Fixation and Recovery of Added Phosphorus and Potassium in Different Soil Types of Pulse‐Growing Regions of India

Abstract Fixation and recovery of added phosphorus (P) and potassium (K) were studied in different soil types of pulse‐growing regions. Amounts of P and K fixed increased in all the soils irrespective of type and texture. With the increase in levels of added P and K, maximum P fixation was observed at lower levels of added P (50 mg kg−1). Alfisols showed maximum P‐fixation capacity (92.7%), followed by Vertisols (86.5%) and Inceptisols (76.6%) at 50 mg kg−1 added P. However, K fixation increased with increasing levels of added K up to 200 mg kg−1, and thereafter fixation either decreased or was maintained at similar levels. Vertisols showed higher K fixation than Inceptisols and Alfisols. Fertilizer P requirement per unit increase in available P in soil was highest in Bangalore (3.23) and lowest in Delhi (2.38). Fertilizer K requirement per unit increase in available K in soil was highest in Raipur and Gulbarga (1.75) and lowest in Ranchi (1.28).