The Hydrus Simulation Of Soil Water Movement Based On Plant Addtion

There are many environmental problems in China in recent years, such as water shortage, severe desertification, salinization of many ranges of land and the reduced food production, all of these became an important factor which has restricted the development of our country’s economy. Find a reasonable and effective method to change the quality of soil and make the available use of water resource, has become a focus of the global research. At the same time, soil moisture movement has become an important subject in order to service the series of soil environmental problems. This paper through draws lessons from the study achievement of our country and foreign countries, study the method to change the quality of soil, such as crop stubble and straw returning, in order to explore the new methods to solve the problem. The objective of this subject is mainly to optimize soil structure and improve the efficiency of farmland irrigation. The method of this study combined two-dimensional indoor testing and HYDRUS software together, to analyze the condition of the soil moisture movement under plant blending process. Obtained the main conclusions as follow:(1) The two-dimensional motion rule of soil moisture in the soil bin testing is: cumulative infiltration amount increase gradually as time goes on, but the speed of increase gradually slow down and eventually turns to be stabilized; The wetting front’s curve of two-dimensional infiltration is similar to ellipsoid, the movement distance of wetting front in vertical is greater than the horizontal’s, but the difference is not big; Measuring the soil moisture content when the infiltration finished, it can be found that the soil water contain isopleth is similar with wetting front distribution, and the farther from irrigation ditch distance, the smaller the water content.(2) Adding different kinds or proportion addition into the soil will change soil properties, thus impact on soil moisture migration rule. There are some difference between the result of different kinds of treatments’influence.(3) Under the different kinds of addition, the influence on soil moisture movement regularity is shown as:the effect of corn leaves on soil water infiltration is obstructive, it will slow down the speed of water infiltration if add corn leaves into the soil, and it will make water spread in the horizontal direction, improve the water contain of soil at the same time; Corn cob have two characters, one is water-imbibition and the other one is discharge water along the side wall, the results of the influence will change according to the differ strength of the two characters, the other two kinds of deal methods should take into consideration.(4)Take the treatments with different mixing ration into contrast, the results show that the greater ratio is, the more obvious of the effect, especially to the effect of3%corn leaf blend treatment, it growth rapidly compared with1%corn leaf blend; For corn cobs treatment, the drainage performance predominates under1%ration blend treatment and the speed of water infiltration will be accelerated, when the ration of addition is3%, the water absorption is dominant, and the speed of water infiltration will be reduced, the water binding capacity will be improved.(5) Different depth of mixed layer have different effect on the soil moisture movement rule, because the difference of the depth will lead to different contact area and contract time. When the layer is deeper, the effect of addition layer will be strengthened, this not only hinder the water infiltration on vertical direction, but also improve the water binding capacity and diffusion effect.(6) Using HYDRUS software for simulate soil water characteristic curve, and fitting with the test data; Choose out the optimal experience model, is Van Genuchten model. Adopting the optimal model to simulate the two-dimensional infiltration under plant blending process, comparing the simulative data with the testing data, which include wetting front and soil water contain, the result shows that the similarity is above0.9, and the simulation effect is good.