Effects Of Different Covering Cultivation On Soil Hydraulic Process And Model Simulation

A widespread measure for improving crop yield and water use efficiency in the northwest of China is the ridge-furrow of agricultural production system combined with ridging, straw mulching and plastic film mulching. However, it is lack in studying, how and to which understand the mode of heat and water migration mechanism is hereby modified. In this study, we take the main crops of winter wheat in arid as the research object. Using the long-term field monitoring data of the profiled soil moisture and temperature, as well as the data of the collected roots and the determination of soil physico-chemical properties in the laboratory, Optimized model parameters by the root system in combination with Hydrus-1D model, we describe the soil water and heat coupling migration rule under different covers. For efficiently using the model to simulate and predict the change of the farmland soil heatwater transport under different management models in the loess plateau, further to provide a basis of accurate quantification of crop water consumption and water use efficiency. The experiment consisted of four treatments: un-mulching(T0), straw mulching(T1), half –filming on soil ridges(T2) and half –filming on soil ridges + straw mulching in furrows(T3). The results show that:1) From jointing stage to the mature period of winter wheat, the dynamic changes of the soil moisture was not only affected by the size and distribution of precipitation, but also was controlled of tillage measures. The soil moisture content at 15 cm layer of T3 was notably lower than other treatments in wet year, and was markedly higher than other treatments in dry year. It showed that the treatment of T3 had a effect of accepting rainwater and holding soil moisture conservation.2) There were showed a sinusoidal function curve with different treatments of winter wheat at 15 cm layer of soil profile. The cultivating conditions of T2 had obvious effect of warming, on the contrary, T1 had a cooling effect.3) The more roots growth of the winter wheat were concentrated, the soil moisture content was smaller in the farming layer of soil. The depth which concentrated area in winter wheat root system in soil profile: T2 < T3 < T0/ T1, and suggested that ridge tillage cultivation was conductive to reduce the concentration depth of root system.4) There was a binary polynomial regression relationship between Winter wheat root length and the ground biomass, T1 had a better effect among them, which increased water use efficiency and promoted the accumulation of production. Root length increased with increasing the biomass in the early growing stage, and decreased with increasing biomass in later growing stage. The cultivating conditions of T1 was best among the three treatments in promoting the root growth of winter wheat, improving the water use efficiency and biological yield.5) Hydrus-1D model is capable of simulating soil water content dynamics well, so as to it can be better used for analyzing soil heat and water processes simulation in different covering cultivation modes. On the basis of water quantity balance calculation, the treatment of T3 reduced the evaporation, increased the transpiration and soil water consumption.