Yield, nutrient uptake and economics of Indian mustard (Brassica juncea) as affected by split and foliar application of potassium

A field experiment was carried out during winter (rabi) season 2021–22 at the ICAR-Indian Agricultural Research Institute located at New Delhi to find out the effect of potassium management on yields, nutrient uptake and economics of Indian mustard. Eight treatments combinations of different doses, methods and time of potassium application i.e. No K = 0 kg K/ha; 100% MOP (muriate of potash) as basal; 2 Foliar sprays of KNO3 at branching and before flowering; 50% MOP as basal + 50% MOP as top dressing at branching; 50% MOP as basal + 2 foliar sprays of KNO3 at branching and before flowering; 75% MOP as basal + 25% MOP as top dressing at branching; 75% MOP as basal + one foliar spray of KNO3 at branching; 75% MOP as basal + one foliar spray of KNO3 before flowering were tested. Grain (1.89 t/ha) and straw yields (6.74 t/ha), harvest index (21.88%) and NPK uptake (93.9, 18.5 and 113.3 kg/ha) were significantly higher under 75% MOP as basal + one foliar spray of 2.5% KNO3 before flowering. However, the treatment i.e. 75% MOP as basal + one foliar spray of KNO3 before flowering remained significantly at par with 75% MOP as basal + one foliar spray of KNO3 at branching and 75% MOP as basal + 25% MOP as top dressing at branching in yield and profitability term. Enhanced net returns amounting to 65,873/ha and a benefit: cost ratio of 1.86 were recorded on the application of 75% MOP as basal fertilizer combined with a single foliar spray of KNO3 before flowering. This remained comparable to most treatments, except the control, 100% MOP applied as basal, the method involving two foliar sprays of KNO3 at branching and before flowering, 50% MOP as basal combined with 50% MOP as top dressing at branching, and the approach combining 50% MOP as basal with 2 foliar sprays of KNO3 at branching and before flowering.