The biofertiliser option

India, a country once importing nearly half of its foodgrain requirement, had taken enough pains to become self-sustainable and an exporter of foodgrain. The Green revolution of 1966-67 in India was led by the input-responsive crop varieties which increased total foodgrain production from 72.35 million tonnes in 1965-66 to 241.6 million tonnes in 2011-12.

Chemical fertilisers have played a significant role in increasing this production in India. Now India is second only to China in fertiliser consumption with 26.5 million tonnes in 2009-10, which is projected to reach 41.6 million tonnes in 2020.

However, Indian farmers are stuck with multi-pronged problems with respect to chemical fertiliser. The first of them is the enormous increases in the prices of DAP and MOP fertiliser. The retail price of MOP rose to Rs 23,100/tonne in the current kharif season in 2012-13 from Rs 12,040/tonne in the 2011-12 rabi season. Similarly, DAP prices rose to Rs 26,500/tonne from Rs 20,000 per tonne in the same period.

Secondly, with no other option available, the overuse of urea increased. Thirdly, due to the non-judicious use of chemical fertilisers, land degradation, soil infertility and deficiency of soil micro nutrients has increased in several parts of the country. Fourthly, the status of alternative fertiliser inputs, which are organic in nature, is not satisfactory. The quality of the product is a major concern.

NUTRIENT MANAGEMENTSole dependence upon chemical fertilisers will only aggravate the situation in the coming future. Therefore, integrated nutrient management (INM) has gained importance from the sustainability point of view.

Under integrated nutrient management, the ultimate aim is to integrate or combine all natural and man-made resources, so that crop productivity increases at an environmentally friendly rate and soil productivity is not sacrificed for the future generations. Under the concept of INM, mycorrhiza is an indispensable agricultural input.

Mycorrhiza basically is the name given to the system in which fungal micro organism make an association with the roots of plants. This mutual association results in the improved supply of water and nutrients, such as phosphate and nitrogen, to the host plant. In return, the fungal partner gets plant-fixed carbon as its food. We can envisage mycorrhiza as the extended arms of plants which procure foods from more distant regions under the earth where the roots of plants cannot reach. The best part of this story is that this association is natural and nearly 90 per cent of plants make such associations.

This broad spectrum host-non-specificity of mycorrhiza is an important factor in its use as biofertiliser when compared with other microbial biofertilisers such as rhizobium which are host-specific. Also, the shelf life of mycorrhiza biofertiliser (3-5 years) is much higher than rhizobium (six months).

The use of mycorrhiza biofertiliser provides benefits at both ends of crop management, with reduction in chemical fertiliser (up to 50 per cent in certain cases) and associated yield increase (5-25 per cent).

The role of mycorrhiza in supplying nutrients is particularly important from the phosphorus nutrition point of view, which is otherwise an extremely immobile element in soil.

With the rising price of phosphatic fertilisers and nearly 50 per cent of Indian soils being phosphorus deficient, mycorrhiza can play a big role in farm fertilisation. Apart from this, mycorrhiza also performs other functions, such as increasing tolerance to environmental stress, providing protection from soil-born pathogenic disease and maintaining biological health of the soil.

RIGHT MIXUltimately, we have to realise that soil is a living system like us which drinks, respires, moves from one place to another and gets weathered over time. Such a delicate system, which is the base for holding crops and other plants, needs utmost care in the ways in which it is treated. India is yet to see the growth of organic agricultural inputs in conjugation with chemical sources, compared with the Western countries. Mycorrhiza biofertiliser can be a reliable partner with chemical fertilisers.

Tags: exporter of foodgrain, Green revolution, agriculture and fertiliser, biofertiliser