Evaluating the performance of phosphatic fertilizers on plant nutrients (N, P and K) concentration and uptake by the rice crop

A field experiment was taken up in the farmers’ field at Irumbadi village of Vadipatti block of Madurai district during rabi 2013 with rice (var. ADT 39) as test crop to evaluate the influence of P sources and forms (SSP and complex P with and without PSB) on soil nutrient status, uptake and crop yield. Among the P sources, 20: 20: 0 and PSB (T8) followed by 20: 20: 0 alone (T6) proved significantly superior to SSP and farmers’ fertilizer practice of DAP application. Also the concentration of plant nutrients and their uptake were higher in treatment T8 at tillering, flowering and harvest stages. Application of N and P through complex sources viz., 20: 20: 0 and K through MOP at recommended level or 15: 15: 15 with and without PSB favoured higher total N, P, K and micronutrient contents in grain and straw when compared to other fertilizer sources. The highest P uptake in rice grain (4.28 kg/ha) and straw (4.60 kg/ha) was observed with the application of N and P (150: 50 kg/ha) through complex fertilizers and K through MOP (50 kg/ha) along with PSB (2 kg/ha) resulting in a total uptake of 8.88 kg/ha which was significantly higher over other treatment combinations. The highest concentration of K was recorded in T8 that received complex fertilizer source with PSB and recommended K application of 50 kg/ha during tillering (1.623%), flowering (1.55 2%) and subsequently in grain and straw (1.312 and 1.394%) of rice. It was noteworthy to observe that 100% and 50% of recommended P as SSP were on par in influencing the plant nutrient concentration and uptake indicating the scope for reducing 50% of P in soils of high P availability.