Effect of different potassium levels application on residual effect and potassium status crops in wheat-corn-wheat rotation

In view of attention to the key role of potassium in wheat production and its complicated behaviour in soil as well,and in order to study the effect of application of different amount and resources of potassium and the possibility use of potassium fixation capcity index in estimation of crop needs in wheat-corn-wheat rotation. This experiment was investigated in Ahvaz and Behbahan areas. The experiment design was a complete randomized block design. Frtilizer resources were potassium sulphate and chloride. The treatments were at fixed plots and were as follows: 1-control(whithout consumption of K fertilizer) 2-Application of K based on 100 kg\\ha K2O from potassium sulphate resource in any crop of rotation 3- Application of K fertilizer based on 100 kg\\ha K2O from potassium chloride resource in any crop of rotation 4- Application of K based on soil testing from potassium sulphate resource in any crop of rotation 5- Application of potash fertilizer based on soil testing from potassium chloride resource in any crop of rotation 6- Application of K based on twice soil testing recommendation from potassium sulphate resource in any crop of rotation 7- Application of K based on twice soil testing recommendation from potassium chloride resource in any crop of rotation 8- Application of K based on soil testing recommendation plus 20% soil potassium fixation capacity from potassium sulphate resource in any crop of rotation 9- Application of K based on soil testing recommendation plus 20% soil potassium fixation capacity from potassium chloride resource in any crop of rotation 10- Application of K based on twice soil testing recommendation only in the first crop of rotation and for the following crop based on soil testingfrom potassium sulphate resource 11- Application of K based on twice soil testing recommendation only in the first crop of rotation and for the following crop based on soil testingfrom potassium chloride resource The results were analyzed using statistical software as mstatc and indicated that there were significant effects between the yield and amount of different forms of potassium in various treatments. The most yield of wheat in Ahvaz region belonge to soil test plus 20% K fixation capacity and twice soil testing treatments. In Behbahan soil test plus 20% K fixation capacity from potassium chloride resource was the best treatment.