Influence of Urea Foliar Nutrition and Leaf Harvesting Intensity on Growth, Yield Attributes and Yield in Cowpea Vigna unguiculta (L.) Walp.

A field experiment was undertaken at Farming Systems Research Station (FSRS), Sadanandapuram, Kollam district, Kerala Agricultural University in summer 2022 for studying the effect of growth, yield attributes and yield of cowpea through foliar application of 2% urea and intensity of leaf harvesting. Experimental treatments comprised of 4 levels of foliar nutrition management (2% urea spray at vegetative stage (f1), 2% urea spray at flowering stage (f2), 2% urea spray at vegetative stage and flowering stage (f3), water spray control (f4) and 3 levels of leaf harvest (20% leaf harvest (l1), 40% leaf harvest (l2), and no leaf harvest (l3). Among the foliar nutrition management treatments, f3 showed significantly the taller plants (91.97 cm), more number of branches (15.13), leaves (34.76), leaf area/ plant (884.29 cm2), leaf area index (1.96) dry matter production (42.39 g) and chlorophyll content (3.544 mg/g) and were comparable with f1. The nodule parameters such as nodule number (37.44) and effective number of nodules (32.11) were the highest in treatment f3 and was on par with f1. Further, days to 50 per cent flowering (53.65 days), pod length (17.27 cm), 100 seed weight (12.40 g), pod number (24.58), foliage yield (1484.57 kg ha-1), grain yield (925.85 kg ha-1) and haulm yield (2722.70 kg ha-1) were the highest in treatment f3 and was on par with f1 except for pod weight (21.19 g). Among the leaf harvest intensity, treatment l3 recorded the taller plants (92.45 cm), leaf area per plant (902.71cm2) leaf area index (2.01), less days to 50% flowering (47.60 days) and haulm yield (2754.85 kg ha-1). It was on par with l1 pertaining to plant height. The number of branches (15.03), dry matter production per plant (40.78g), pod weight/plant (19.43 g), pod number/plant (23.59) and grain yield (925.85 kg ha-1) were the highest in treatment l1.