بررسي وضعيت پتاسيم و اثر خواص فيزيكي و شيميايي خاك بر آن در شاليزارهاي استان گيلان

The Soil potassium status and the effect of physical and chemical properties of soil on it was investigated by the 109 surface soils (0-30cm) from four regions in Guilan province. The Neutral molar ammonium actate extractable K (K-NH4OAc), the boiling molar nitric acid extractable K (K-HNO3) and the water soluble K were determined. The results indicated that the CEC and clay frequency were normally distributed while the distribution frequency of other variables such as silt, organic carbon and pH were not normal (and have significant skewe and kurtosis) and for sand, the K-NH4OAc and K-HNO3 logaritmic distribution was normal. The Water-soluble potassium was affected by sand, pH, O.C and K-NH4OAc (R^2a=0.73**). The Ammonium extractable potassium was affected by soluble potassium, nonexchangable potassium and CEC (R^2a=0.72**). The Boiling nitric acid was affected by the exchangable potassium and silt (R^2a=0.55**). The Geographic distribution of K-NH4OAc data indicated that the amount of it in the central parts of Guilan, particulary sepidrood river water sheed is more than other regions. In the Fomanat region the amount of clay, CECK-NH4OAc and K-HNO3 is less than other regions. According to this study, about the 68.8 percent of Guilan soils is classified in the range of medium to very low potassium status.