Performance of Cluster Bean (Cyamopsis tetragonoloba) under Varying Levels of Irrigation and Nitrogen

Background: Clusterbean (Cyamopsis tetragonoloba L.) is important commercial crop which belongs to family Leguminosae and has capacity to fix the atmospheric nitrogen. The nitrogen fixed by the legume crop is not enough to meet the demand of short duration crop like clusterbean. Besides, the experimental site falls under arid region where drought stress and poor distribution of rain during the crop growing cycle is common which affects the crop growth and productivity. Drawing on these insights, the study was planned to assess the performance of cluster bean with objectives to quantify water balance and to calculate suitable levels of irrigation and nitrogen. Methods: The experiment was conducted at research farm, Agricultural research sub-station, Hanumangarh, Swami Keshwanand Rajasthan Agricultural University, Bikaner during Kharif, 2016. Cluster bean variety RGC-1055 with seed rate of 16 kg ha-1 was planted with 3 levels of irrigation (100, 200 and 300 mm) and 4 levels of nitrogen (0, 20, 40 and 60 kg ha-1) and analyzed in split plot design with three replications. Result: Results showed by that the irrigation and nitrogen application rates significantly influenced the growth parameters, yield, nitrogen content and uptake by cluster bean. Irrigation level 200 mm significantly increased leaf area index at 60 DAS (2.62), dry matter accumulation (DMA) at 60 DAS and harvest (16.51 and 42.62 g plant-1), crop growth rate at 30-60 DAS and at harvest (0.36 and 0.62 g m-2 day-1), relative growth rate at 60- at harvest (1.59 g g-1 day-1), grain yield (1624 kg ha-1), straw yield (3645 kg ha-1) and biological yield (5270 kg ha-1) over irrigation level 100 mm, but statistically at par with irrigation level 300 mm. However, leaf area index at harvest (1.24) was highest at 300 mm irrigation level. Nitrogen level at 40 kg ha-1 significantly increased leaf area index at 30, 60 DAS and at harvest (0.19, 2.65 and 1.16), dry matter accumulation at 60 DAS and at harvest (19.62 and 49.58 g plant-1), crop growth rate at 30-60 DAS and 60- harvest (0.46 and 0.71 g m-2 day-1), relative growth rate at 30-60 DAS and 60-harvest (1.26 and 1.66 g g-1 day-1), grain yield (1668 kg ha-1), straw yield (3696 kg ha-1) and biological yield (5364 kg ha-1) over control. The highest nitrogen content and uptake in grain and straw was obtained with irrigation level at 300 mm and nitrogen level @ 60 kg ha-1.