Effect of different land use on Potassium forms and some soil properties in Kohgiluyeh and Boyer-Ahmad Province, Southwest Iran

The pasture and forest land use change to agricultural use can effect on many properties of the soil and its productivity. The present research aims to investigate various forms of K (soluble, exchangeable, non-exchangeable, and structural forms) and some soil properties in different land use of three areas including Choram, Kakan and Bahmaei in Kohgiluyeh and Buyer-Ahmad Province. Four profiles were excavated in different land use of each area (In total, 12). All profiles were described and classified based on the Keys to Soil Taxonomy. The results showed that there is not any significant positive correlation between the clay and silt contents in different land use, while the lowest content of clay was observed in agricultural land use. The percentage of organic carbon was in its highest level in pasture land use (1.01%), and in its lowest level in agricultural (0.7%) and (0.4%) wheat cultivation. The highest and lowest pH levels were obtained in paddy soil (8.11) and garden (6.8), respectively. The average level of soluble, exchangeable, non-exchangeable, structural and total forms of K in the studied area were 0.5- 6.1, 45-262, 86-366, 835-5197 and 967-5555 mg/kg of the soil, respectively. The studied soils of Kakan and Choram areas had the lowest and highest levels of non-exchangeable, structural, and total forms of K, respectively. In addition, the highest levels of soluble and exchangeable forms of K were observed in Bahmaei and Kakan areas, respectively. The soluble and exchangeable forms of K had significant changes in different land use,