Fertilizer Phosphorus Solubility Effects on Indian Mustard–Maize and Wheat–Soybean Cropping Systems Productivity

Abstract

In Indian mustard and wheat, newly developed phosphorus fertilizers, Suphla of 20:20:0 grade with 60 and 80% water solubility were comparable with di‐ammonium phosphate for crop productivity. Residual effect of newly developed phosphorus fertilizers sources was significant in succeeding maize and soybean crops. All P sources were found equally effective and recorded higher yields and nutrient uptake compared to omission of P. Phosphorus fertilizer sources, Suphla of 20:20:0 grade with 60 and 80% water solubility can be used to meet out the P requirement of mustard–maize and wheat–soybean systems. Crop responses to P fertilization, in terms of productivity, phosphorus‐use efficiency (PUE), and residual fertility in soil, can depend on the form of P applied. A field experiment was conducted to determine the effect of various P fertilizer forms on productivity and PUE indices in two predominantly practiced Indian mustard [ Brassica juncea (L.) Czern & Coss.]–maize [ Zea mays (L.)] and wheat [ Triticum aestivum (L.) emend. Flori & Paol]–soybean [ Glycine max (L.) Merrill] cropping rotations. The experiment was conducted during 2012–2014 at the Indian Agricultural Research Institute, New Delhi, India. A ‘Suphala’ P fertilizer, with 30, 60, and 80% water solubility was compared with single superphosphate (SSP) and di‐ammonium phosphate (DAP), all including the recommended dose of N and K through urea and muriate of potash. The seed yield (6.0—21.3%), crop equivalent yield (4.7–10.3%) and system net returns (1.8–11.8%) of Indian mustard were higher with direct application of SSP over other soluble and partially soluble P fertilizers. Wheat yield (4.6–9.6%) and system net returns (2.7–9.6%), were higher using DAP. However, the residual effect of P fertilizers exerted a significant influence on the performance of succeeding maize and soybean crops. Using DAP as P fertilizer form recorded higher grain yield and system net returns of maize and soybean than other soluble P forms. Irrespective of the fertilizer form, treatments involving P application improved P use indices, and apparent N and K recovery in Indian mustard and wheat crops. Hence, the studied P fertilizer forms will result in higher productivity, sustainable use of resources and reduction in production costs for these cropping systems.