Fertigation and mulching studies in yard long bean (Vigna unguiculata var-sesquipedalis (L.) verdcourt)

Abstract

The investigations on ‘Fertigation and mulching studies in yard long bean (Vigna unguiculata var. sesquipedalis (L.) Verdcourt)’ were carried out in the Department of Olericulture, College of Horticulture, Vellanikkara during January –May 2014. The study was conducted in the yard long bean variety Vellayani Jyothika to standardize the fertigation requirement and to assess the relative efficacy of fertigation and mulching over the conventional method. The experiment was laid out in strip plot design with two replications. There was a total of 17 treatments consisting of combinations of two irrigation levels (60 and 80 per cent pan evaporation (Ep) through drip irrigation) and four fertilizer levels (75, 100 and 125 per cent recommended dose of fertilizer (RDF) and 100 per cent RDF with water soluble fertilizer) with and without mulching and a control treatment (channel irrigation once in three days with 100 per cent RDF). The study revealed that irrigation, mulching and fertilizer levels had significant effect on vine length. Scheduling of irrigation at 80 per cent Ep resulted in significantly higher vine length. At higher levels of irrigation (80 per cent Ep) yield and number of pods per plant were higher whereas, length and weight of pods, and number of seeds per pod were not influenced by the levels of irrigation. Mulching significantly influenced yield and yield attributing characters like number of pods per plant, and length and weight of pods but had no influence on number of seeds per pod and protein content of pods. Plants receiving 125 per cent RDF resulted in significantly higher yield and yield attributing characters like number of pods per plant, number of seeds per pod, length and weight of pods compared to 75 and 100 per cent RDF. Per se and interaction effects of irrigation, mulching and fertilizer were not significant with respect to days to first flowering, first fruit set, first harvest, days from flowering to harvest, number of harvests, duration of the crop and protein content. Weed growth in terms of fresh and dry weight was not influenced by levels of irrigation while mulched plots recorded significantly lower weed growth than the unmulched plots. Among the fertilizer levels, 125 per cent RDF resulted in higher weed growth. Organic carbon content, available nitrogen, available phosphorus and available potassium on 45 DAS and at final harvest were the highest in treatments receiving 125 per cent RDF whereas, the highest pH and the lowest EC were recorded in 75 per cent RDF. Interactions between levels of irrigation, mulching and fertilizer when considered together, had significant effect on vine length, all yield attributes, weed growth and all soil parameters. The vine length, yield, yield attributes like length and weight of pods and soil nutrients were the highest when irrigation was given at 80 percent Ep along with mulching and 125 per cent RDF (I1M1F3). This was statistically on par with the treatment I2M1F3 in which irrigation was limited to 60 per cent Ep. An increase of 3.4 times was there in yield in the treatments I1M1F3 and I2M1F3 over conventional channel irrigation at 3 days interval with 100 per cent RDF (control). The highest BC ratio of 1.83 was obtained for the treatments I1M1F3 and I2M1F3 (60 and 80 per cent Ep with mulching, 125 per cent RDF). Irrigation at 60 or 80 per cent Ep along with 125 per cent RDF and mulching with white on black polythene was found to be the best treatments.