Influence of Organics on Phosphorus Fractions under Sweet Corn in Coastal Region of Guntur District, Andhra Pradesh

Abstract

A field experiment was conducted during Kharif, 2013 at Agricultural College Farm, Bapatla, Guntur district to study the influence of farm yard manure (FYM) and poultry manure (PM) alone and in combination with fertilizers on different P fractions viz., saloid-P, Al-P, Fe-P, Ca-P and total P in soil at different stages of sweet corn. Among various P fractions saloid-P was significantly influenced by application of organics over sole fertilizer treatment at all stages. The treatment supplied with 50 % of N through PM and 50% through inorganics registered 71% increase in saloid -P over 100% N through fertilizers at knee-high stage, while the per cent increase was only 20 % at harvest. The remaining P fractions viz., Fe-P, Al-P, Ca-P and total-P were not markedly influenced by the application of organics at any stage of crop growth. Al –P ranged from 25.67 to 32.40, 27.97 to 42.73 and 31.00 to 42.83 mg kg^-1 at knee high, tasseling and harvest stages, respectively. Highest Fe-P was recorded in treatment with 100 % N through PM at all stages whereas, the lowest Fe-P was observed in no nitrogen treatment. Maximum Ca-P values of 171 and 207 mg kg^-1 at knee high and tasseling stages, respectively were registered in the treatment supplied with 100% N through PM while, 185 mg kg^-1 was observed at harvest in the 50% N-PM+50% N- Fertilizer treatment. Regarding total-P, treatment supplied with 100 % N through poultry manure recorded maximum values at all stages of crop growth. All the inorganic fractions of phosphorus exhibited a significantly positive correlation with organic carbon