TY - JOUR T1 - Kinetics of Non-Exchangeable Potassium Release from Soil and its Components in Some Soils of Golestan Province TT - سرعت آزاد شدن پتاسیم غیر‌تبادلی از خاک و اجزای آن در تعدادی ازخاک‌های استان گلستان JF - JSTNAR JO - JSTNAR VL - 16 IS - 59 UR - http://jstnar.iut.ac.ir/article-1-2213-en.html Y1 - 2012 SP - 273 EP - 285 KW - Non-exchangeable potassium KW - Kinetic equations KW - Soil components N2 - Non-exchangeable potassium (NEK) release is necessary to supply potassium for plant in different soils. A few studies on the NEK release have been done in soils and particularly on its components. This study was intended to investigate the NEK release from soil and the components of clay and silt through successive extractions with oxalic acid (0.01 M) over a period of 1844 (h) in 4 soil series of Golestan province. The amount of NEK release from whole soil, silt and clay fractions after 1844 (h) were 242 to 450, 380 to 550 and 105 to 199 mg kg-1, respectively. The cumulative rates of NEK release after 1844 (h) were well described by simplified Ellovich, parabolic diffusion and power function equations. The rate of K release was high initially, and then decreased gradually in all soils and in their silt and clay fractions. The amount of released NEK (with high rate) consisted of lower percentage of total NEK, but in spite of less amount, this K form plays a vital role in K dynamic and soil fertility. M3 ER -