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| 1 | 确定侵蚀细沟集中水流剥离速率的解析方法显示文摘细沟中的泥沙主要来源于细沟流对土壤的剥蚀作用 ,细沟剥蚀作用的大小由剥蚀率来表述。剥蚀率是侵蚀过程预报模型的重要物理参数 ,本文创造性提出了一种确定侵蚀细沟集中水流剥离速率的解析方法。该方法用细沟侵蚀模拟试验所确定的沟长与水流载沙量的函数关系 ,以及相应的回归参数 ,通过将函数对距离求导数 ,得到了水流的剥离速率与细沟长度的函数关系。由此 ,进一步确定了剥离速率与水流载沙量的函数关系。将由解析法得到的剥离速率与由试验数据直接计算得到的结果进行了对比 ,得到不同坡度的确定系数下R2 值最小为 0 .65(坡度为 5) ,n=1 6 ,最好的拟合R2 值 0 .96(坡度为 2 0°) ,n =2 4 ,证明了该解析方法的可行性。 | 雷廷武 张晴雯 赵军 Mark A.Nearing | 2002 | 土壤学报2002，39，6： | 14 |
| 2 | Assessing phenological change in China from 1982 to 2006 using AVHRR imagery显示文摘在植被物候学的长期的趋势由于人的活动和气候的联合影响显示生态系统变化。在我们使用了的这研究, 1982 ~ 2006 先进很高的分辨率辐射计使差别植被索引(AVHRR NDVI ) 正常化越过中国和 TIMESAT 程序的形象确定年度植被生产和它的变化趋势。结果在 25 年的学习时期期间在国内在植被生长和它的时间的趋势显示出大空间可变性。在植被生产的重要减少在内部蒙古的草地,并且在使工业化被检测在南部的中国的区域包括珍珠河三角洲,沿着长江的长江三角洲,和区域。植被生产的重要增加在 Xinjiang,华中,和东北方中国被发现。NDVI 趋势和生长区域变化的确认用 Landsat 形象被进行,结果与从 AVHRR 数据的分析一致。我们也发现尽管植被变化的原因局部地变化,植被变化的空间模式和从国家政策的最大的影响的区域在1970年代发射了,例如经济地区和“三北方的躲蔽处福雷斯特计划”的开始,是类似的,它显示在生态系统变化和那上的国家政策的影响如此的影响能用在这份报纸描述的方法被检测[出版摘要] | Haiyan WEI Philip HEILMAN Jiaguo QI Mark A.NEARING Zhihui GU Yongguang ZHANG | 2012 | Frontiers of Earth Science2012，6，3： | 10 |
| 3 | Natural and anthropogenic rates of soil erosion显示文摘Regions of land that are brought into crop production from native vegetation typically undergo a period of soil erosion instability,and long term erosion rates are greater than for natural lands as long as the land continues being used for crop production.Average rates of soil erosion under natural,non-cropped conditions have been documented to be less than 2 Mg ha^(-1) yr^(-1).On-site rates of erosion of lands under cultivation over large cropland areas,such as in the United States,have been documented to be on the order of6 Mg ha^(-1) yr^(-1)or more.In northeastern China,lands that were brought into production during the last century are thought to have average rates of erosion over this large area of as much as 15 Mg ha^(-1) yr^(-1) or more.Broadly applied soil conservation practices,and in particular conservation tillage and no-till cropping,have been found to be effective in reducing rates of erosion,as was seen in the United States when the average rates of erosion on cropped lands decreased from on the order of 9Mg ha^(-1) yr^(-1) to 6 or 7Mg ha^(-1) yr^(-1) between 1982 and 2002,coincident with the widespread adoption of new conservation tillage and residue management practices.Taking cropped lands out of production and restoring them to perennial plant cover,as was done in areas of the United States under the Conservation Reserve Program,is thought to reduce average erosion rates to approximately 1 Mg ha^(-1) yr^(-1) or less on those lands. | Mark A.Nearing Yun Xie Baoyuan Liu Yu Ye | 2017 | International Soil and Water Conservation Research2017，5，2： | 3 |
| 4 | Rangeland hillslope lengths:A case study at the Walnut Gulch Experimental Watershed,southeastern Arizona显示文摘Rangeland hillslopes provide much of the sediment supplied to channel systems and their lengths exert a fundamental constraint on hillslope diffusive processes.However,information regarding lengths of rangeland hillslopes,and how best to estimate them,is limited.In this study,three groups of watersheds(10 in total)were selected from the Walnut Gulch Experimental Watershed according to their geology,soil and vegetation characteristics.Group 1 watersheds were at lower elevations dominated by shrubs,Group 3 were at high elevations dominated by grass,and Group 2 were mixed shrub and grass.Their hillslope lengths were calculated from 1 m-resolution DEMs using three methods:a flow routing algorithm,slope-area relationships,and inverted relationship with drainage density.Parameters that characterize the current watersheds,including Hack's exponent and coefficient,watershed shape coefficient,channel concavity and steepness,and surface roughness,were quantified and related to hillslope lengths.Results shows:(1)estimated hillslope lengths were different for the three methods and between the three groups of watersheds;(2)hillslope lengths that measured from the flow routing algorithm for the ten selected watersheds primarily ranged from 30 to 100 m,with a median value of 63.0 m,which was 20%e50%greater than those derived from slope-area plots or drainage densities;(3)hillslope lengths estimated from the flow routing method were greater in Group 3 watersheds than in Group 2 and then in Group 1 watersheds.We attributed these differences in hillslope lengths to the historic epeirogenic pulses,watershed and drainage network morphology,and differences in vegetation characteristics;(4)measured hillslope lengths from the flow routing algorithm were best correlated with hillslope relief,then surface roughness,channel steepness and concavity.These results would benefit the applications of hydrological and erosion models in rangelands. | Li Li Mark A.Nearing Philip Heilman Mary H.Nichols D.P.Guertin C.J.Williams | 2022 | International Soil and Water Conservation Research2022，10，4： | 1 |
| 5 | An updated isoerodent map of the conterminous United States显示文摘Maps of erosivity,which are also commonly referred to as isoerodent maps,have played a critical role in soil conservation efforts in the United States and around the world.Currently available erosivity maps for the United States are either outdated,conflict with erosivity benchmarking studies,or utilized less advanced spatial mapping methods.Furthermore,it is possible that the same underlying issues with US maps are impacting global maps as well.In this study,we used more than 340015-min,fixed-interval precipitation gauges to update the isoerodent map of the conterminous United States.Erosivity values were interpolated using universal kriging under several spatial model configurations and resolutions.The optimal spatial model was selected based on which result had the lowest sample variogram error.Rainfall,erosivity,and erosivity density maps were compared to existing products.Some average annual and annual erosivity results were compared to high-quality erosivity benchmarking publications.Erosivity values from both RUSLE2 and Panagos et al.(2017)were generally lower in the eastern United States and mixed in the western United States compared to our results.Topographic effects resulted in much greater erosivity differences in this study as compared to prior maps.Benchmark comparisons revealed that erosivity maps from this study and others were lower than the benchmark by 14%or more(up to 38%).These findings suggest current practices of storm omission and intensity dampening correction need to be revisited,especially in locations with relatively low-to-moderate rainfall erosivity such as the Midwest or Northeast United States,for example. | Ryan P.McGehee Dennis C.Flanagan Puneet Srivastava Bernard A.Engel Chi-Hua Huang Mark A.Nearing | 2022 | International Soil and Water Conservation Research2022，10，1： | 0 |
| 6 | Modeling hydrologic responses using multi-site and single-site rainfall generators in a semi-arid watershed显示文摘Hydrologic response in a watershed is driven by precipitation.Multi-site rainfall generators can be used to model watersheds using spatially varied rainfall inputs to better analyze how the rainfall variability affects runoff generation.This study adopted both a single-site rainfall generator(CLIGEN)and a multi-site rainfall generator to generate two rainfall data sequences,which were then used to drive the Soil and Water Assessment Tool(SWAT)for runoff simulation.The 148-km2 Walnut Gulch Experimental Watershed and its two sub-watersheds were selected to evaluate the hydrologic response.Runoff calibration was done against measured runoff in the watershed.Statistics showed that the single-site and multi-site rainfall generators gave similar results regarding annual precipitation.However,the multi-site generator performed much better than the single-site generator in both mean summer flow and for the different return period flows.The runoff derived from the single-site generator was significantly over-estimated in all three watersheds.As for the multi-site generator,the derived runoff was satisfactorily predicted in the smaller watersheds but only overestimated in the largest watershed.This indicated that in small to medium sized watersheds,the spatial variability of rainfall could play an important role for hydrologic response because of the heterogeneity of convective rainfall in this semi-arid region,which makes the application of multi-site rainfall generator a better option than the single-site generator. | Ying Zhao Mark A.Nearing David Phillip Guertin | 2022 | International Soil and Water Conservation Research2022，10，2： | 0 |
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