Effect of foliar fertilization of potassium on yield, quality, and nutrient uptake of groundnut

Abstract

Groundnut (Arachis hypogae L.) is the most important oilseed crop of India and it is abundantly grown under rainfed conditions in vertisols of Western India. The objective of this work was to study the effect of potassium (K) basal and foliar fertilization on yield, nutrient concentration in tissue and quality parameters of groundnut. Two varieties, GAUG‐1 (bunch type) and GAUG‐10 (spreading type) were grown during Kharif (rainfed) and Rabi (irrigated) seasons at Junagadh, Gujarat. The experiment compared two foliarapplied K fertilizers (KCl and K2SO4) at two different doses (0.5 and 1.0%) with basal KCl application (0 and 50 kg K2O ha−1). Field soil was highly calcareous (pH 8.2, NH4OAc extractable K 188 kg ha−1 with 40% lime reserve) Vertic ustochrept. The results showed a significant response in pod yield with foliar and soil‐applied potassium as compared to the control treatment. Pod yields were significantly higher when basal and foliar applications were combined. The best results were achieved with foliar application of 1% KCl together with a basal fertilization with 50 kg K2O ha−1. Response to foliar‐applied K was higher in rainfed kharif crop than in irrigated rabi crop. Groundnut variety GAUG‐10 out yielded GAUG‐1. Foliar K application increased plant tissue concentration of K. Foliar fertilization with KCl and K2SO4 did not cause leaf burn. Potassium application improved the crop harvest index and grain quality parameters of boldness, protein and oil contents. Response to K in quality parameters of protein and oil contents of seed was more consistent with foliar applied K2SO4 . The results confirmed that the practice of foliar K nutrition when used as a supplement and not a substitute for standard soil fertilization, is beneficial for groundnut crop in Western India.