EFFECT OF POTASSIUM FERTILIZATION ON GROWTH, YIELD AND WATER USE EFFICIENCY OF IRRIGATED POTATO

Abstract

Studies on the effect of K fertilizers application in increasing water use efficiency (WUE) and decreasing the negative effect of water stress, are quite limited, especially under field conditions. A field experiment was conducted in silty clay loam in the Agricultural Research Station of Abu-Graib- Baghdad, Iraq to study the effect of different levels of K fertilizers application on potato (Solanum tuberosumL.( and their role in decreasing negative effect of water stress. Treatments include four levels of K fertilizer (0, 200, 400 and 600 kg K2SO4 ha -1) and two levels of irrigation (after depletion of 50 and 75 % of available water). Results revealed the following:- The negative effects of water stress on potato growth and yield decreased by increased application of K fertilizers. Negative effects of water stress on plant quality and WUE were decreased by increasing level of K fertilizer in depletion 75% of available water, and saving in irrigation water with irrigation scheduling by 9%. 3. Tuber yield, plant height, leaf area and carbohydrates increased with increased K application. Higher K rates improved yield reached to 30.26 and 25.66 t.ha-1 in irrigation with 50 and 75% depletion of available water, respectively. 4. As a conclusion, nutrients application may have a good impact on plant performance under water stress, and decreasing amount of water applied through alterative irrigation improved yield of fruit. Therefore, this experiment signifies the importance of potassium application together with conserving in water application.