水保所知识产出(1956---)知识库

土壤本身的抗侵蚀性反映了土壤对侵蚀的敏感程度，是影响区域水蚀土壤流失量的内因。因此，对区域尺度土壤侵蚀机理进行深入研究，对于我国建立区域尺度土壤侵蚀预报模型以及进行大规模水土保持生态环境效应评价等都具有重要的理论意义和实践意义。基于此，本研究以土壤侵蚀力学、土壤物理学、水动力学等为基础，以我国最具代表性的侵蚀性土壤为研究对象，通过人工模拟试验分析侵蚀过程的特征和机理，力图建立一个土壤侵蚀学意义明确、带量纲单位且与侵蚀动力因子量纲单位相匹配的能反映土壤抗侵蚀综合性能的指标，并将这一关系式推广到区域尺度上，为区域水土流失预测模型提供依据。
论文主要研究结果与结论如下：
⑴ 基于能耗理论的土壤抗侵蚀性指标的建立
利用能量守恒定律分析了水流自坡面顶端到坡面上任一断面间的能量损耗，得出所观测土壤在试验坡度范围内，径流能耗越大，径流侵蚀产沙率越大；在径流能耗一定的情况下，径流侵蚀产沙率随坡度的增大而增大。以径流能耗原理为基础，提出土壤抗侵蚀指数（KＥ，g/J·cm-2·min-1）的概念。引入曲线平均斜率确立了土壤抗侵蚀指标均值EK的表达式，EK值越大，土壤抗侵蚀能力愈弱。四种土壤EK大小关系为：黑土（0.081）> 黄绵土（0.062）> 紫色土（0.047 ）> 红壤（0.0245）。
⑵ 土壤抗侵蚀指数与土壤可蚀性K间的关系
四种土壤次降雨条件下土壤可蚀性K值（美国制）存在较大差异。坡面侵蚀量与降雨侵蚀力坡度、坡长因子之间存在良好的线性相关关系，四种土壤进行多次模拟降雨过程综合计算后的K值分别为 0.0214 （红壤）、0.0265（紫色土）、0.0546（黑土）、0.0784（黄土），并比较了抗侵蚀指数与可蚀性K值的关系，得出两者之间主要呈现线性相关关系。
⑶ 土壤抗侵蚀指数与抗冲系数之间的关系
不同母质发育土壤抗冲系数差异明显，主要与>0.25 mm水稳性团粒以及土壤粘粒含量等理化属性有关。土壤抗冲性随土壤类型变化由大至小依次为红壤>紫色土>黄土>黑土。土壤抗侵蚀指数KE随着抗冲系数Kc增大而减小，二者呈现良好的乘幂关系，得到了抗侵蚀指数的简易测试和计算方法。
⑷ 土壤抗侵蚀指数与土壤可蚀性估算值之间的关系
不同模型下四种土壤的估算K值有较大差异。四种模型估算的土壤可蚀性值与抗侵蚀指数KE值之间存在较好的线性关系，并在此基础上提出了我国不同地区及不同资料情况下的土壤抗侵蚀指数的估算方法。
⑸ 土壤抗侵蚀指数在坡面上的验证
降雨条件下四种土壤坡面土壤侵蚀量的实测值大于计算值，究其原因是由于降雨溅蚀使得坡面径流搬运相同数量的土体所需的能耗减小造成的。计算值与实测值之间呈显著的正相关，二者之间相关性较好。
⑹ 土壤抗侵蚀指数的应用
将抗侵蚀指数输入区域水土流失模型模拟延河流域侵蚀产沙量，模拟得到1995年7月份延河流域出口输沙量为0.20亿t。根据中华人民共和国水利部2000年发布的《中国河流泥沙公报》显示：延河流域甘谷驿站多年平均输沙量为0.4656亿t，证明了抗侵蚀指数应用在较大区域上的可行性。
关键词：土壤抗侵蚀指数；人工模拟试验；抗冲性；可蚀性K值；区域土壤侵蚀模型；能耗理论

Soil as the erosion object, its anti-erosion capability reflects the sensitivity degree of soil to erosion and is the inherent factor influencing the process of soil erosion．So researching on the soil erosion mechanism and regulation of regional scale has important significance for building soil erosion prediction model of regional scale and massive work of soil and water conservation and environment construction. Based on involved scientific theory of soil erosion science, soil physics, and hydrodynamics, this research analyzed the character and mechanism of soil erosion progress of four typical soil types through artificial simulation experiments. The objective of our research is to build a comprehensive index which can reflect soil anti-erosion capability, and apply it to the regional soil erosion resrarch. Main results are as follows:
1. Proposition of soil anti-erosion index based on energy consumption theory.
The relationship between the soil detachment and the runoff energy consumption is studied by using the law of conservation energy in this part. The soil erosion rate increases as runoff energy consumption increases, and it also tends to increase with increasing slope gradient under same runoff energy consumption. The soil erosion rate model is built, and a new erosion critical index is put forward. Based on the energy consumption theory of run-off, the concept of soil anti-erosion index (KE, g/J·cm-2·min-1) is proposed. And the expression of mean erosion index value is also built according to mean curve slope. The mean anti-erosion index values of four soils are black soil (0.081) >loess soil (0.062) > purple soil (0.047) > red soil (0.0245).
2. The relationship between soil anti-erosion index and soil erodibility
Under simulated rainfall conditions, soil erodibility K values are diverse, which shows that error will exist when soil erodibility (K-factor) is directly applied to the soil erosion calculation under single rainfall event. Slope erosion quantity showes a linear correlation with rainfall erosivity, slope gradient and slope length. Combined the course of simulated rainfall on many occasions, the K values of red soil, purple soil, black soil and  loess soil are 0.0214, 0.0265, 0.0546 and 0.0784, respectively. And the relationship between soil anti-erosion index and soil erodibility is described quantitatively.
3. The relationship between soil anti-erosion index and soil anti-scourability coefficient.
Soil anti-scourability coefficients are evidently different from different parent material, which is due to difference of >0.25 mm water-stable aggregates and soil clay content. Soil anti-scourability ability is red soil > purple soil > loess soil > black soil. Soil anti-erosion index decreases as soil anti-scourability coefficient increases under different slope gradients and flows, and the both show a fine correlation of power.
4. The relationship between soil anti-erosion index and simulated erodibility K values
Simulated erodibility K values of four soil types show a great difference under different models, and simulated K values are generally bigger than that of soil anti-erosion index. There is a fine linear correlation between simulated K values and soil anti-erosion index. A new method is advanced for estimating soil anti-erosion index of the soils in China despite of difference in geographic region and availability of data.
5. The test of soil anti-erosion index on the slope
The observed values of soil erosion quantity is generally bigger than that of simulated values. However, further analysis indicates the significantly positive correlation between the observed values and the simulated values, which shows a line correlation. Coefficients of determination of the observed values and the simulated values reveal the rationality of soil anti-erosion index on the slope.
6. Application of soil anti-erosion index
The erosion index is primarily applied to simulate the sediment yield in July, 1995 during a case study in Yanhe River basin. The results indicate that the simulated sediment  amounts are 20 million tons. The simulated results in Yanhe River basin prove that soil anti-erosion index is feasible on the regional scale.
Key Words: soil anti-erosion index; artificial simulation experiments; anti-scourability; erodibility K value; regional soil erosion model；energy consumption theory