PAM 喷施量与施用方式对风沙土风蚀的影响.

Sandstorm and desertification have posed a worldwide threat to fix quicksand and reduce soil wind erosion for people's living environment. PAM (polyacrylamide), a kind of linear polymer, has been widely used in metallurgy, building materials, paper, mineral processing, oil production, sewage treatment and other industries due to its strong hydration and viscosity, and thereby it is also expected to resist the wind erosion. There is no any toxic effect on soil when spraying PAM solution on the soil surface. The main reason is that the sprayed PAM solution can form hard crust on the soil surface, and then the crust can effectively protect soil from wind erosion. However, the crust condition and wind erosion resistance of PAM are closely related to the PAM application methods, spraying amount and structure of soil. Moreover, high concentration of PAM solution can be a high viscosity, difficult to dissolve or spray, and lead to inconvenient spray on the surface of sand dune or soil. Taking the aeolian sandy soil as test material, this study aims to explore the optimal spraying amount and application method of PAM to prevent wind and fix sand, while reduce water consumption, by tailoring the properties of air-dried soil (aeolian sandy soil) and saturated soil. Specifically, the effects PAM of spraying amounts on surface crust, moisture and soil wind erosion of air-dried soil were investigated to determine the optimal spraying amount of PAM, and then, an optimal amount of PAM was used in the following ways: dry PAM sprinkled, dry PAM sprinkled+spraying water, and spraying PAM solution, to explore a facile method for the application of PAM. The results showed that the soil shear strength, the coverage and thickness of soil crust after PAM treatment increased with the increase of PAM spraying amounts, all of which were significantly higher than that of air-dried soil and saturated soil. The soil moisture after PAM treatment was significantly higher than that of air-dried soil and saturated soil over time. When spraying PAM of 1, 2, 3, and 4 g/m², the wind erosion were 26.83%, 14.10%, 13.01% and 13.00% of air-dried soil, whereas, 28.78%, 15.12%, 14.02% and 13.94% of saturated soil, respectively. When the spraying amount of PAM reached 2 g/m², PAM can effectively reduce the wind erosion of aeolian sandy soil. After 2 g/m2 dry PAM sprinkled+spraying water and spraying, the coverage and thickness of soil crust, and soil shear strength were higher than that of air-dried soil, saturated soil and dry PAM sprinkled. In dry PAM sprinkled treatment, the coverage of soil crust was lower than that of saturated soil, but higher than that of air-dried soil, whereas, the thickness of soil crust and soil shear strength were higher than that of air-dried soil and saturated soil. In dry PAM sprinkled+spraying and spraying PAM solution, the soil moisture was higher than that of air-dried soil, saturated soil and dry PAM sprinkled. In dry PAM sprinkled, the soil moisture was basically the same as that of air-dried soil. The soil wind erosion after dry PAM sprinkled, dry PAM sprinkled+spraying water and spraying PAM solution were 53.13%, 11.17% and 6.35%, of air-dried soil, respectively, and 76.34%, 16.05% and 9.12%, of saturated soil, respectively. In the dry PAM sprinkled+spraying water, the resistance of wind erosion was close to that in the spraying PAM solution on the surface of aeolian sandy soil. In order to save water and manpower when preparing and spraying the PAM solution, two measurements were proposed. One is that 2 g/m² PAM powder can be dry sprinkled on the surface of sand dunes and soil before rain in the wind-sand areas according to weather forecast. Another is, after dry PAM powder sprinkling, the sprayed water on the surface of sand dunes and soil can effectively fix the quicksand and reduce the amount of soil wind erosion. [ABSTRACT FROM AUTHOR]