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In this paper, the large cross slope downslope tillage research object Zhongxian Deal Village Experiment Station of Soil and Water Conservation, Suining City, Sichuan solution Chichiawan Soil and Water Conservation Experiment Station runoff plot study unit, through soil erosion slope length, slope on the large cross slope downslope tillage soil erosion and nutrient loss observation and analysis, to explore. Slope length of the large cross slope downslope tillage mode test Zhongxian 10 ° runoff plots, divided into four treatments, T1-control treatment, full downslope planting, T2-on under 4m Longitudinal planting 4m cross slope cultivation T3-on under 5m downslope planting 3m cross slope cultivation, T4-on under 6m downslope planting 2m cross slope cultivation. Slope test the impact of the large cross slope downslope tillage mode in Suining 5 °, 10 °, 15 °, 20 ° slope runoff plots divided into four treatments, S1-5 ° cell on under 7m downslope planting 2m cross slope cultivation, S2-10 ° district on under 6m downslope cultivation 3m cross slope cultivation, S3-15 ° district on under 4.5m downslope planting 4.5m cross slope cultivation, S4-20 ° district on under 3m downslope planting 3m cross slope cultivation 3m downslope planted. Further promotion in the purple soil area to provide a theoretical basis for the large cross slope downslope tillage mode. The main conclusions are as follows: a large cross slope downslope tillage than downslope tillage can reduce runoff from 41.74% to 59.63%, which can effectively reduce runoff. Moderate rainfall, large cross slope downslope tillage mode shows a strong role in regulation runoff under heavy rainfall conditions, the weakening role of the large cross slope downslope tillage mode, cross slope a small downslope tillage mode with increasing downslope length, its water retention properties gradually reduced. 2. The Zhongxian trial point, runoff volume of the large cross slope downslope tillage and rainfall, rainfall duration was no correlation between the average rain at the 0.05 level very significantly associated with the average rain strong presents y = ax b (a gt; 0) positive linear correlation. Downslope tillage T1 runoff response than large cross slope downslope tillage (T2, T3, T4), under the same rainfall intensity, T2, T3, T4 mode downslope length shorter T2 mode response smallest, T3, T4 mode is not very different. Suining test points, large cross slope downslope tillage runoff and rainfall show a significant correlation. Each mode and the average rainfall intensity, rainfall duration were not related to the relationship. Runoff volume and rainfall presents each mode y = aln (x) b (a gt; 0) related to the number. 3 large cross slope downslope tillage compared to conventional downslope tillage showed better soil conservation performance under various rainfall conditions, especially in heavy rain conditions, soil conservation performance more significant. Moderate rainfall, the three \Gradually reduced, with the mode downslope length increases, soil conservation performance under conditions of heavy rainfall. 4 different slopes large cross slope downslope the tillage soil loss and rainfall lasted no obvious relationship exists with the runoff volume was significantly correlated. 5. S1 mode unit area of ??soil loss and rainfall significantly related to the remaining three slope (10 °, 15 °, 20 °) were significantly correlated rainfall. Average rain runoff relations, in addition to S1 mode, no significant correlation between the three remaining slope were significantly correlated highly significant correlation. Each mode previous rainfall, the highest concentration of potassium loss from the loss of nitrogen concentration in the runoff, followed by the lowest of the concentration of phosphorus losses in runoff. Simultaneously the highest proportion of runoff in the available potassium accounting for potassium and has been maintained at a high level, as high as 58.16% to 89.25%, the proportion of total nitrogen soluble nitrogen, followed by large amplitude changes in the range of 22.85% to 96.99% the lowest proportion of total phosphorus, soluble phosphorus and has been maintained at a low level, changes in the range of 6.40% to 22.67%. Large cross slope downslope tillage mode of nutrient per unit area of ??total losses were significantly less than downslope tillage mode. Phosphorus: Average rainfall conditions, T2 mode to reduce runoff loss of total phosphorus concentration effect best, T3 and T4 mode difference was not significant. Three cross slope downslope \Soluble phosphorus concentration differences between each mode, however, is not significant, the proportion of soluble total phosphorus by rainfall duration greater impact. Nitrogen: in heavy rain conditions, the mode of total nitrogen loss and lower concentrations than the downslope tillage mode in other rainfall conditions, large cross slope downslope tillage mode, can effectively reduce the total nitrogen runoff loss of concentration. Three cross slope down slope farming patterns, rainfall duration shorter, significant differences between the three modes, the best the shortest T2 mode effect downslope long, T3 followed, T4 mode The worst effect, the rainfall lasted longer case, there was no significant difference between the three modes. Concentration of each mode, the runoff total nitrogen loss by the double impact of the rainfall and cropping patterns. Loss of soluble nitrogen concentration in the runoff is mainly influenced by the rainfall, while the modes and effects are not significant. Potassium: previous rainfall in the runoff of each mode the concentration of potassium loss were higher, compared with the full downslope tillage T1 mode, large cross slope downslope tillage mode, T2 mode effect the best variety of rain under equally effective in reducing the loss of potassium, T3, T4 mode effect was not significantly different no obvious than hierarchical. The rainfall runoff total potassium, available potassium loss of concentration has a significant impact, significance probability 0.000, less than 0.01. Vulnerable to the loss of potassium in the soil, planting pattern on total potassium, available potassium loss of concentration has little effect. Each mode of sediment organic matter, total phosphorus, available phosphorus, available potassium has a certain degree of enrichment, enrichment trends more - cause. The effective potassium gt; the available phosphorus gt; full phosphorus gt; organic matter gt; total nitrogen gt; effective nitrogen gt; total potassium. The T1 mode sediment enrichment ratio of various nutrients in addition to organic matter enrichment ratio is lower than the other three modes, nutrient enrichment than than the other three modes, especially total phosphorus (1.45) and phosphorus (1.90 ) were significantly higher than the other three modes. Between the three modes, nutrient enrichment ratio was not significantly different. 7.T2, T3, T4 mode T1 mode compared to more significantly reduce the sand content of each slope position, the small amplitude increases the silt and clay content; comparison between T2, and T3, T4, mode, T2 The pattern of increasing and decreasing the amplitude ratio of T3, T4 mode, i.e. the T2 mode more significantly change the particle composition of the overburden soil. Each slope, large cross slope downslope tillage mode to maintain ability of topsoil potassium is not significant; each mode to keep the soil available phosphorus performed better in the S1, S2, S3, S4 mode poor performance; total nitrogen S1, S2 mode in terms of content, the total nitrogen content in the top of the hill, uphill located lower in downhill bit performance increase in the S3, S4 mode, the total nitrogen content in various slope positions showed reduced; total phosphorus, S1, S2, S3 mode in the top of the hill, uphill located reduced, a substantial increase in the slope position, has a small increase in the downhill bit, the foot of the slope, S4 mode of total phosphorus content in the top of the hill at the downhill bit lower in the substantial increase in uphill the bit and downhill bit at the foot of the slope at small amplitude increase. Surface soil organic matter and available nitrogen content of each mode, the changes are not large.
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