by drip system or application of water in furrows does not disturb micro climate around the plant. Such technique is useful in minimizing humidity around the plant vis-à-vis incidence of pest and diseases.
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Coloured Cotton
- The naturally coloured cottons are environment friendly as they need no dyeing and economically viable as they are sold at premium price. They do not fade on washing.
- The greatest disadvantage of coloured cottons at this stage is that they yield less and fibres are shorter with low strength, low micronaire value and low maturity coefficient. Efforts are being made to improve the yield and quality of naturally coloured cotton which can be machine spun.
- Due to out crossing the coloured cotton will not maintain the intensity the intensity of colours over generations.
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