Biofertilizers- An Introduction

This is a continuing series of articles on Biofertilizers. This is part 1 of the series.

Soil fertility depends on several factors chiefly being chemical, physical and biological. While physical and chemical factors have been the subject of countless research studies, biological factors have not received enough attention. Soil respiration, nitrogen and mineralisation etc. are important factors that play an important role in determining the biological health of soil.

The indiscriminate use of chemical fertilizers especially in developing countries which no doubt has increased yield but has also had adverse effects. Organic fertilizers are thus a safer option and are not only economical but also safe and renewable source. Soil erosion, indiscriminate use of pesticides, insecticides and chemicals, mining, road construction, power plants, landslides, deforestation lead to decrease in soil health which can be restored by soil conversation methods such as afforestation, biomining, use of biofertilizers and bio pesticides and encouraging biodegradable products.

What is a Biofertilizer?

Organisms which help in increasing the nutrient availability to plants as a result of their biological activities. They help in bringing about soil enrichment. They can fix atmospheric nitrogen either freely or in the form of various symbiotic associations with plants. Thus Biofertlizers are associations of living organisms with plants. It can be any substance that contains such living organisms that is beneficial to plant growth.

History of Biofertilizers-

• 1895, first time, Noble and Hiltmen introduced a legume inoculant- “Nitragin”
• Replaced later by peat base.
• 1960, Yellow seeded soyabean.
• Rhizobial Biofertlizers.
• In India, in 1960’s on a commercial scale. During the 6^th five year plan, the Indian govt. sanctioned a project on Development & Use of Biofertlizers at six regional centres in Ghaziabad, Hissar, Jabalpur, Pune, Bangalore and Bhubaneshwar.

Classification of Biofertilzers-

Bacterial Biofertilzers-

1. Biological Nitrogen fixing (Symbiotic)
2. Non symbiotic, free living Nitrogen fixers

Cyano-bacteria (BGA, Blue Green Algae)-

1. Symbiotic
2. Free living

Fungi as Biofertilizers-

1. Ectomycorrhizal Fungi
2. Endomycorrhizal Fungi
3. VAM (Vescicular Arbuscular Mycorrhiza)

Advantages of using Biofertilizers-

1. Reduction in use of chemical fertilizers
2. Secrete plant growth hormones which help in plant growth
3. Protect the plant against attack by pathogens
4. Improve fertility of soil
5. Can be produced easily on a large scale
6. No special care is necessary while using biofertilizers
7. Farmers may grow (for example Azolla) in their own fields

Read part 2

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