The difficulty with phsophatic fertilizer is, when it is applied to black soils (Vertisols) a large fraction of it is fixed (80-85%) in the soil and only small portion (15-20%) is available to the plants. The fixed or unavailable forms are solubilized and mineralised by PSB by producing organic acids and phytase enzyme, which is than available to crops. It also increases the utilization efficiency of super phosphate. The FYM also improves phosphorus availability due to production of organic acids such as citrate, oxalate, lactate etc. during decomposition, which hold AI and Fe. Thus, P...