The Challenge of Alleviating Potassium Limitation in Major Cropping Systems of Southeast Asia

Abstract Potassium (K) has received less attention than nitrogen (N) and phosphorous (P) as a potential yield-limiting factor in cropping systems. Here we investigated the current K limitation in intensive cereal cropping systems of Southeast Asia based on nutrient balances, leaf nutrient status, long- and short-term fertilizer trials, and farmer surveys. We found that soil K alone cannot meet plant requirements and current fertilizer application is insufficient to avoid plant K deficiencies and large negative soil K balances in farmer fields. Removing the K limitation requires improved capacity to predict response to K fertilizer together with long-term, flexible fertilizer and crop straw management strategies. It is likely that similar K limitations have emerged in other world regions as a result of decades of intensive cropping with insufficient replenishment of potassium, which represent headwinds to closing yield gaps on existing farmland.