Two field experiments were conducted for two years (2000 and 2001) at Agronomic Research Area, University of Agriculture Faisalabad (UAF), Pakistan. There were 15 treatment combinations for experiment-I having three plant densities, viz., one seedling hill-1 (PD1), two seedlings hill-1 (PD2) and three seedlings hill-1 (PD3) and five nitrogen rates, viz., 0, (N0); 50, (N50); 100, (N100); 150, (N150); and 200 (N200) kg N ha-1. Experiment-II also included 15 treatments having three plant densities, viz., one seedling hill-1 (PD1), two seedlings hill-1 (PD2) and three seedlings hill-1 (PD3) and five irrigation regimes, viz., 62.5 cm (I1), 77.5 cm (I2), 92.5 cm (I3), 107.5 cm (I4), and 122.5 cm (I5). A randomized complete block design (RCBD) was employed with three repetitions. The results for experiment-I revealed that the highest biomass (1438 g m-2), grain yield (497 g m-2), crop growth rate (15.36 g m-2 d-1), net assimilation rate (4.24 g m-2 d-1) were observed in the treatment having combination of two seedlings hill-1 and 200 kg N ha-1 (PD2N200). The agronomic and economic nitrogen and PAR use efficiencies were also higher in this treatment. In case of experiment-II, the highest biomass and grain yield were obtained in case of treatment having combination of two seedlings hill-1 and 107.5 cm irrigation regime (PD2I107.5). The irrigation application based water productivity ranged from 0.36 kg mm-3 to 0.61 kg mm-1, irrigation plus precipitation based water productivity ranged from 0.32 kg mm-3 to 0.55 kg mm-3 and evapotranspiration based water productivity ranged from 0.65 kg mm-3 to 0.84 kg mm-3 among 15 treatments combination of plant density and irrigation regimes. This study concludes that for increasing the benefits for the resource-poor growers, the integration of crop management practices is an optimum strategy to substantially increase the resources use efficiency under irrigated semiarid environment.
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