Optimizing nutrient and irrigation requirement of sugarcane (Saccharum species hybrid complex) and French bean (Phaseolus vulgaris) intercropping system

摘要

A field experiment was conducted during 2010-13, on a sandy-loam soil at Pusa, Bihar to find out optimum nutrient and irrigation requirement of French bean (Phaseolus vulgaris L) when intercropped with autumn sugarcane (Saccharum spp. hybrid complex).Fifteen treatment combinations consisted of 5 fertility levels [sugarcane + French bean (1: 2) with 100% recommended dose of fertilizer (RDF) to both the crops and residue incorporation, sugarcane + French bean (1: 2) with 100% RDF to sugarcane and 50%RDF to French bean and residue incorporation, sugarcane + French bean (1: 2) with 100% RDF to sugarcane and 100% N to French bean and residue removal (existing recommendation), sugarcane + French bean (1: 2) with 100% RDF to sugarcane and 100% N and P toFrench bean and residue incorporation, sugarcane + French bean (1: 2) with 100% RDF to sugarcane and 100% N and K to French bean and residue incorporation) and 3 irrigation schedules [no irrigation, 1 irrigation at 45 days after sowing (DAS) and 2 irrigations at 45 and 75 DAS] were evaluated in factorial randomized block design with 2 additional treatments as sole sugarcane and sole French bean. Application of 100% RDF to sugarcane and French bean with residue incorporation produced significantly higher grain (1.15 t/ha) and haulm yield (1.90 t/ha) of French bean. The treatments of sugarcane + French bean with 100% RDF to both the crops and residue incorporation, sugarcane + French bean with 100% RDF to sugarcane and 100% N and K to French bean and residue incorporation and sugarcane + French bean with 100% RDF to sugarcane and 100% N and P to French bean and residue incorporation being similar noticed significantly enhanced cane-equivalent yield (100.0, 95.8 and 94.8 t/ ha), gross returns (^2,29,400; 2,19,600 and 2,17,300/ ha), net returns (^1,41,900; 1,33,100 and 1,30,100/ha) and benefit: cost ratio (2.62, 2.53 and 2.49), respectively, over rest of the treatments. The same treatment also accounted for higher land-equivalent ratio, area-time equivalent ratio and N, P and K uptake of sugarcane and French bean with greater available N, P and K status in post-harvest soil. Among the irrigation schedules, the highest cane yield (89.0 t/ha), French bean grain (1.20 t/ha), haulm yield (1.98 t/ha) and cane equivalent yield (106.0 t/ha) were recorded in treatment that received 2 irrigations at 45 and 75 DAS. Similarly, the maximum land-equivalent ratio, area time-equivalent ratio, gross returns, net returns, benefit: cost ratio and N, P and K uptake wasnoted from the enhanced levels of irrigation. The sugar yield was significantly increased with each successive increase in level of irrigation. Considering the total productivity and economics, sugarcane + French bean (1: 2) with 100% RDF to sugarcane and 100% N and K to French bean and residue incorporation, could be adopted under similar agro-ecological situations with twice irrigation up to the period of French bean at 45 and 75 DAS and normal irrigation for sugarcane after harvest of French bean.