[Characteristics of nitrogen loss from sloping field in red soil area under different cultivation practices]

The characteristics of nitrogen loss under six types of cultivation practices were studied in Lanxi Water and Soil Conservation Supervision Station of Zhejiang Province. The results showed that compared with the traditional cultivation practice (treatment 5, straight farming), the other cultivation practices including grass strip, contour ditch, contour farming, contour dam, and fallow decreased soil nitrogen loss significantly, and the percentages of nitrogen loss under the 5 types of cultivation practices decreased by 43.46%, 46.55%, 71.36%, 77.05%, and 87.92%, respectively. Soil nitrogen lost mainly with runoff, and it accounted for 81.9-93.4% of total soil nitrogen loss. Dissolved nitrogen was the major form of lost nitrogen and accounted for 78-87.6% of total lost nitrogen in runoff. Nitrogen loss was occurred mainly during May to August, and it accounted for 85-100% of total annual nitrogen loss.