横坡垄作细沟形态特征及其影响因素

摘要

Because of possessing the advantages of capturing water sources ,reducing surface runoff and maintaining soil fertility ,the cross ridging system has been widely used in slope cropland.As there are difficulties in precisely keeping the contours during the actual operation process ,it leads to the existence of ridge grade and makes it easy to accumulate plentiful rain falls in furrows which can induce ridge collapse and rill erosion.This article focuses on the analysis of the influencing factors of rill morphology and the morphological features based on the artificial rainfall simulation experiments and 3D scan technology.The results show that the increase of the ridge's height can expand the maximum rill width and depth;the influence of seepage on the maximum rill depth is expressed as a quadratic function.When the maximum rill depth reaches above 14.3cm ,seepage has a positive effect on it ,but when the maximum rill depth is below 14.3cm ,seepage has a negative effect on it.Meanwhile ,seepage presents a positive effect on the maximum rill depth.The relationship between the total sediment yield and seepage also presents as quadratic function.The increase rate of the maximum rill width is 1.7 times of the maximum rill depth.On the basis of the simplified rill volume prediction L - V model ( V = aLb ) , the article proposes the simplified rill volume prediction model ( V= a*(D* L)b ) by incorporating the maximum rill depth under the condition of ridge culture on cross slope ,and the R2 of the model increases from 0.61 to 0.92.Therefore ,the model can increase the prediction accuracy obviously.%指出了横坡垄作具有涵养水源 ,减少地表径流与土壤肥力流失的优点 ,已被广泛应用于坡耕地.由于具体实施中难以精确等高控制 ,导致垄向坡度的存在 ,在垄沟内聚集大量雨水引起横垄垮塌 ,造成细沟侵蚀.利用人工模拟降雨实验及三维立体扫描技术对细沟形态的影响因素及其形态特征进行了分析 ,结果发现 :增加垄高能够明显增加细沟最大沟宽与最大沟深 ;渗流对最大细沟宽度的影响呈二次函数 ,当细沟最大宽度大于14 .3cm时 ,渗流与细沟最大宽度有正影响 ,当细沟最大宽度低于此值时 ,为负影响 ;渗流对细沟最大深度为正影响 ;总产沙量与渗流的关系也呈二次函数 ;细沟最大宽度的增加速率是细沟最大深度的1 .7倍 ;在已有的细沟体积预测模型L-V模型(V= aLb )的基础上 ,纳入细沟最大深度提出了横坡垄作条件下的简便细沟体积预测模型(V= a*(D*L)b) ,R2 从0.61提高到0.92 ,模型预测精度显著提高.