Influence of Different Straight Tillage & Contour Tillage Measures on Nitrogen Loss from Runoff and Runoff Loss

The effect of different straight tillage contour tillage measures in plot on nitrogen loss from runoff and runoff loss have been studied in Soil and Water Conservation Station in Zhongxian County,Chongqing.These results indicate that,compared with runoff under total straight tillage measure,runoff of 6 m straight tillage 2 m contour tillage,5 m straight tillage 3 m contour tillage,4 m straight tillage 4 m contour tillage reduce 41.74%,45.84% and 59.63% respectively.There are no significant differences between four kinds of tillage measures on the total nitrogen loss during the duration of rainfall of 6.62 h-16.32 h.when less than 5.12 h,there are significant differences between 4 m straight tillage 4 m contour tillage and other tillage,and the best effect for 4 m straight tillage 4 m contour tillage.In the condition of duration of rainfall of 2.51 h and 3.22 h,there are significant differences between each other;The soluble nitrogen loss accounts for most of the nitrogen loss from runoff,and the proportion of soluble nitrogen loss accounts for total nitrogen loss is influenced by rainfall intensity and duration of rainfall.The loss of total nitrogen and soluble nitrogen per area of different straight tillage contour tillage measures are significant lower than that of total straight tillage measure.