Influence of irrigation and fertility levels on seed and gum yields, water-use, economics and quality of clusterbean (Cyamopsis tetragonoloba) in Gujarat

A field experiment was conducted during the summer seasons of 2013 and 2014 at Krishi Vigyan Kendra Farm of Junagadh Agricultural University, Nana Kandhasar, Surendranagar, Gujarat, on sandy loam soils to assess the impact of irrigation and fertility levels on growth, yield, water-use, economics and quality of clusterbean [Cyamopsis tetragonoloba (L.) Taub.]. Sixteen treatment combinations of 4 irrigation levels [0.4, 0.6, 0.8 and 1.0 irrigation water: cumulative pan evaporation ratio (IW: CPE) and 4 fertility levels (00: 00, 10: 20, 20: 40 and 30: 60 kg N: P₂O₅/ha) were tested using split-plot design with three replications. The pooled results indicated that irrigation at 0.8 IW: CPE being at par with 1.0 IW: CPE enhanced growth parameters and yield attributes and thereby seed yield (1.33 t/ha), stover yield (2.84 t/ha) and harvest index (31.9%) with the highest net returns ( 53, 895/ha) and benefit: cost ratio of 2.29 over 0.4 IW: CPE. The maximum consumptive use of water was noticed under 1.0 IW: CPE, while the maximum water-use efficiency (WUE) (4.90 kg/ha-mm) and water-expense efficiency (WEE) (4.19 kg/ha-mm) were recorded under 0.4 IW: CPE. Significantly higher protein content (24.3%), protein yield (325 kg/ha), gum content (29.3%) and gum yield (391 kg/ha) were recorded under 0.8 IW: CPE over 0.4 and 0.6 IW: CPE. Application of 20: 40 kg N: P₂O₅/ha being at par with 30: 60 kg N: P₂O₅/ha also improved growth parameters, yield attributes, seed yield, stover yield, harvest index with the highest net returns ( 52, 967/ha) and benefit: cost ratio of 2.24 along with consumptive use of water, WUE, WEE, protein content, protein yield, gum content and gum yield than control. Therefore, irrigation at 0.8 IW: CPE and fertilizer dose of 20: 40 kg N: P₂O₅/ha could be applied for higher yield and monetary returns from clusterbean (gumguar) along with appreciable saving of water and fertilizer in summer season.