Integrated management of irrigation water and fertilizers for wheat crop using field experiments and simulation modeling

The reported study aimed at developing an integrated management strategy for irrigation water and fertilizers in case of wheat crop in a sub-tropical sub-humid region. Field experiments were conducted on wheat crop (cultivar Sonalika) during the years 2002-2003, 2003-2004 and 2004-2005. Each experiment included four fertilizer treatments and three irrigation treatments during the wheat growth period. During the experiment, the irrigation treatments considered were I-1 = 10% maximum allowable depletion (MAD)of available soil water(ASW): I-2 = 40% MAD of ASW; I-3 = 60% MAD of ASW. The fertilizer treatments considered in the experiments were F-1 = control treatment with N:P2O5:K2O as 0:0:0 kg ha(-1), F-2 = fertilizer application of N:P2O5:K2O as 160:80:80 kg ha(-1): F-3 = fertilizer application of N:P2O5:K2O as 120:60:60 kg ha(-1) and F-4 = fertilizer application of N:P2O5:K2O as 160:80:80 kg ha(-1). In this study CERES-wheat crop growth model of the DSSAT v4.0 was used to simulate the growth(,) development and yield of wheat crop using soil, daily weather and management inputs, to aid farmers and decision makers in developing strategies for effective management of inputs. The results of the investigation revealed that magnitudes of grain yield, straw yield and maximum LAI of wheat crop were higher in low volume high frequency irrigation (I-1) than the high volume low frequency irrigation (I-3). The grain yield, straw yield and maximum LAI increased with increase in fertilization rate for the wheat crop. The results also revealed that increase in level of fertilization increased water use efficiency (WUE) considerably. However, WUE of the I-2 irrigation schedule was comparatively higher than the I-1 and I-3 irrigation schedules due to higher grain yield per unit use of water. Therefore, irrigation schedule with 40% maximum allowable depletion of available soil water (I-2) could safely be maintained during the noncritical stages to save water without sacrificing the crop yield. Increase in level of fertilization increases the WUE but it will cause environmental problem beyond certain limit. The calibrated CERES-wheat model could predict the grain yield, straw yield and maximum LAI of wheat crop with considerable accuracy and therefore can be recommended for decision-making in similar regions. (C) 2009 Elsevier B.V. All rights reserved.