Imtilemla SMS
(Soil Conservation) Krishi Vigyan Kendra, Tuensang
Soil is the single most important natural medium for crop production. Crops require different nutrients for their growth and development which they derive from the soil. Thus, soil fertility is an important requirement for crop production.
In fact, soil supplies 13 of the 16 elements required for the nutrition of crop plants. These essential nutrients must be available continuously in balanced proportions. But this is not always true with all types of soils. There are certain soils which do not fulfill these objectives and, as such, are supposed to be infertile. On the other hand, there are soils which fulfill all these requirements and are called fertile soils. Therefore, soil fertility is an aspect of the soil-plant relationship viz. plant growth with reference to plant nutrients available in soil.
Soil fertility is the most important asset of a nation. Maintenance of soil fertility is an important aspect of agriculture. Nutrients are continuously removed from the soil by crops in addition to losses by leaching and erosion. It is therefore, imperative that sound soil and crop management practices are adopted to improve and maintain soil fertility and soil physical conditions for the purpose of sustained crop production. It is now a well established fact that long term application of organic manures and chemical fertilizers helps to improve and maintain soil fertility, soil productivity and soil physical conditions. Maintaining soil fertility is imperative to step up agricultural production to meet the demands of the ever increasing population.
Soil fertility and agricultural production can be maintained only by efficient and judicious management of nutrient addition to the soil from external sources. Of the two sources most widely used all over the world, one is organic in nature the organic manures, simply called manures, and the other comprises the synthetic or naturally occurring chemical fertilizers, simply called fertilizers.
What are manures & fertilizers?
Manures maybe defined as materials which are organic in origin, bulky and concentrated in nature and capable of supplying plant nutrients and improving soil physical environment having no definite chemical composition with low analytical value produced from animal, plant and organic wastes and by products. It includes farm yard manure (FYM), composts, green manures, etc. Generally farm yard manures and composts are the decomposed products of agricultural by-products (animals and crops). Whereas green manures may be defined as materials which are undecomposed green plant tissues susceptible to decomposition in the soil after incorporation.
Fertilizers may be defined as materials having definite chemical composition with a higher analytical value and capable of supplying plant nutrients in available forms. Usually fertilizers are inorganic in nature and most of them are the products of different industries. There are generally three types of chemical fertilizers available in the market namely Nitrogenous, Phosphatic and Potassic fertilizers. These types of fertilizers are mostly used by the Indian farmers for crop cultivation. The most important nitrogenous, phosphatic and potassic fertilizers used by the farmers are ammonium sulphate, urea as N sources, superphosphate and rock phosphate as P sources and muriate of potash as K sources. Sometimes micronutrient fertilizers like zinc sulphate as zinc sources, borax as boron sources, etc is used by farmers.
Efficient use of fertilizers
Researchers have shown that plants cannot utilize more than 60% of Nitrogen and 20% of Phosphorus applied through fertilizers, even under the best management practices. Under ordinary conditions plants hardly avail more than 30% Nitrogen and 10% Phosphorus applied through fertilizers. Major part of the nitrogenous fertilizer is either lost to the atmosphere in the form of gas or leached down in the soil along with soil water. Likewise a large portion of phosphorus is fixed with the soil particles and plants cannot avail it. Therefore, the following measures should be considered in order to obtain maximum benefit with the minimum dose of fertilizer applied.
1. Fertilizer scheduling should be based upon soil test and crop need
2. Placement of fertilizers: Placement of fertilizers is preferred to the broadcast application. This is especially important for phosphatic and potassic fertilizers. Placement of fertilizers in the root zone (5-8 cm deep) increases availability of nutrients to the crop.
3. Mixing should be done carefully
4. Soil texture and duration of crop
5. Water management 6. Use of micronutrients
7. Use of amendments
8. Proper agronomic practices
9. Use of organic manures: Application of fertilizers coupled with organic manures has mutual beneficial effect on each other. Organic manure prevents the loss of fertilizer nutrient from the soil and also counteract the acidic or alkaline impact of fertilizers. On the other hand, in the presence of fertilizer nutrients, organic manures release plant nutrients more rapidly.
10. Use of bio-fertilizers
11. Use of slow release fertilizers
12. Use of coated urea
Conclusion
Although soil is a rich reservoir of plant nutrients, continuous and intensive cropping and improper management can lead to rapid depletion of these nutrients within the course of a few seasons. Crop harvest causes a big drain on nutrients of the soil. In order to maintain an optimum level of yield from the soil, we have to supply nutrients from outside to the soil through fertilizers. This being the situation, it is important to educate farmers on the judicious use of this input so that all the harmful effects may be prevented and optimum yield may be obtained.
.JPG)
