Study On Dynamic Of Soil Moisture And Water-Soil Conservation For The Different Crops Land In Gaoquangou Valley Of Dingxi Region

By the long period case studied in the Losses Plateau demonstration district,combining with the crops data analysis, and chose six types typical crops, such as Triticum aestivum,Sesamum indicum,Pisum sativum Linn,Solanum tuberosu,Lablab purpureus were selected in Gaoquangou of DingXi of Gan sun in gully and hilly of Losses Plateau, site of the above changes in different levels of soil moisture for long-term fixed-point observation, set the cell was determined by the amount of runoff and erosion, and analysis of loess hilly and gully area of land in different years cycle of soil moisture, atmospheric precipitation distribution characteristics, soil erosion and Drive flow changes, as well as different types of land crops, soil and water conservation of soil moisture dynamics and effects, with a view to select the appropriate type of vegetation planted to improve water use efficiency, reduce soil erosion, provide the basis for. The results showed that:(1) From 1989 to 1995,the soil water of middle sunny slope in the small water shed of Gaoquan was: 1992<1989<1995<1991<1990<1994<1993, The variation coefficient was as the following: 1991年>1995>1994>1990>1989>1992>1993. And the coefficient of variation of the soil with different soil increased top-down showed a trend of decrease of soil moisture, surface is the most active area changes.(2) Soil water vertical variation tendency of sunny slope was basically identical and showed a tendency to reduce from top to bottom,The variation coefficients decrease with increasing soil depth;the soil water dynamic was can be divided into three stages:active layer(0～40cm),water intermediate layer,water stable layer ;Season dynamic can be divided into three stages:accumulating,consuming and stable.(3)Soil water content changes with precipitation in different year, the time of rainfall was similar,the soil water (1993 and 1994 ) of the different soil layer is higher than other Years. the soil water dynamic was influenced by rainfall,the highest level was September, the lowest level was May;In the crop growth processes of Prunus armeniaca, The precipitation consumption was used for evaporation, rising, Canopy interception.(4)The coefficient of years′surface runoff of all the different land use does not differ greatly, excluding a smaller runoff coefficient in potato land as23.17% , the other is basically the same, but less than the fallow which is 29.44%.(5)Runoff and erosion vary in Different year or different types of crops. The order of the average runoff of the multi-year in Different crop land use is as follows; Sesamum indicum > Fallow land > Pisum sativum > Lablab purpureus > Triticum aestivum >Solanum tuberosum; flax's runoff is largest but storage capacity is worst; potato's runoff is worst but storage capacity is largest. The order of the multi-year average erosion in different crop land use is as bellow : Fallow land > Sesamum indicum > Pisum sativum > Lablab purpureus > Triticum aestivum > Solanum tuberosum ; leisure land has the largest erosion but potato is in the minimum amount of erosion. capacity of water and soil conservation in Potato land is strongest, followed by wheat.