| Regional water scarcity in Yellow River Basin and conflicting between the upper andmiddle reaches and downstream of the Yellow River water is obviously. And downstreamsediment annually consumes more water. Soil and water conservation can reduce soil erosionon the slopes, and can reduce runoff generation as well in the same time; but the degree ofimpacts on erosion and runoff generation of different practices could be considered as newchance for watershed management very likely. Water cost for sediment control can affect themeasure effectively among different measures to reduce the amount of sediment on the degreeof runoff. The research was conducted in Loess plateau and took the bare slop as control. Thetypical basins in Loess plateau were analyzed, and then the characteristices of water cost forsediment control and the relations among various influence factors were discused. The mainresults were concluded as follows:Water cost for sediment control of single and comprehensive measures were compared.The results were:(1) Water costs for sediment control of single measures were different onslopes. That manifests tillage managements> terraces> planting grass> afforestation.(2)The average Rrsof the same individual practices were different in different regions and it hadlarge differences.(3) The Rrsof integrated measures were also different, the Third Sub-Regionof Hilly-Gullied Area of Loess Plateau is bigger than Frist and Sedond Sub-Region.The Rrsof typical individual measures were compred on slope of Loess plateau. Theresults were:(1) The Rrsof different tillage manifests contour tillage> ditch tillage> shallowplowing> deep plowing; For different crops, Rrsof intercropping of low-stem and high-stemcrops was larger than monoculture of low crops and rotation of middle high-stem crops.(2)For different forage management, Rrsof sweet clover rotation is25%bigger than that of thenatural grass slope. The Rrsof forage manifests drilling sweet clover> broadcasting alfalfa>sweet clover> alfalfa> natural grass slope. The Rrsof grass rotation manifests weetclover/crop> alfalfa/crop and it is bigger than that of forage rotation.(3) The Rrsof differentafforestation methods manifest common planting> fish-scale> level-terrace> level trench>pit planting. The Rrsof different vegetations manifests shrub> poplar forest (naturaldeciduous broadleaved forest)> Chinese pine forest (evergreen coniferous forest). For different land use types, Rrsof agro-forestry is27%bigger than that of afforestation inwasteland.The relationships between individual measures and various influence factors wereanalyzed in typical regions. The results were: the Rrsof slope terrace and forest and grassmeasures and precipitation, soil erosion modulus inverse exponential correlations. The Rrsofslope terrace, forest and grass measures and I30showed a good inversely linear relationship.When I30was more than0.29mm/min and0.48mm/min respectively, Rrsand slope showeda good exponential relationship. The Rrsof tillage measures increased when the precipitationdecreasing.Through the allocation of different soil and water conservation measures, slope runoffand quantity of sediment can be regulated. The measures whose Rrsis bigger is beneficial toincrease soil moisture when reducing the same amount of sediment, but is not conducive tothe formation of runoff. If the soil and water conservation measures with smaller Rrsareselected, it can increase runoff when reducing Yellow River sediment, its impact on runoffand river water resources is small, and it will be more beneficial to the redistribution of waterrescources in the basin interior, it can provide more scientific basis for the Yellow RiverBasin’s more rational planning. |
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