Sustainable Agriculture Using Biofertilizers
Organic Farming With The Help Of Bioinoculants
Jun 5, 2009
Biofertilizers or bioinoculants are ready to use, live formulates of beneficial microorganisms, which when applied to soil, roots or seeds, enhance the availability of different nutrients to the plant by their inherent metabolic activities. Land under agriculture is not increasing with the rate to keep up with the pace of the demand for food across the world. And with the advent of green revolution technologies, there has been an ever-increasing dependence need of synthetic fertilizers.
Are Synthetic Fertilizers So Bad?
Synthetic fertilizers are usually a combination of compounds of nitrogen, phosphorus and potassium, the popular N-P-K fertilizers. For example, a bag of synthetic fertilizer having the numbers 15-5-10 printed on it means that it contains 15% nitrogen, 5% phophorus and 10% potassium. And the rest is called “filler” or “carrier” which could be sawdust, sand, dirt or even toxic industrial waste! Continuous addition of synthetic fertilizers creates an unbalanced nutrient state in the soil.
According to Howard Garrett, high levels of nitrogen and low levels of trace minerals force fast growth that results in very weak watery cell growth in plants. Plants appear to grow and flower normally and hence people think that everything is fine. But the imbalance and the watery cells bring on insects and diseases. The source of phosphorus used in synthetic fertilizers (triple super phosphate) locks onto magnesium, manganese and all sorts of other trace minerals. It ties up these nutrients making them unavailable to plants. Also the source of potassium, which is generally potassium chloride is bad for many types of plants and is also harsh on the soil.
Furthermore, since these fertilizers are highly soluble, they can easily run off during rains or heavy irrigation and enter water bodies like rivers, lakes or streams. In these fragile water ecosystems, they disturb the delicate nutrient balance by adding limiting nutrients like phosphorus and can lead to a phenomenon called “eutrophication.” This results in overgrowth of algae and other water plants thereby suffocating the entire water body and consequently leading to the destruction of the entire ecosystem.
Are Biofertilizers Beneficial?
Absolutely yes! According to ICRISAT data, on an average, biofertilizers increase crop yield by 20 – 30%. They also replace nitrogen and phosphorus by 25%. They stimulate plant growth, activate the soil biologically and restore natural soil fertility. They are cost effective, environment friendly and their benefit to cost ratio is fairly high.
What Are Biofertilizers Made Of?
Biofertilizers consist of microorganisms (bacteria and fungi) which fix atmospheric nitrogen (convert inorganic dinitrogen into nitrates, a form easily utilisable by plants), solubilise phosphorus (from an insoluble form, rock salt, to a soluble and utilisable form) and promote uptake of immobile ions of zinc and other micronutrients (mycorhizae- VAM). These include bacteria like Azolla, Azospirillum, Azotobacter, Rhizobium, cyanobacteria (blu-green algae), phosphobacteria, Sesbania, etc. Biofertizers also provide growth promoting substances like vitamins, hormones, amino acids etc. to the plants.
Although biofertilizers are absolutely harmless, there are certain Dos and Don’ts associated with their use. For example, they should not be mixed with chemical fertilizers or insecticides or herbicides. These and other precautions need to be followed for ensuring efficacy of biofertilizers. Biofertilizers should be used as a major part of an Integrated Agricultural System where there is reliance on all things “organic.” They seem to be the answer for the world’s food and environment problems.
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