Effect of Levels of Potassium on Yield Attributes, Seed and Stover Yield, and Uptake of Nitrogen, Phosphorus and Potassium by Mustard (Brassica juncea L.) Grown in Black Cotton Soil

Abstract:

A field experiment was conducted during the rabi season of 2025-26 at AICRP Mustard, College of Agriculture, Nagpur, on a black cotton soil (Vertisol) to study the effect of graded levels of potassium on yield attributes, seed and stover yield, and the uptake of nitrogen, phosphorus and potassium by mustard (Brassica juncea L.) variety PDKV-Kartik. The experiment was laid out in a Randomized Block Design with seven treatments T1: absolute control, T2: RDF (50:40 kg N:P ha⁻¹), and T3 to T7 comprising RDF supplemented with 10, 20, 30, 40 and 50 kg K ha⁻¹, respectively replicated thrice. Application of potassium significantly and progressively improved yield-attributing characters, with the number of siliquae plant⁻¹ and test weight rising from 175.53 and 4.64 g under the control to a maximum of 258.40 and 5.23 g, respectively, at the higher potassium levels. Seed yield increased from 10.55 q ha⁻¹ (T1) to 16.62 q ha⁻¹ (T7), and stover yield increased from 28.48 q ha⁻¹ (T1) to 45.69 q ha⁻¹ (T7). Total nitrogen, phosphorus and potassium uptake by the crop (seed + stover) also increased consistently with potassium application, from 55.70, 14.50 and 30.72 kg ha⁻¹ under the control to 103.03, 34.20 and 61.60 kg ha⁻¹, respectively, under T7 (RDF + 50 kg K ha⁻¹). The results indicate that balanced fertilization with nitrogen and phosphorus along with an adequate dose of potassium (up to 50 kg K ha⁻¹) is essential for realizing higher yield and nutrient-use efficiency in mustard grown on potassium-fixing black cotton soils of the Nagpur region.