Expermental Studies On Effects PAM Conditioning And Prewetting On Infiltration And Eosion

Arid, semi-arid regions have the problem that soil surface breadcrust hardens. After soil surface breadcrust, it caused that reduced soil infiltration rate, increased runoff and erosion. The reasons of soil surface crust are made up of the internal and external reasons of the two parts. The internal conditions include that soil structure, organic matter content, soil chemical properties and so on. The external conditions include that water quality, soil aggregate stability, etc. Affect the stability of soil aggregates of factors include that the sub speed, soil moisture and aging time. The pace of moist soil aggregate stability is mainly manifested in the following areas: (1) the role of physical and mechanical: high-speed shear flow of broken produce aggregates. (2) Air blast, water was rapidly closed the gap in the soil in the air, by the uneven pressure caused by blasting, crushing of aggregate produced. Using of the PAM liquor in preventing from hardening skin, increasing the rate of soil seeping and decreasing soil erosion, existed lots of disadvantages. At home and abroad, people will be dissolved PAM sprayed on the surface and will join the PAM in the water of irrigation in generally. But these methods do not apply to dry areas. It is reason that dissolved PAM takes plenty of water and labor. In this issue, the use of spread in the soil surface dry PAM.The test used two kinds of soils-sand and sandy clay. Through micro-cell test, simulation border conditions, the paper researches that different characteristics of dry PAM and the speed of the three wet on the effects of infiltration rate of soil erosion of the two types of soil (loam, sandy clay loam). The kinds of wet speed:2.5,3.75,6.25mm min-1. The results show that moist soil infiltration mechanism of phase is different from the continuous flow phase; wet speed is caused by moist soil crust of one of the major reasons, soil crust makes increasing surface runoff, infiltration rate. For the loam, moist loams of the stability of the rate of infiltration and seepage have a significant effect on the cumulative. The greater the speeds of wetting, soil surface have a stronger degree of crust. For the sandy clay loam, the size of wet speed, the impact of infiltration and soil stability in the volume of the cumulative infiltration. Whether it is loam or sandy clay loam, moist speed had no effect on soil erosion. About wet speed, PAM characteristic to soil infiltration rate influence in the loam, sandy clay loam of experiments local. After the soil surface scatters different characteristic PAM, can increase the soil infiltration rate, reduces the surface amount of runoff, and reduces the soil erosion. It can enhance the utilization of irrigation and irrigation. For the sandy clay loam, No matter the size of wet speed, using low-molecular-weight PAM is cost-effective to increase the soil infiltration rate. For the loam, when the sub-hour speed, the use of low-molecular-weight PAM is more effective, when the sub speed larger, the use low-molecular-weight PAM with high molecular weight t more effectively, such as the same proportion of mixed, and different characteristics of PAM on soil erosion does not affect.