NUTRIENT BALANCES AS AFFECTED BY INTEGRATED NUTRIENT AND CROP RESIDUE MANAGEMENT IN COTTON-WHEAT SYSTEM IN ARIDISOLS. III. POTASSIUM

Potassium (K) uptake, uptake trend and apparent balances as influenced by integrated nutrient and crop residue management were investigated in a five-year field experiment on two calcareous soils, i.e., Awagat (coarse loamy) and Shahpur (fine silty) in cotton-wheat sequence. Total K uptake by cotton and wheat plants differed significantly due to nutrient management treatments, i.e., farmers' fertilizer use (FFU); balanced nutrient management (BNM); integrated nutrient management (INM); and balanced nutrient management plus green manuring (BNM+GM). Minimum mean K uptake (kg ha(-1)) by cotton with FFU was 87.1 in Awaga and 108.1 in Shahpur. Corresponding maximum mean K uptake with INM was 115.1 and 132.2, respectively. Nutrient treatments effect on K uptake by wheat was similar to cotton. Potassium uptake was further enhanced by crop residue recycling. Potassium uptake by both crops exhibited non-significant trends and large negative apparent K balances were observed in both the soils.