بررسي مقدار هدررفت عناصر غذايي پرمصرف در اثر فرسايش خاك در اراضي شيب دار زير كشت چاي در شرق استان گيلان

Nutrient loss due to soil erosion in stop lands

Erosion damages are not limited only to soil loss and deposition of soil in water resources but nutrient loss is also one of the main damages caused by it. This study, which is conducted in steep slope tea lands with sandy textures, is aimed at finding the amount of nutrient loss (N.P.K) and its economic value. Using Cs-137 technique and zhang equation, average erosin on rate was found to be 3 ton/ha/yr. The amount of total N. and available P and K which were lost because of erosion are found to be 1.21 0.26 and 0.75 kg/ha/yr. The cost of the lost available nutrient amount to 1450 Ris/ha/yr. The results show that erosion plays an important role in the depletion of soil of nutrients and the economic value of the lost nutrients in very high. Nutrient loss is also a major factor in the pollution of water resources. Therefore, earring out soil conservation projects is a necessity.