Phosphorus pools under integrated phosphorus management of upland direct-seeded rice (Oryza sativa) in North-Eastern Hill region of India

A field experiment was carried out during the rainy (kharif) season of 2019 at Umiam, Meghalaya, to determine the phosphorus pools in acid soils of upland direct-seeded rice (Oryza sativa L.) in North-Eastern Hills region under varying phosphorus-management practices. Eight treatments with combinations of different nutrient sources, both organic and inorganic were taken replicated thrice in a randomized block design. The treatments involving chemical fertilizers resulted in higher levels of inorganic P (232 mg/kg) owing to an increase in Fe-P, Al-P and Ca-P pools. On the other hand, treatments utilizing organic sources of nutrients like farmyard manure (FYM), vermicompost and poultry manure showed higher levels of organic-P (168 mg/kg) in soil. Application of integrated organic nutrient sources as in 25% farmyard manure + 25% vermicompost + 25% poultry manure + phosphorus-solubilizing bacteria resulted in significantly higher available-P (5.5 mg/kg) and organic-P pool (168.2 mg/kg) over the other treatments. But the total P was significantly higher with 100% recommended fertilizer dose (391.5 mg/kg) which showed an increase of 10% over the control.