Potassium Availability in Soils,Crop Response and Evidence-based Approach for Rationalizing its Use in Crops

摘要

Despite the natural abundance of potassium(K)in the soils in certain regions of the world,crop K deficiencies are prevalent over large areas due to particular pedoclimatic conditions or chronic under-fertilization of K.Globally,the K replenishment in agricultural soils is only between 10 and 35 of the crop K removed.Consequently,K is as limiting as nitrogen(N)and phosphorus(P)for plant productivity,and some degree of K limitation was observed up to 70 in all terrestrial ecosystems examined.Potassium management in crops in India follows the same trend.General perception of high K content in Indian soils and the cost of K fertilizers often deter farmers to apply adequate K to crops.Sustained removal of soil K in absence of adequate inputs created large negative input-output balance and promoted K mining in India.Evidences from nationally coordinated research programmes corroborate losses in yield and income associated with inadequate K use in crops.Furthermore,research in India and elsewhere supports site-specific K management and provides strategies to rationalize its application in crops and cropping systems.Field implementation of such strategies is essential to maintain the crop yield trajectories for future food and nutrition security,particularly under adverse climate impacts.