Potassium Deficiency in Soils and Crops: Emerging Soil Fertility Constraint in Dryland Agriculture

Abstract

Agriculture is the back bone of Indian economy with about two thirds of the population residing in rural areas directly or associated it for their livelihood and contributing to 19% of the Gross Domestic Product. The relative slow increase in agricultural production in recent years as compared to the quantum jump witnessed during the period of green revolution has become a mater of concern for the entire nation. Intensification of agriculture has caused serious strain on the soil system. The soils are showing fatigue ness and factor productivity is declining. The two important factors come in our way of further intensification are soil fertility and environmental safety. With the initiation of green revolution in late seventies, India has made remarkable progress in food security, poverty reduction and per capita income. Even though India has made considerable progress over the years in increasing the food grain production to a recent 217 mt in 2008-09, the performance over the last ten years has been unsatisfactory. The growth rate in agriculture has not kept pace with the phenomenal growth rate in industrial and services sectors. Obviously a concerted effort is required to improve the condition of Indian Agriculture, which involves policy intervention, frontier research, publicprivate partnership, and involvement of farmers at different stages starting from technology generation to its adoption. Soil fertility and its evaluation is one area which needs immediate attention since it is now established that an arrest in the productivity of several crops is due to ever decreasing soil fertility on one hand and an imbalanced application of plant nutrients on the other. The deficiency of several major and minor plant nutrients such as K, S, Ca, Zn. Fe and B are emerging in time and space. Among the essential plant nutrients, potassium assumes greater significance since it is required in relatively larger quantities by plants and besides increasing the yield, it immensely improves the quality of the crop produce. Most the literature in the past indicated the sufficiency of K in Indian soils, but continuous intensive production systems with K supply resulted in depletion of soil K reserves. Potassium nutrition has special significance in dryland agriculture as it regulates water relations under moisture stress environment. This document covers K status in rainfed regions of India, role of K in drought tolerance, K additions, K removals under intensive systems, K deficiency in different crop plants, nutrient recommendations, on farm impacts of K application on field crops, vegetables and fruit crops. Information regarding potassium deficiency symptoms and impacts are useful to farmers to identify K deficiency in the field and so for the extension specialists, line departments, policy makers and soil fertility researchers.