STATUS OF K IN SOIL FOR PLANT GROWTH

Abstract

Fertilizer is a vital input for food production and it should be used efficiently in order to minimize food production cost as well as to conserve natural resources. In developing countries crop yield are low either due to the lack of fertilizer or inefficient use of fertilizers. In Pakistan, the response of crop to applied K is unpredictable due to lack of refined critical level of soil K and this unpredictability is further intensified due to different adsorption characteristics of various soils for K. As fertilizer the fate of added K depends upon the initial level of soil K. The concentration of K in soil solution depend on the rapidity at which desorption of K can be occurred from the adsorption phase and the rate of removal by the plants, whereas adsorption equilibrium solution K level serve as a key of K availability. The response of crops to K considerably depends on the original status of the K, the status of initial soil K concentration must be considered before K fertilizer application. In the Indus plain of Pakistan, soils contain 2.65 to 3.55 % K. in the surveyed area of Pakistan more than half of the soils are categorized as Aridisols, under this situation crop response to K fertilizer are very unbalanced and intermittent because scientifically based critical soil K level did not exist.