Limiting Potassium Critical Level in Calcareous Soil- Kurdistan Region

This study was conducted during December 2015 to June 2016 which included a laboratory and a pot experiment and the explaining of the results depended on international researches and the investigations conducted by my PhD student Akrawi (2010), Akrawi and Esmail(2014), Akrawi et al(2016) and my MSc student Hama-Amin(2012).The laboratory experiment was done from August, 2015 to November, 2015, to determine the amount of adsorbed, desorbed, hysteresis and desorption index of potassium for the studied soils.The pot factorial experiment included the effect of 14 different soils in Bitwen plain, 4 level of potassium (0, 30, 60, and 90 mg K+ kg-1 soil) and their combinations on wheat yield, critical level of K+ in the soil and wheat plant using Completely Randomized Design (CRD) with three replicates.The main results were summarized as can be seen on the Summery.