|Class 8 Biology Microorganisms: Friend and Foe||Microbes as Biofertilizers|
Microbes as Biofertilizers
Fertilizers are substances added to enhance the soil fertility. This results in higher yields & healthier plants. Chemical fertilizers, however have several disadvantages like they are toxic to various life forms, can cause imbalance in soil ph, results in soil infertility, degrades ecosystem, plants become susceptible to many diseases, fruits & vegetables have high toxic residues. Excessive use of fertilizers can cause environmental pollution.
Use of biofertilizers is preferred as they do not include any of the disadvantages mentioned above. Biofertilizers are living organisms that enrich the soil nutrient quality. Some of the sources of biofertilizers are bacteria, fungi, cyanobacteria etc.
Rhizobium, is an example of a nitrogen fixing bacteria present in the root nodules of leguminous plants. Nitrogen is a macronutrient for the growth & development of plants. Rhizobium enriches soil with nitrogen.
Mycorrhiza, a symbiotic association between fungi & certain plants, also enhance the phosphorus content which in turn helps in better growth & development of plants. They are resistant to pathogens.