Potassium Fertilization in Cluster Bean–Mustard and Pearl Millet-Mustard Cropping Systems

A field study was carried out on a loamy sand soil of southern Haryana for six years to study the effect of potassium application (0, 20, 40 and 60 kg K2O ha−1 applied in kharif) on growth, yield, K uptake and available soil K status in cluster bean-mustard and pearl millet-mustard cropping systems. The results revealed that cluster bean and pearl millet crops responded significantly up to 20 and 40 kg K2O ha−1 while its residual effect in mustard crop was significant at 40 and 60 kg K2O ha−1 in cluster bean-mustard and pearl millet-mustard cropping systems, respectively. The potassium application significantly increased K uptake by cluster bean, pearl millet and mustard crops. The mean available K status of soil (160 kg ha−1) decreased to 125, 140, 148 and 155 kg ha−1 after harvest of continuous six years of cluster bean-mustard and pearl millet-mustard cropping systems with application of 0, 20, 40 and 60 kg K2O ha−1, respectively.