Response of cowpea (Vigna unguiculata) to different irrigation and fertilizer application methods under zero-tilled condition of south Konkan coastal zone of Maharashtra

A field experiment was conducted for 3 consecutive years from 2011–12 to 2013–14 at Dapoli, Dist. Ratnagiri, Maharashtra, to assess the effect of irrigation and levels of fertilizer application on zero-tilled cowpea [Vigna unguiculata (L.)]. The experiment was laid out in a split-plot design with 3 replications. The main plot treatments comprised 3 irrigation levels, viz. no irrigation (I0), 1 irrigation at branching (I1) and 2 irrigations at branching and pod filling stage (I2). The subplot treatments comprised 6 fertilizer levels, viz. no fertilizer (F0), 25% recommended dose of fertilizer (RDF) below seed placement (F1), 50% RDF below seed placement (F2), 75% RDF below seed placement (F3), 100% RDF below seed placement (F4) and 100% RDF through line application (F5). The soil of the experimental plot was uniform, leveled and well drained. It was sandy clay loam, medium in available nitrogen (298.20 kg/ha), low in available phosphorus (11.80 kg/ha), moderately high in available potassium (249.35 kg/ha), high in organic carbon (0.95%) and slightly acidic in reaction. Statistical inferences revealed that application of 2 irrigations (at branching and pod-filling stage) recorded significantly higher growth as well as yield attributes, resulting in higher grain and stover yields followed by the treatment with 1 irrigation (at branching) and control treatment. Application of 100% RDF below seed placement recorded significantly higher growth as well as yield attributes, resulting in higher grain and stover yields followed by 100% RDF through line application and 75% RDF below seed placement over rest of the treatments. Among the different irrigation treatments, application of irrigation at branching and pod-filling stage (?25.5x103/ha) under zero-tilled condition along with 100% recommended dose of fertilizer resulted in significantly higher net returns resulted in (?23.4 x 103/ha) over the control treatment, i.e. F0. The highest benefit: cost ratio was recorded under application of 2 irrigations at branching and pod-filling stage (1.57) along with 100% recommended dose of fertilizer (1.50) which was significantly greater over the control treatment, i.e. F0, where fertilizer were not applied during experimentation.