| The research on climate and paleosol of the Loess Plateau has made great achievements, but the impact of environmental change about hydrological properties and enrichment conditions of groundwater of loess has not been studied.There are little research about deep infiltration and water conditions of loess stratum, but the research is very important. The research not only has important scientific significance for understanding the enrichment conditions and rules about groundwater and aquifer in Loess Plateau, but also has important practical significance about development and utilization of loess water resources. Meanwhile it has important significance on revealing movement and enrichment deposit types of aquifer and groundwater of loess stratum.According to the field research and experiment at Xigou in Fengqi of Luochuan, we analyzed the infiltration rules of loess and paleosol. We also determined and analyzed soil samples about granularity, porosity, magnetic susceptibility and content of CaCO3. By investigating their connection, we obtained the following conclusions:(1) The average of stability infiltration rates of the loess layers at Fengqi profile in Luochuan is 0.67mm/min, and which of the paleosol layers is 0.29mm / min. The stability infiltration rate of the 15th loess layers(L15) is the largest, which is about 1.10mm/min. The stability infiltration rate of the 10th paleosols(S10) is the lowest, which is about 0.08mm/min. Usually, it takes 80-100 minutes to stabilize the infiltration rate at Fengqi profile(L9-S15) in Luochuan.(2) By the seeping experiment datas non-linear fitting with three kinds of experience model, we can get the best fitting results with experience formula and Koctakob formula, which can be applied to describe soil infiltration of loess layers and paleosol layers at Fengqi in Luochuan. The average and standard deviation for every parameter of two experience formula can provide important reference for hydrological and agricultural sector using the seeping experience formula.(3) The characteristic infiltration of the loess layers and paleosol layers is controlled by the climate and pedogenesis of that time. Although L9-L15 layers is affected by the soil gravity which more than 50m thick overlying, the basic infiltration characteristic that the loess layer permeability is greater than the paleosol layer is not changed.(4) Porosity, colloid content and infiltration rate have a greater relationship in profile we studied. The porosity of loess layer generally greater than the paleosol layer. The colloid content of loess layer is generally less than the paleosol layer. The paleosol layer is easy to form a waterproof layer because of poor permeability. The larger Infiltration rate and more water spaces of loess layer enable the formation of the aquifer.(5) The magnetic susceptibility has significant negative correlation with content of CaCO3 and significant positive correlation with colloid content, In the dryer and colder climate conditions, the loess layer grows with weak pedogenesis. In the warmer and wetter climate conditions, the paleosol layer grows with strong pedogenesis and abundant rainfall. The content of CaCO3 strongly affected by leaching. The climatic difference is power factor, which determined the different hydrological characteristics in these layers.(6) According to the different strength of pedogenesis, we can identify enrichment rules and groundwater layers. The strong pedogenesis and weak permeability of paleosol layer and the loess layers which has weak pedogenesis and better water space is a good combination of aquifer. The weak pedogenesis and larger permeability of paleosol layer and the loess layers which has thin thickness and strong weathering action is a bad combination of aquifer, which is not conducive to the enrichment of groundwater. A good combination of aquifer is from the 9th loess layer to the 10th paleosol layer. Another good combination of aquifer probably is from the 15th loess layer to the 15th paleosol layer. |
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