Interactive Effects of Potassium Fertilization and Rice Residue Management on Soil Potassium Fractions in a Rice-Rice Cropping System

Abstract

Soil potassium (K) dynamics are strongly influenced by fertiliser and crop-residue management in intensive rice systems. A field experiment was conducted at the Agricultural Research Station, Tornala, Telangana, India, during rabi 2024-25 and kharif 2025 to evaluate the effects of potassium fertilisation and rice-residue management on soil K fractions in a rice–rice cropping system. The experiment comprised nine treatment combinations involving three K levels (0, 50 and 100% of the recommended K dose) and three residue-management practices (removal, incorporation and burning), laid out in a randomised block design with three replications. Water-soluble, exchangeable, non-exchangeable and total K were determined at tillering, panicle initiation and harvest. Residue incorporation consistently maintained greater K pools than residue removal, while burning produced intermediate values. Application of 100% recommended potassium fertiliser coupled with residue incorporation maintained the highest K status, whereas residue removal coupled with omission of fertiliser potassium recorded the lowest. At harvest, treatments receiving 100% recommended potassium fertiliser coupled with residue incorporation maintained 70.9, 36.4, 44.5 and 26% greater water-soluble, exchangeable, non-exchangeable and total K, respectively, than residue removal treatments.  Residue incorporation also improved K pools without fertiliser K, highlighting the contribution of residue-derived K recycling. Overall, integrating adequate K fertilization with residue incorporation effectively maintained both labile and reserve K pools, thereby strengthening soil K-supplying capacity and environmental sustainability under intensive rice–rice cultivation.