NEET Biology Food Resources Crop Production System Chapter Notes

Carbon needed by plants is obtained from CO₂ of the air, hydrogen and oxygen from water. The rest are all taken from the soil. Iron, manganese, copper, zinc, boron, molybdenum and chlorine and micronutrients, required by the plants only in trace quantities while all the others are taken in large quantities and hence, called macronutrients. Thus a plant lives in an environment of air and water, with the soil serving as the source of water and mineral nutrients.

 

Increased crop production is necessary to meet the demanding food requirement of our population. Crop production involves the exploitation of plant responses within the soil and environment to produce a high yield per unit area of land.

 

Any soil continuously under cultivation needs to be augmented and restored. It is in this context that the system of farming, soil management and manuring practices etc., influence the productivity of soils.

 

Indian soils are very poor in organic matter as well as in nitrogen. Materials employed for maintaining or improving soil fertility may be classified as manures, fertilizers, biofertilizers and organic fertilizer.

 

These are the bulk materials such as animal manure of green manures. Their addition to the soil improves its physical condition, replenishes and keeps up its humus status, maintains the optimum conditions for the activities of soil microorganisms.

Manures such as farmyard manure and compost enrich the soil with different kinds of nutrients, hence manures are needed in large quantities. Manures also improve the water holding capacity of the sandy soil and aeration and drainage in clayey soil as they add organic matter to the soil. The organic content of the manure form food for micro-organisms and the micro-organisms are helpful in releasing the nutrients by their degrading activity.

 

Manures include farmyard manure (FYM), compost, green manure, vermicompost etc. Farmyard Manure: Good-quality farmyard manure is perhaps the most valuable organic matter applied to a soil. It consists of a mixture of cattle during, the bedding used in the stable and of any remnants of straw and plant stalks fed to cattle. The cattle dung, together with stable waste and house sweepings, are first collected and deposited in a pit which is compacted. The compacting should be sectional. When each section is filled with the wastes, it should be plastered with a mixture of mud and dung in equal proportions. Before plastering, four of five buckets of water should be added to the manure in the pit. Plastering conserves moisture and nitrogen and also prevents the housefly menace. The manure becomes ready for use in about four to five months after plastering. Farmyard manure must have moisture for its roper rotting. Dried farmyard manure loses quite a lot of its nitrogen and ammonia content. Farmyard manure should ideally be used with superphosphate, as the manure is generally deficient in phosphates. A well decomposed FYM has 0.5% N, 0.2% P₂O₅ and 0.5% and 0.5% K₂O.

 

Table showing the areas where different types of plants are used as green manure.

 

For the proper rotting of the green manure, it is necessary that the green material should be succulent and there should be adequate moisture in the soil.Plants at the flowering stage, contain the greatest bulk of succulent organic mater

with a low carbon/ nitrogen ratio. The incorporation of the green manure crop into the soil at this stage allows a quick liberation of nitrogen in the available form.The increase of yield after green manuring is usually of the order 30 to 50 percent.

 

Vermicomposting: vermicomposting is the process of using worms and microorganism to turn kitchen wastes into black, earthy smelling nutrient rich humus.The worms used in vermicomposting are called red worms (EISENIA FOETIDA) which is also known as red wrigglers or manure worms.

 

The materials to be degraded (kitchen wastes in general) are taken in a container/bin/woodbin whose bottom can be moved. The base of the container is liner with small stones or boards to keep away other worm-loving creatures from entering into the bin. The bin is lined with a bedding, which may be composed of shredded newspaper, corrugated cardboard or peat mos. The type of bedding used,must be able to absorb maximum quantity of water and retain both moisture and air. The kitchen wastes are introduced into the bind which consists of all vegetable and fruit wastes, coffee grounds and tea bags. As the vermicomposting worms are not tolerant to garlic and onion skin, addition of these is avoided. The worms are introduced into the bin and the temperature is maintained between 55 and 77°F. The worms have gizzard like structure hence fine gritty material like cornmeal, coffee ground or finely crushed egg shells are added. Addition of fat rich material, meat scraps or bones, quicker composting process, plastic bags, rubber bands, sponge, aluminium foil and glass pieces should be avoided.

 

At the given right environment, the worms digest the kitchen scraps and bedding faster than any other compost method. The material passes through the worms body ad become ‘castings’. In 3 or 4 month the worms digest nearly all the garbage and bedding and the bin will be filled with a rich black natural fertilizer and soil amendment. Compared to ordinary soil, the worm castings contain 5 times more nitrogen, 7 times more phosphorous and 11 times more potassium. They are also rich in scale depending on the structure o the soil. Vermicomposting can be done by availability of wastes available at a given time on a large scale, the same process is done b adding the material to be decomposed into a deep pit in the comer of th field or garden.