The combination of straw return and appropriate K fertilizer amounts enhances both soil health and rice yield in Northeast China

Abstract

AbstractTo identify the ideal potassium (K) fertilization rate in fields with continuous straw return to maintain soil potassium supply and increase yield in the rice‐producing regions of Northeast China, we studied the effect of different K fertilizer application amounts (0, 30, 60, 90, 120, 150, and 180 kg K2O ha−1 yr−1) on rice yield, K use efficiency, and soil K availability in straw‐returned and straw‐removed plots from 2017 to 2019. Results showed that the highest rice yield in straw‐returned plots (60 K2O ha−1) was 3.3% higher than that in the straw‐removed plots (90 K2O ha−1), and the straw‐return treatment attained higher K use efficiencies under low K fertilizer application conditions (30 and 60 kg K2O ha−1). Compared with straw‐removed plots, straw‐returned plots had increased exchangeable K and nonexchangeable K contents in the top 20 cm of soil. The ranges of K fertilizer application amount required to maintain soil K balance (K input–K output) in straw‐returned plots and straw‐removed plots were 48–53 kg ha−1 and 127–140 kg ha−1, respectively. Continuous straw return in rice‐producing regions in Northeast China can decrease K fertilizer application needs by 62.2% compared with straw‐removed plots while simultaneously maintaining soil K balance. Straw return plays an important role in increasing crop yield, preventing soil K depletion, and keeping the development of K resources sustainable.