Nutrient omission effects on yield, water productivity and profitability of maize (Zea mays)

A 2-year field experiment was conducted during the rainy seasons (July-October) of 2012 and 2013 on a noncalcareous alkaline sandy clay loam soil, to (i) assess the effect of omitted nutrients on growth, yield, water productivity (WP) and profitability of maize (Zea mays L.) crop, and (ii) develop guidelines for the use of soil test crop response (STCR) approach and omission plots, in site-specific nutrient management (SSNM) for targeted and sustained yield of maize in the maize (Zea mays L.)-wheat [Triticum aestivum (L.) emend. Fiori & Paol.] cropping system. The experiment comprised 15 treatments, involving application of N (−PKZn), NP (−KZn), NPK (−Zn) and NPZn (−K) to both maize and wheat crops, to maize and to wheat crop only, absolute control (no nutrient applied), recommended rate of nutrients (120, 60, 40, 5.5 kg/ha N, P, K, Zn) and STCR-based application of nutrients (200, 100, 55, 4 kg/ha N, P, K, Zn). The experiment was set in a randomized complete-block design with 3 replications, in fixed plots. Growth and yield attributes were significantly influenced by nutrient-omission treatments and their values were higher when nutrients were applied according to STCR approach. The STCR-based nutrient application increased dry-matter production and grain yield by 5.9 and 5.7%, respectively over balanced fertilization (recommended doses of NPKZn). Omission of P and K resulted in 9 and 9.7% reduction, respectively, in grain yield of maize. The yield reduction caused by Zn omission was about 3% only. On an average, STCR-based fertilization enhanced water productivity (WP) by over 6.2% compared to balanced fertilization with recommended doses of nutrients. Omission of K in both maize and wheat crops reduced WP by 9.3% compared to recommended doses of NPKZn-applied plot. The highest gross profit of 70, 425/ha was also realized from STCR-based nutrient application.