INFLUENCE OF INTEGRATED NUTRIENT MANAGEMENT ON NITROGEN AND PHOSPHORUS IN SOIL UNDER MAIZE- BLACKGRAM-GROUNDNUT CROPPING SYSTEMBellary Ushasri, T. Giridhara Krishna, K.V. Nagamadhuri, Y. Reddi Ramu B. Ravindra ReddyAbstract In order to investigate the immediate effects of integrated use of inorganic and organic sources of N and P on the performance of the maize-blackgram-groundnut cropping sequence in terms of yield, a field experiment was conducted at S.V. Agricultural College Farm, Tirupati during the rabi (maize), summer (blackgram), and kharif (groundnut) seasons of 2019-20. Ten treatments were applied to maize, including the control, fertilizers administered at 50%, 75%, and 100% of the recommended dose (NPK), N240 only, P80 only, FYM (@ 5 t ha-1) applied alone, and in combination with 100%, 75%, and 50% of the recommended NPK. These interventions were contrasted with the manure and no-fertilizer control. Blackgram was produced after maize without the use of fertilizer or manure. It was allowed to mature and expand for two pickings, the stover was incorporated into the soil. In the following rabi season, black gram was grown on the same field, and each main plot treatment of RBD was divided into three sub plot treatments with S1 (control), S2 (75% RDF), and S3 (50% RDF), yielding ninety treatment combinations replicated three times in split plot design . increased fertilizer-N addition rates resulted in increased soil concentrations of ammonia, nitrate, and alkaline KMnO4 oxidisable (available) N. Similar to this, greater Olsen-P and total inorganic P values led to higher fertilizer-P dosages. It was discovered that applying FYM @ 5 t ha-1 and inorganic N together helped to keep the levels of all these types of soil N stable until groundnut harvest. Organic P revealed an inverse relationship with the Inorganic P content at all the growth stages of the three crops under study. |