In current china,the research on comprehensive control of soil and water losses in small watershed using GIS is an important research direction in which soil erosion prediction provides significant foundation. Based o...
In current china,the research on comprehensive control of soil and water losses in small watershed using GIS is an important research direction in which soil erosion prediction provides significant foundation. Based on the softwares of ArcGIS 8.3 and Mapinfo 7.0 and combined with ecological principles,the objectives of this paper were to obtain erosion modulus by field rainfall experiments in various ecological terrain units,and to predict soil loss in the whole small *** to watershed water concentration principle, combinatorics principle,and weights analysis of environmental factors,which affect soil erosion of each ecological unit,we constructed the soil erosion prediction *** by performing rainfall simulation in Liudaogou small watershed,we simulated the *** following results were found:（1） Soil water erosion mainly occurs on the wasteland and Sparse Shrub and grassland with the slope of 15°5°,and is not whole small *** the slope sections of the severest soil water erosion,the soil erosion modulus are over 15000 t/kma。On the others slope sections,the soil erosion modulus are much smaller（2） Under the same situation,the greater rainfall intensity is,the greater erosion modulus is;（3）On sandy slope,once producing runoff,the sediment concentration would be large,and the formation process of gully is vertical seepage—slope undercurrent—landslip.（4） The soil erosion ecological prediction model can reflect the spatial difference of soil water erosion more *** it is more advantageous over RUSLE and WEEP in the Loess plateau with steep slope,small terrain plot and frequent rainstorm
With the support of remote sensing and GIS technology,the mean annual soil loss and the mean annual transport capacity in YiHe in 2000 were calculated by using WATEM/SEDEM model,and a soil erosion map was drawn accord...
With the support of remote sensing and GIS technology,the mean annual soil loss and the mean annual transport capacity in YiHe in 2000 were calculated by using WATEM/SEDEM model,and a soil erosion map was drawn according to the soil erosion intensity classification *** on these,the spatial distribution of water-and-soil loss and transport capacity in 2000 was *** analysis results of soil erosion situation show:the soil erosion area was 5184508 km in YiHe basin in 2000,42.49%in the total amount of soil erosion,and moderate levels of erosion above had revealed the degressive tendency in YiHe *** mean soil erosion modulus in this basin was 30.06 t·km·a,belonging to mild *** analysis results of sediment transport capacity show:the mean annual transport capacity was 12.92 t·km·a in YiHe basin and the transport capacity of unused was the strongest,54.4 t·km·a;different types of land use revealed sharply differences of sediment *** occurred mainly in tillage land and forest land,83.78%in the total amount of sediment *** may relate to,with the most in the mountainous watershed,the main land use types for the *** should strengthen effectively the management of land use types,adopting returning the grain plots to forestry and forest-grass to contain soil erosion within the basin in the future.
The unit current powers have some disorder in different water drainage,they undulate between 0.02 - 0.14m/s,0.05 - 0.35m/s,0.15 - 0.55m/s in different grades slope;on 20°￡lope,the unit current power waved steady...
The unit current powers have some disorder in different water drainage,they undulate between 0.02 - 0.14m/s,0.05 - 0.35m/s,0.15 - 0.55m/s in different grades slope;on 20°￡lope,the unit current power waved steady with time in 1,2 and 3L/min water drainage amount,the unit current powers decreased gradually first,and then got the waved steady in 4L/min water drainage amount,about 0.1 m/s;the unit current power was increasing -decreasing-waved steady in 5,7.5 and lOL/min water drainage amount;The unit current powers are increasing with slope grade increase except individual *** the initial stage,the unit current powers of 20°and 30°slope were closed,they increased firstly and then decreased,were bigger than 10°slope which was waved steady,the unit current powers of 20°and 30°slope got waved steady at 18min at 5L/min water drainage amount;they got the waved steady at 1 Omin,were 4 rimes of unit current powers on 10°slope at 7.5L/min water drainage amount.
The gully system is formed by two subsystems:intergully and *** intergully subsystem is composed by rill,shallow gully and small *** measuring and judging several periods' image of RS, merging the field investigat...
The gully system is formed by two subsystems:intergully and *** intergully subsystem is composed by rill,shallow gully and small *** measuring and judging several periods' image of RS, merging the field investigation and experiment,the results indicate that rill's distribution is the appearance of parallel or *** communicate angles are mostly 22.5°,the critical slope is 2°.when the critical slope is over 5°,the rill is most *** critical length of slope changes with the slope gradient between 11m and 110m,and with the slope gradient and the length of slope increase,the density of rill increases;The shallow gully are mostly on the slope over 5°or 8°,their appearance are mostly parallel branch;the communicate angle are mostly below 45°,and the critical length of slope are between 30m and 1200m and the small gully are mostly on the slope that are over 8°and near the boundary of *** minimum value is 43m and the maximum value is 5000m to the critical length of *** main factors influenced the development of shallow gully are the topography and the area of *** density is calculated by the formula p=-8.96+6.551og（jL） and the collecting water area is 0.289km2/km,its section area and the collecting water area are of the direct proportion to their relationship is the formula w=123.77+*** gully subsystem is composed by gully,scouring gully and *** relationship of the gully quantity（Nu）,the average length（Lu）,The average collecting water area（Au）,the average channel gradient（Ju） and the gully level（u） is expressed through following formulas:logNu=2.161-0.607u,logLu=0.437u-1.073,logAu=0.769u-1.626, logJu=*** the gully system,the velocity of development of the gully is the fastest and channe is the *** gully bed down-cutting and the gully head forward are averaged by 0.41m/a and 0.73m/a the scouring gully head forward is 0.35m/a,its bed downcutting of the is the fastest 3.73m/a the upper and middle re
Soil particle size is one of the key parameters determining splash erosion and soil crust *** on simulated rainfalls with a high intensity of 1.2 mm min-1,the rain splash erosion and soil crust development of Loess so...
Soil particle size is one of the key parameters determining splash erosion and soil crust *** on simulated rainfalls with a high intensity of 1.2 mm min-1,the rain splash erosion and soil crust development of Loess soil separates with different diameters are studied and the key factors predicting soil crust formation are *** results indicated that:(1) as the diameter of soil separates increases,the amount of detached particles increases from<0.038 mm to a maximum amount of 0.15-0.22 mm,and subsequently decreases;(2) the smaller the soil separates,the easier the development of soil crust and the higher the degree of soil crust development;(3) the susceptibility of soil crust formation can be predicted by integrating three indices of soil texture,aggregate stability,and rainfall energy together.
Soil erosion is a growing problem in the Yimeng Mountain area which is the representative area of the Rocky Area of Northern *** on three periods TM image data（Sep.1999,Sep.2003,Sep.2008） and will do some quantitati...
Soil erosion is a growing problem in the Yimeng Mountain area which is the representative area of the Rocky Area of Northern *** on three periods TM image data（Sep.1999,Sep.2003,Sep.2008） and will do some quantitative research on the dynamic soil erosion of Yimeng Mountain area in different periods using ERDAS 9.2,ArcGis 9.2 software and *** to the SL190-96 Standard,the intensity in this study area was divided into six degrees,i.e.,minimal,slight,moderate,intense,very intense and severe（Table 1）.The results shows that from the year of 1999 to 2008,soil erosion occurs mainly in minimal,slight,moderate and intense types,and the moderate erosion type was highest of all above the slight erosion *** the year of 1999 to 2003,the minimal degree soil erosion decreased by 423.74km, while the region which was above light degree erosion increased by 426.52km,which explains that the soil erosion of Yimeng mountain area shows the increasing tendency in five *** the year of 2003 to 2008, the minimal degree soil erosion increased by 559.08km,it mainly transformed by slight and moderate erosion type,which shows the decreasing tendency of the soil erosion intensity in Yimeng mountain area.
The strong altitudinal gradients leading to dramatic variations in environmental conditions in mountain regions provide unique and sometimes the best opportunities to study plant responses and adaptation to global cli...
The strong altitudinal gradients leading to dramatic variations in environmental conditions in mountain regions provide unique and sometimes the best opportunities to study plant responses and adaptation to global climate *** are the fastest growing woody plants in the *** growdi rate is highly dependent on local soil and climate *** understand the responses of dwarf bamboos to global climate change,we investigated the morphological characteristics and aboveground biomass allocation of Fargesia nitida along an elevational gradient ranging from its lowest distribution boundary（2450 m a.s.l.） to its uppermost distribution limit（3200 m） in Wolong Nature Reserve, southwestern *** structural（e.g.,clump density,clump area,ramet density per clump） and morphological（e.g.,leaf size,LMA,diameter,height,and biomass） responses of *** to elevation are not linear but form a one-humped,convex curve with a turning point at 850 m a.s.l.,as already shown in a previous study with *** carried out within the same elevational gradient on the same slope. These findings indicated that the fast-growing plants without secondary growth（***） respond to elevation similar with the slow-growing plants with secondary growth（***）.The non-linear responses may be mainly resulted from a precipitation-rich zone occurred at the intermediate elevation,and reflect the non-linear changes in environmental conditions along the elevational gradient,in spite of plant *** results also indicate the high sensitivity of *** to water availability under global climate change.
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