Simulation Of Rainfall Conversion In North China Farmland Under Straw Mulch

In China, water shortage is the major factor restricting the development of national economy. In the case, especially in the north facing agricultural production in arid areas the situation has become more critical. Under the straw mulch, through the indoor and field experiments to study the law of crop evapotranspiration, the transformation process of quantitative precipitation, to understand the precipitation transformation and control mechanisms, and as a basis for optimal control of precipitation in northern dryland conversion use.It was random to design the field experiment arrangement, setting 25% coverage, 50% coverage, 75% coverage, 100% coverage, plastic mulching and non-covering. Trend line on the test results and analysis of variance, it showed that: mulch spring corn yield and the size of the elements are closely related, the greater the coverage amount, the higher corn production, the production of covering 75% was increased by 35.06% than non- covering. Analysis found that coverage can significantly improve water use efficiency, which of the covering 75% treatment than non-mulching treatments increased 33.2%.According to soil water dynamics and non-saturated soil water flow theory, establishing under straw mulch maize root water uptake model and soil water-flowing model, to determine some model parameters by experiments .It adopted the finite difference method for discrete the model, with in the MATLANB software to solve the model, and validated with experimental data. The results show that the straw mulch significantly influenced on the soil layer 0 ~ 60cm of soil moisture content. The model reflected under the different straw mulch the field of soil temperature and heat transferring in the variation; it was consistent with the experimental data.It shows that the different straw mulch amount have an effect on moisture, soil temperature at 0 ~ 30cm of soil, yield and some physiological indexes. The results show that the larger straw mulch amount, inhibit evaporation effect is more obvious. It can significantly improve the yield and water-saving effect of the spring corn under straw mulch. It raised the reasonable straw mulch amount for the local. The water and heat transfer research under straw mulch, not only revealed the straw mulch for moisture and heat transport regular pattern, but also analysis covering the amount of maize yields and components of the relationship, optimization of structure for the establishment of precipitation laid a theoretical foundation. It has great application value to increase the food production and water shortage stress of inland arid areas.