What are Biofertilzers and what are used for



Biofertilizer is the biologically active products or microbial inoculants of bacteria, algae and fungi, which may help biological nitrogen fixation for the benefit of plants. Biofertilzers also include organic fertilizers (manures, etc.), which are rendered in an available form due to the interaction of micro­organisms or due to the interaction of micro-organisms or due to their association with plants. Biofertilizers thus include (i) symbiotic nitrogen fixers e.g. Rhizobium spp.; (ii) asymbiotic free nitrogen fixer e.g.

Azotobacter, Azofpirillum, etc. (iii) algae biofertilisers e.g. blue green algae or BGA in association with Azolla; (iv) phosphate solubilising bacteria; (v) mycorrhizae; (vi) organic fertilizers.

The need for the use of biofertilzers has arisen, primarily of two reasons. First, because increase in the use of fertilizers leads to increased usage of chemical fertiliizer leads to damage in soil texture and raises other environmental problems.

Therefore, the use of biofertilzers is both economical and environments friendly. The pragmatic approach will be to develop the integrated nutrient supply system involving a combination of the use of chemical fertilizers and biofertilizers.

Rhizobia are able to enter into symbiotic relationship with legumes (pulses, etc.). They fix atmospheric nitrogen and thus not only increase the production of the inoculated crops, but also leave a fair amount of nitrogen in the soil, which benefits the subsequent crop. Following seven groups of Rhizobia have been recognised for inoculating legumes in India: R. leguminosarum, R. japonicum and Rhizobium spp.

The new technology for industrial preparation for rhizobial cultures included the following: (i) seed pelleting with gum arabic or carboxy methyl cellulose as percolated seed (ii) polyacrylamide entrapped rhizobia; (iii) frezedried or lyophilzed culture of rhizobia; (iv) Rhizobium paste; (v) inoculants in liquid/frozen concentrate form; (vi) granular soil inoculants to be applied by aerial application; (vii) natural peat granule as soil implant inoculum.