苏北花岗片麻岩地区USLE模型的试验研究

针对苏北花岗片麻岩地区水土流失的自然状况.建立了6种径流小区进行试验研究,通过对各小区364次降雨径流与土壤流失量的相关分析,得出适合本地区降雨侵蚀力因子R值的简便算式,确定了USLE模型中其它诸因子的取值.运用USLE模型计算各小区的土壤侵蚀量与实测值进行偏差分析,偏差为-3.5%～9.9%.可信度达90%以上.在实际应用检验中,梯田偏差5.64%,坡耕地偏差12.36%,可信度达87%以上.由此说明,USLE模型及其诸因子的取值方法在该地区的土壤侵蚀定量分析中具有很好的适用性.该项试验研究成果为该地区的水土流失预报与监测、水土保持规划及小流域综合治理提供了科学的依据.     

USLE在苏北花岗片麻岩区适用性研究

根据苏北花岗片麻岩区水土流失状况,布设6种处理的径流小区进行了9年试验观测,通过对364次降雨径流与泥沙流失量的相关分析,得出了适合本地区R值的简便算式和USLE中各因子的取值。采用USLE计算的土壤流失量与实测值比较,准确率达90%以上。本研究成果为该类地区水土流失预报与监测提供了科学简便的方法。     

川渝油气田建设水土流失影响因子分析

以川渝地区油气田管线建设区域为主要研究对象,确定了9条代表性输气管线工程,选取其中4条不同工程类型管线,现场设定24个典型监测点位,实地监测实际发生的水土流失量;利用通用方程USLE对水土流失量进行预测;运用SPSS软件对监测结果和预测结果进行拟合,同时对USLE中5个显著影响因子进行扰动性矩阵分析.结果表明:(1) USLE在川渝地区油气田建设过程中预测水土流失量与实际水土流失量的拟合效果较好,适用于研究区.(2)水土流失主要影响因子影响程度优先度排序为:土壤可蚀性因子＞植物覆盖因子＞降雨侵蚀因子＞土壤保持措施因子＞坡度因子.     

闽东南花岗岩地区土壤侵蚀的研究

本文系通过26个径流小区试验，经1985年～1987年3年的测试资料统计分析结果，阐明了在闽东南花岗岩地区的降雨参数在不同坡度，不同生物与工程相结合措施下对水土流失的影响，初步摸出本地区的水土流失规律，并提出生物措施是防治水土流失的最有效办法。为该地区进行有效治理提供了可靠的科学依据。     

岔路河特色农业经济开发区水土流失研究

应用修正过的通用土壤流失方程USLE，在遥感（RS）和地理信息系统（GIS）技术的支持下，确定了吉林省永吉县岔路河特色农业经济开发区的降雨因子、土壤侵蚀因子、坡度坡长因子和植被覆盖因子，估算了这一地区的水土流失模数。通过对这一地区各种土地利用类型进行水土流失分析，提出了保持该地区水土及促进该地区特色农业可持续发展的相应措施。     

径流曲线数法在黄土高原地表径流量计算中的应用

坡面径流是土壤侵蚀发生的基本动力 ,径流量计算是定量估算水土流失和进行水土保持效益评价的关键步骤。径流曲线数法是美国农业部开发的计算地表径流量的经验模型 ,它有使用简单、有效 ,且适用于资料匮乏地区等优点。介绍了径流曲线数法的基本原理和计算方法 ,并以陕西安塞 2 5个小区的降雨径流资料 (次降雨 )为基础 ,计算了黄土高原地区不同下垫面条件下的曲线数 (CN )值大小 ,并分析研究了 CN值和各影响因子间的关系 ,对该模型在黄土高原地区使用的有效性也进行了评定。     

小流域降雨因子与水土流失的相关性分析

依据晋西黄土丘陵沟壑区王家沟流域多年的实测降雨量、径流量、输沙量和侵蚀模数,选择了12个降雨因子,进行了降雨因子与水土流失的相关性分析。结果表明,不同降雨因子与水土流失的相关性迥异,不同治理时期降雨因子与水土流失的相关关系存在差异;基于降雨因子与水土流失的关系所拟合的曲线模型多为二次方程与S曲线形;流域治理后期(1971年以后),随着治理面积的逐年增加,综合治理程度的提高,明显改善了降雨、径流和输沙的关系,降雨因子对流域水土流失的影响进一步减弱。     

南方红壤区植被覆盖因子估算模型构建与验证

研究红壤区植被覆盖因子变化规律、构建植被覆盖因子计算模型可为该区域水土流失防治及动态监测提供科学依据。该研究基于广东省五华县水土保持试验推广站200余场降雨试验观测数据,分析了影响水土流失的各关键因子与次降雨土壤侵蚀模数(Individual Rainfall Event Soil Erosion Modulus,ISEM)间定量关系,基于中国土壤流失方程计算了系列次降雨事件不同植被覆盖度对应植被覆盖因子值,构建了植被覆盖因子值与植被覆盖度间数学模型,从点、面2个尺度对模型计算精度进行了验证。结果表明:1)ISEM随植被覆盖度增加而降低;ISEM与雨前土壤表层含水率间存在显著正相关对数关系;ISEM随坡度增加呈先增后减的变化规律;ISEM随次降雨量、次降雨侵蚀力和次降雨径流深呈显著正相关线性变化关系。2)构建了植被覆盖因子值与植被覆盖度间二阶指数衰减模型,该模型决定系数和纳什系数分别达0.947和0.876。点尺度验证结果表明90%样本模型计算值与观测值相对误差均小于0.30;面尺度验证结果表明,70%～80%的植被覆盖因子计算值相对误差不超过0.1。总体而言,该模型计算精度较为理想,但由于研究对象典型的时空尺度特征,仍需要更多观测数据对该模型进行完善和验证。研究成果可为深入理解红壤区土壤侵蚀规律、水土流失动态监测提供有益参考。     

红壤丘陵区典型区域湖南长沙市非点源污染量化研究

结合通用土壤流失方程(USLE)和USEPA开发的PLOAD方程,建立非点源污染计算模型,采用GIS技术及野外实验确定模型中各个因子,并将该模型用于长沙市的非点源氮、磷污染负荷的计算。研究结果表明:长沙市地区非点源氮、磷污染负荷分别为9.9kghm-2a-1,1.49kghm-2a-1,其中氮污染主要以溶解态氮的形式存在,与降雨过程中产生的地表径流密切相关;污染来源最大的区域是城市用地区域,该区域的下垫面不透水率大,降雨过程中产生地表径流大;磷污染主要以吸附态磷的形式存在,来源较大的区域主要为坡度大、易发生水土流失的区域。     

粤西坡耕地区水土流失特征及防治措施——以泗纶小流域为例

选取广东省泗纶小流域为研究区,以GIS技术为支撑,选用通用土壤流失方程(USLE)为数学模型,利用GIS技术的空间分析功能,计算降雨、植被、土壤、地形、土地利用等单因子并叠加分析,生成水土流失现状分布图。通过对区域内的土壤侵蚀强度进行分析、评价,得出影响流域水土流失的关键因子,并根据研究结果对流域内坡耕地水土流失提出相关防治措施,从而为广东省坡耕地区小流域水土流失治理提供理论支撑。     

Applying the USLE Family of Models at the Sparacia (South Italy) Experimental Site

Soil erosion is a key process to understand the land degradation, and modelling of soil erosion will help to understand the process and to foresee its impacts. The applicability of the Universal Soil Loss Equation (USLE) at event scale is affected by the fact that USLE rainfall erosivity factor does not take into account runoff explicitly. USLE‐M and USLE‐MM, including the effect of runoff in the event rainfall–runoff erosivity factor, are characterized by a better capacity to predict event soil loss. The specific objectives of this paper were (i) to determine the suitable parameterization of USLE, USLE‐M and USLE‐MM by using the dataseries of Sparacia experimental site and (ii) to evaluate their performances at both event and annual scale. The measurements allowed to establish the relationships for calculating the factors of USLE, USLE‐M and USLE‐MM usable at the Sparacia experimental area. At first, for slope‐length values greater than 33 m, the calibration of USLE model at event scale pointed out that sediment delivery processes, that is processes involving deposition of the transported eroded soil particles, occur. The analysis showed that USLE and USLE‐M tend to overestimate low event soil losses, while for USLE‐MM, this tendency is less pronounced. However, the USLE‐MM performed better than USLE and USLE‐M and was able to reproduce better than other two models the highest soil loss values that are the most interesting from a practical point of view. The results obtained at annual scale were generally consistent with those obtained at event scale. Copyright © 2016 John Wiley & Sons, Ltd.     

Erodibility of agricultural soils on the Loess Plateau of China

Soil erodibility is thought of as the ease with which soil is detached by splash during rainfall or by surface flow. Soil erodibility is an important factor in determining the rate of soil loss. In the universal soil loss equation (USLE) and the revised universal soil loss equation (RUSLE), soil erodibility is represented by an erodibility factor (K). The K factor was defined as the mean rate of soil loss per unit rainfall erosivity index from unit runoff plots. Although high rate of soil loss from the Loess Plateau in China is well known and widely documented, it is remarkable that there is little systematic attempt to develop and validate an erodibility index for soils on the Loess Plateu for erosion prediction. Field experimental data from four sites on the Loess Plateau were analyzed to determine the K factor for USLE/RUSLE and to compare with another erodibility index based on soil loss and runoff commonly used for the region. The data set consists of event erosivity index, runoff, and soil loss for 17 runoff plots with slope ranging from 8.7 to 60.1%. Results indicate that the K factor for USLE/RULSE is more appropriate for agricultural soils on the Loess Plateau than the erodibility index developed locally. Values of the K factor for loessial soils range from 0.0096 to 0.0269 t h/(MJ mm). The spatial distribution of the K value in the study area follows a simple pattern showing high values in areas with low clay content. For the four sites investigated, the K factor was significantly related to the clay content, (K=0.031−0.0013 Cl, r²=0.75), where Cl is the clay content in percent. The measured values of the K factor are systematically lower than the nomograph-based estimates by a factor of 3.3–8.4. This implies that use of the nomograph method to estimate soil erodibility would considerably over-predict the rate of soil loss, and local relationship between soil property and the K factor is required for soil erosion prediction for the region.     

北京市土壤侵蚀监测方法探讨

 为了科学定量评价北京市土壤侵蚀状况,通过北京市地面水土流失监测网络,开展水土流失定点观测,研究北京市土壤侵蚀监测的评价方法。结果表明：利用大量实测资料,基于美国通用土壤流失方程建立的北京土壤流失方程,可以作为北京市土壤侵蚀调查的模型工具;基T GIS和降雨侵蚀力模型的年度土壤侵蚀量推算方法,可作为从小区尺度转换到区域尺度的一种方法;由于网格法没有考虑水土保持措施因子,调查得到的土壤侵蚀量结果比采用抽样调查法得到的结果偏大。北京市土壤侵蚀监测方法的研究可为区域水土流失定量评价和动态监测提供借鉴作用。     

Modelling runoff and soil erosion in logged forests: Scope and application of some existing models

Predictive erosion models are useful tools for evaluating the impact of land-use practices on soil and water properties, and as often used by environmental protection authorities, for setting guidelines and standards for regulation purposes. This study examines the application of three erosion models of varying complexity and design for predicting runoff and soil erosion from logged forest compartments in south eastern Australia. These are: the Universal Soil Loss Equation (USLE), the Water Erosion Prediction Project (WEPP), and TOPOG, a physically based hydrologic modelling package. Data on rates of soil loss and redistribution collected during a series of large-scale rainfall simulator experiments were used as model input parameters and validation. The models were evaluated in terms of general ease of use, input data requirements and accuracy of process understanding and prediction. Results suggest that in this application the USLE overestimated soil loss, and have the limitation that it does not predict sediment yield or sediment redistribution for specific storm events. When used at the hillslope scale, WEPP and TOPOG have predicted runoff and soil loss reasonably well, particularly on disturbed surfaces such as skid trails. On less disturbed surfaces such as the general harvesting area, both models performed less accurately, generally under-predicting soil loss and sediment yield, notably on sites with low observed values. The complexity and data requirements of WEPP and TOPOG limit their usability as a general-purpose, erosion hazard predicting tool. In terms of process understanding, none of the existing models accurately depict the nature and extent of sediment redistribution quantified in the rainfall simulator experiments. In order to advance the application and accuracy of modelling tools in forestry environments, this redistribution process should be considered integral to the refinement and redevelopment of future models.     

福建省长汀县不同土地利用方式下的坡地侵蚀特征

根据福建省长汀县径流小区2014-2018年的实测资料，对不同土地利用方式下的坡地侵蚀特征进行研究，分析各径流小区土壤流失量、径流量与降雨、水土保持措施、植被等因子的关系。结果表明：不同土地利用方式、不同水土保持措施的径流小区土壤流失量、径流量特征不同；年降雨量对各径流小区的年土壤流失量影响不显著，不同水土保持措施对径流小区的年土壤流失量影响显著；年降雨量和不同水土保持措施对各径流小区的年径流量影响均为显著；年土壤流失量和年径流量与年降雨量的相关系数均与水土保持措施及径流小区植物的种类和生长有关；各径流小区的年土壤流失量与年径流量均呈正相关，即年径流量越大，年土壤流失量越大。研究结果为长汀县水土流失治理提供参考。     

基于GIS的小流域养分流失预测

在GIS技术的支持下 ,将流域划分为多个独立的坡面单元 ,运用室内人工降雨实验坡面养分流失的研究结果和通用土壤流失方程 (USLE)进行了重庆市丰都三合小流域的养分流失预测与评价。研究结果表明 ,利用流域泥沙流失量进行流域养分流失预测时 ,只能对流域全量养分 (有机质、全氮、全磷、全钾 )的流失进行较为准确的预测 ,而对流域速效养分 (有效氮、有效磷、有效钾 )流失量进行预测时 ,径流携带流失的部分不能被忽略。要对流域养分流失量进行准确的预测与评价 ,必须通过建立流域分布式径流模型 ,结合土壤侵蚀模型来进行     

东北薄层黑土区作物轮作防治坡面侵蚀的效果与C值研究

作物轮作通过影响通用土壤流失方程(USLE)中作物覆盖和管理因子C值的变化和改良土壤性质而减少坡面土壤侵蚀。基于东北薄层黑土区连续6年大豆—红小豆轮作和裸露休闲坡面小区的径流泥沙和降雨资料,分析了2011—2016年研究区侵蚀性降雨特征,探讨了作物轮作防治坡面土壤侵蚀的效果,研究了作物轮作C值的年内和年际动态变化。结果表明:研究区所有侵蚀性降雨皆发生在5—10月,其降雨量占全年降水量的32.5%～68.1%,且年内和年际分布不均。对于5°坡度的裸露小区,土壤侵蚀主要发生在6—8月,坡面径流量和土壤流失量分别为48.4mm和1 388.2t/(km~2·a);对于5°坡度的作物轮作小区,土壤侵蚀主要发生在5—7月,坡面径流量和土壤流失量分别为19.5mm和166.7t/(km~2·a)。与裸露休闲小区相比,作物轮作小区可使黑土坡面年径流量和土壤流失量减少59.7%和88.0%。大豆—红小豆轮作措施的多年平均C值为0.12,其中大豆作物的C值为0.04,变化范围0.007～0.080;红小豆作物的C值为0.38,变化范围0.28～0.46。大豆和红小豆作物的C值月变化分别为0.01～0.24和0.01～0.80,呈先减少后增加的变化趋势。大豆—红小豆轮作对东北薄层黑土区坡面土壤侵蚀防治有明显效果,研究结果可为薄层黑土区土壤侵蚀定量评价和预报模型的建立提供基础数据。     

Converting USLE soil erodibilities for use with the QREI30 index

Changing the basis of the R factor in the Universal Soil Loss Equation (USLE) to one based on the Q_REI₃₀ index results in the need to calculate new soil erodibilities for use in the modified version (MUSLE-II). This paper provides a formula for calculating first approximations for the new soil erodibilities from known USLE soil erodibilities when data from runoff and soil loss plots associated with the determination of these USLE soil erodibilities are available.     

两种驱动力作用下植被调控堆积体坡面减水减沙效益

定量分析侵蚀驱动力的变化对于植被调控堆积体坡面水文和产沙过程的影响,对于深刻理解植被防护堆积体侵蚀及其水土保持效益具有重要作用。该研究以陡坡工程堆积体(30°)作为研究对象,采用野外模拟降雨和降雨+上方汇水试验研究苜蓿对工程堆积体侵蚀过程的影响及其减水减沙效益。结果表明:1)两种驱动力下苜蓿对工程堆积体坡面减沙和减流效益分别为57.28%～98.51%和13.17%～83.11%,加入上方汇水后减沙和减流效益分别减少17.01%和68.74%;2)降雨条件下苜蓿对堆积体坡面减流减沙效益随降雨强度增大降低,而加入上方汇水后减沙效益随降雨强度增大而增大,但减流效益减小。显著性差异分析表明降雨强度对裸坡和苜蓿堆积体的径流和产沙均有显著影响(P0.01),且上方汇水的作用大于降雨;3)两种驱动力下裸坡堆积体侵蚀速率总体随产流历时减少,而苜蓿堆积体在降雨条件下侵蚀速率总体增大。加入上方汇水后裸坡及苜蓿堆积体坡面侵蚀和径流随产流历时的波动性显著增强;4)裸坡堆积体在降雨和降雨+上方汇水条件下产流前期的平均侵蚀速率是后期的1.06～2.90倍,苜蓿堆积体在降雨条件下产流前期平均侵蚀速率小于后期。研究成果可为生产建设项目工程堆积体水土流失防治和植被措施布设提供科学指导,具有显著的科学意义和工程实践指导价值。