Foliar Nutrition with Water Soluble Macro and Micro Nutrient Fertilizers for Yield Maximization in Bush Vegetable Cowpea

Abstract

Background: Cowpea is a leguminous crop of indeterminate growth habit and continues to produce flowers throughout its life cycle. In order to realize the genetic yield potential of cowpea, nutrient requirements of later formed flushes also needs to be met. Hence the present study was formulated to assess the effect of foliar application of water-soluble macro nutrient fertilizers viz., NPK 19:19:19 and potassium nitrate and micronutrient fertilizers viz. zinc sulphate and solubor for yield maximization in bush vegetable cowpea. Methods: The field experiment was conducted at Coconut Research Station, Balaramapuram, during Rabi 2020-21. The experiment was laid out in randomized block design with 13 treatments in three replications. The treatments comprised of recommended dose of conventional fertilizers (RDF) NPK 20:30:10 kg ha-1 as control and RDF + foliar application of water-soluble fertilizers 19:19:19 (0.5%) and potassium nitrate (0.5%) with zinc sulphate (0.05%) and solubor (0.025%) in twelve different combinations. Result: Results revealed that compared to RDF alone, RDF + foliar application of water-soluble macro and micro nutrient fertilizers at 45 DAS significantly improved the dry matter production, number of pods per plant and pod weight and recorded a yield enhancement of 22 to 55 per cent. Among the treatments, RDF + foliar application of 19:19:19 (0.5%) and solubor (0.025%) at 45 DAS recorded the highest dry matter production per plant (39.51 g), pods per plant (30.88 no.), pod yield (7410 kg ha-1), net return (82651 Rs ha-1) and B:C ratio (2.26). The treatments, RDF + foliar application of 19:19:19 (0.5%) at 45 DAS; RDF + foliar application of 19:19:19 (0.5%), zinc sulphate (0.05%) and solubor (0.025%) at 45 DAS; and RDF + foliar application of potassium nitrate (0.5%) and solubor (0.025%) at 45 DAS also recorded comparable number of pods per plant, green pod yield, net return and B:C ratio. Considering the highest green pod yield, net return and B:C ratio, RDF + foliar application of NPK 19:19:19 (0.5%) and solubor (0.025%) at 45 DAS could be recommended for yield maximization in bush type vegetable cowpea.