Numerical Study On Regulation Of Soil Thermal Regime By Mulch Culture

Polyethylene mulch is an efficient method for raising soil temperature and maintaining soil moisture content, which has been widely used worldwide to improve the hydrothermal regime of soil and increase crop yield, as it eliminates evaporation by blocking moisture transfer and has a greenhouse effect on the underlying soil by changing the albedo of the ground surface and influencing the long wave radiation from the ground surface. Here we study the applicability of this method in the forest regions in the Qilianshan Mountain, including its ability to promote soil thawing and improve soil temperature.(1) Based on a thorough retrieval and systematic analysis of the related literature, the effects of different factors on the hydrothermal regime of soils are reviewed;(2) The method for calculating the net radiation on soil surface according to the basic principle s of meteorology and solar radiation theory, and that for calculating the air temperature at different latitude and elevation with various slopes are summarized(3) The annual freezing-thawing cycle from a bare soil surface is simulated using a commercial software with the appropriate climate and other factor values of the forest regions in the Qilianshan Mountain, and the results compared are with in situ data in the literature to prove applicability of the method and validity of coefficient values. Then, the thermal regime in the ground covered by Polyethylene mulch using the same simulation method and coefficient values, it is found that Polyethylene mulch can decrease the maximum frozen depth and accelerate the thawing from the frozen ground surface in spring.