Nodule Parameters, Quality and Nutrient Uptake of Vegetable Cowpea [Vigna unguiculata subsp. unguiculata (L.) Verdcourt] as Influenced by Foliar Application of Macro and Micro-nutrients

Abstract

Background: Legumes are one of the major sources of dietary proteins for the people of India and is an inevitable component of vegetarians’ diet. Among them cowpea pods and seeds are rich source of protein and accrue delicacy in cuisines. Adequate amounts of fertilizers applied through most effective and economic means can raise productivity and profitability of cowpea cultivation. Hence the present study was formulated with an objective to study the effect of water-soluble macro and micro nutrient fertilizers on nodulation, quality and nutrient uptake of vegetable cowpea. Methods: Field experiment was conducted at Coconut Research Station, Balaramapuram during the period from 12 November 2020 to 31 January 2021. The experiment was laid out in randomized block design with 13 treatments in 3 replications. The treatments comprised of recommended dose of fertilizers (RDF) as control and RDF + foliar application of NPK 19:19:19 (0.5%) or potassium nitrate (0.5%) alone or in combination with ZnSO4 (0.05 %) and solubor (0.025%). Result: Foliar nutrition of micro and macro nutrients had significant effect on nodulation, quality and nutrient uptake. Foliar nutrition of 19:19:19 resulted in the production of higher number of nodules than KNO3. Among the treatments, RDF (20:30: 10 kg NPK ha-1) + foliar application of 19:19:19 (0.5% ) + solubor (0.025% ) at 45 DAS resulted in higher number of nodules and nodule fresh weight per plant, however higher number of effective nodules was recorded in RDF + foliar nutrition of 19:19:19 (0.5%) alone at 45 DAS. The highest uptake of N, P and K by the crop was also recorded in RDF + foliar application of 19:19:19 (0.5%) + solubor (0.025%) at 45 DAS. Zinc uptake was the highest in RDF + foliar application of KNO3 (0.5%) 45 and 60 DAS and B uptake was the highest in RDF + foliar application of KNO3 (0.5%) + solubor (0.025%) at 45 DAS. The highest crude protein content was recorded in RDF + foliar nutrition of 19:19:19 (0.5%) + ZnSO4 (0.05%) and solubor (0.025%) at 45 DAS fb 19:19:19 (0.5%) at 60 DAS. The treatment, RDF + foliar application of 19:19:19 (0.5%) + solubor (0.025%) at 45 DAS resulted in the highest number of pods and green pod yield per plant in bush type vegetable cowpea.