China is one of the countries with serious water and soil loss. The countryâ€™s current soil and water loss area is 3,673hm2, accounting for 38.% of the country's total land area. The principle of loess height is the most serious soil erosion area in China. The erosion modulus is 5000~10000t/km2. Even up to the top of the world. According to many years of research, the main driving force for soil erosion in the region is the scouring power generated by rainfall runoff. If surface runoff can be cut by some means, the soil erosion power can be eliminated or reduced, and through some means, it will be cut. The use of runoff can achieve the dual goal of eliminating soil erosion and relieving the drought and water shortage of crops and seedlings. At present, the treatment of soil erosion has traditionally used engineering biological and agricultural measures. In recent years, the prevention and control of soil erosion by chemical measures has become a new research area. The use of high-molecular polymers as soil conditioners creates and stabilizes soil water-stable aggregates by artificial means. Improving soil structure, strong soil permeability and anti-corrosion capacity, and reducing soil erosion have become new ways to prevent soil erosion.
Dozens of macromolecule polymers were tested in the soil for infiltration experiments. Three high-molecular polymers with obvious effects on the infiltration of polyacrylic acid, polyvinyl alcohol, and urea-formaldehyde resin were selected for soil physical properties. The results of systematic bifurcation of the effect showed that the polymer could indeed improve the soil structure, add water-stable aggregate content, strong soil permeability, permeability, and water holding capacity. On this basis, this paper mainly applied these three different concentrations on outdoor slopes. The high-molecular polymer was subjected to scouring experiments under simulated artificial rainfall conditions. The purpose was to study the regulation and control functions of high-molecular polymers on surface runoff, including the effects on the process of flow generation and corrosion protection, and the results were screened out. The most effective and economical polymer for preventing and controlling soil erosion. Fund Project: The National 863 Program â€œEfficient Rainwater Harvesting and Utilization Technology and Efficient Utilization of Water-based Water-saving Water Resources. Shaanxi Yangling Northwest A&F University Chinese Academy of Sciences Ministry of Water Resources and Soil and Water Conservation Research National Water saving irrigation Yangling Engineering Technology Center, 712100 to determine its appropriate amount.
1 Materials and methods 1.1 Polymer materials Polyacrylic acid: commercially available, soluble in water, light yellow viscous liquid outside, with cementation, can be used as a flocculating agent water blocking agent, paper treatment agent, structure modifier, Mostly used for water treatment agents, it is an environmentally friendly material.
Polyvinyl alcohol: commercially available, white particles, easy to absorb water and swell, chemical properties are relatively stable, is a good soil structure improver, industrially used as a sizing of paper fabrics, pharmaceuticals, photographic industry, emulsifiers and ceramic bonding Urea formaldehyde resin and other agents: It is a kind of phenolic resin, which has a high adhesive force, a brown viscous emulsion, and is easily soluble in water. It is used by the industry for adhesives and water treatment agents that are non-toxic and harmless.
1.2 Test preparation test In the Yangling Water Conservation Demonstration Garden in Yangling, Shaanxi, a micro-sprinkler was used to simulate artificial rainfall for slope erosion tests. The rainfall intensity was controlled at 1.0 mm/min, and each rainfall duration was 1 h. The scrubbing tank length was 5. 2 m wide. The gradient is Â° to reduce the number of experiments by dividing the 2m width into 3 equal parts. The middle part is divided by PVC plates. The area of â€‹â€‹each plot is 0.6K 5.36m2. There is a water outlet at the lower end of each plot to contain the runoff and soil erosion. the amount. The soil sample is selected to be representative Guanzhong Lou soil, with a depth of 40cm in the plot, a 35cm layered filling height, a bulk density control of approximately 1.20g/cm3, and a water content control of approximately 17. The soil surface will be smoothed before the actual test. Properties are shown in Table 11.3 Test treatment In the well-organized plot, three types of macromolecule polymers are sprayed at different proportions (polyvinyl alcohol is mixed) on the surface of the soil. Specific concentrations and application methods are shown in Table 2 for the same type. For the compounds, there are six treatments. In each treatment, the soil moisture content was measured after the rainfall experiment and the sediment content was measured after the rainfall experiment. The surface damage was observed. Each treatment was set up with 3 repetitions. Change the soil and change the position of each experimental factor to reduce the error as much as possible.
Table i Test Soil Physical Properties Soil Texture Bulk Density Total Holes Percentage of Particulate Content Water Stability Type Intersity 2 Effects of Polymers on Control of Soil Erosion Effects Runoff is one of the main drivers of water erosion on slopes. The greater the runoff, the greater the soil erosion that occurs. Surface runoff directly removes surface soil and exacerbates soil erosion. Therefore, reducing surface runoff also reduces soil loss. High-molecular polymers not only increase the amount of soil aggregates, but also form a certain amount of colloidal substances, enhance affinity with soil particles, and increase soil infiltration. Infiltration, reduce surface runoff, increase soil erosion resistance 9149n (application of polyacrylic acid LT and viscous action of high polymer, so that the soil to form a better granule structure, the interaction and slippage between the molecular chains make the top soil resistant The rushing capacity is greatly enhanced, weakening the mechanical damage and transport ability of the water flow to the topsoil.
Under the rainfall of 1.0 mm/min and time of 1 h, the changes of the amount of erosion of the polymer at different concentrations showed that the sediment content carried by the rainfall runoff after treatment with the polymer was significantly reduced. Polyacrylic acid treatment effect is most obvious, can greatly reduce the amount of soil loss, an average of 71.9 UF resin than the control, the sediment content decreased by 55.14, polyvinyl alcohol was the worst sediment content decreased by 47.41%. It can also be seen that with the increase of the application amount, the sediment content also decreases accordingly. The concentration of polyacrylic acid was 4. %~6.(%) When the sediment amount was only 137g, it was 4.9 times that of the control, which was 79.4% less than the control and the soil loss when the urea resin concentration was 10.0%~125%. 71.3% less than the control. When the concentration of polyvinyl alcohol is 10% to 20%, it is 61.0% lower than that of the control. This shows that in the concentration range of high molecular polymer, the erosion amount is reduced to the lowest concentration is too low or too high. The mitigation effect of macromolecule polymers is mainly due to the fact that the concentration of high molecular weight polymer is too low, the effect on soil improvement is not obvious, soil permeability is not improved, and the runoff to surface erosion ability is not weakened. Polymers do not fully react with soil particles. Excess polymer molecules and water expand and block the pores of the soil. As a result, surface runoff has not been infiltrated in situ, causing erosion to increase the erosion of the polymer on the slope. The influence of quantity 23 Determination of suitable concentration of macromolecule polymer bookmark8 From the analysis of the above experimental results, it can be seen that macromolecule polymers have significant effects on soil improvement, surface runoff regulation and soil erosion prevention, and The effect of concentration increase showed a significant increase, and the effect became stable when the concentration reached a certain value. Therefore, through the above experimental study, the optimum concentration and appropriate amount of each polymer (Table 3) can be determined from the following table. It can be seen that the effect of polyacrylic acid is the most significant, followed by urea-formaldehyde resin, the worst is polyvinyl alcohol polymer to improve the soil erosion control effect is obvious, in the appropriate concentration range is only about 1.50 æ¯ per square meter, used in In the field of soil and water conservation, it is easy to operate, inexpensive, and economically feasible, so it has the most suitable concentration and suitable amount of the most used polymer before Table 3. The appropriate name for the appropriate concentration of the cost of the compound./kg-1 runoff Compared with the control, the amount of erosion decreased compared with the control.å…€ m-2 Polyacrylamide-urea-formaldehyde resin Polyvinyl alcohol 3 Conclusion After spraying three kinds of high-molecular polymers on a stable rainfall downhill, the soil structure can be improved, the production time can be delayed, and the production time can be reduced. The surface runoff and soil erosion amount were more significant with the increase of concentration. The average was 7 minutes and 45 seconds longer than the control, and the runoff coefficient was flat. 0.3871, 4205% less than the control and 58% less soil erosion. For the same kind of polymer, with the increase of the concentration, the runoff takes longer and the runoff coefficient shows a declining trend. The amount of erosion is also corresponding. cut back.
According to the comparison of surface runoff regulation and anti-corrosion effect of three kinds of macromolecule polymers, polyacrylic acid had the best comprehensive effect, followed by urea-formaldehyde resin, and the worst concentration range of the three types of macromolecule polymers with polyvinyl alcohol was high polymer. As a new technology for the control of rainfall and runoff, the effect of improving soil structure, controlling slope runoff, and controlling soil erosion is obvious. In the future, it is necessary to further study the duration of its effect, as well as the corresponding construction process and project life, and proposes that This technology can be combined with traditional soil and water conservation measures and may achieve optimal control of rainfall runoff on the slope.
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