Biofertilizers

Consisting of N-fixing bacteria such as Azospirillum sp. and Azotobacter sp. Azospirillum sp. are more effective in clay soils with adequate nitrogen while Azotobacter sp. in sandy loam soils.

Micro-organisms like Pseudomonas strieta, Bacillum polymyxa, Aspergillus awamori, Bacillus magaterium, etc. have the ability to solubilize the insoluble form of phosphate to soluble form. Application of phosphate solubilizing cultures increased the phosphate uptake and saved super phosphate equivalent to 30-35 kg P₂O₅/ha).

In addition to these, many cellulolytic fungi have the ability to decompose recalcitrant crop residues, which builds up soil organic matter besides N-addition. With the intensive cultivation, deficiency of micronutrients viz., Zn, Mn, Fe and Cu is increasing at alarming rate. Iron chlorosis can be corrected by soil application of 25-50 kg/ha FeSO₄ or by foliar spray of 2% FeSO₄.