Study On Water Uptake By Plant Roots In Intercropping Patterns

Soil water movement is a very important aspect in researching for that of material and energy transports in SPAC system, and for water resources utilization and management in water saving agriculture. Moreover, quantification of root water uptake is basis for simulating water soil movement in the soil-plant system. Since 1950s, researchers, from China and abroad in many fields, such as plant physiology, agricultural water and soil engineering, soil physics, hydrology and water resources, have made great efforts in studying of both mechanism and characteristics of water uptake by plant roots and root-water-uptake model in different aspects. However, these studies more focus on the traditional monoculture pattern and less on the rule of water uptake by plant roots in intercropping patterns. In recent years, intercropping, as one of the effective methods of water-saving and production-increasing, has been getting more and more attention. In this paper the intercrop pattern of winter wheat and spring maize and the method of field experiment are adopted to study the rules of root-water-uptake in intercropping patterns, and finally the model of root water uptake is established. This provides the theory and technology support for water movement in SPAC system in intercropping patterns. By the analysis of the field experiment data, some conclusions can be got:(1) Analyzing roots density of winter wheat and spring maize under intercropping, we concludes that both winter wheat roots and spring maize roots expanded large range in horizontal direction to make the most of soil water of lateral direction. Two-dimensional spatial distribution of root-weight density of winter wheat intercropped can be fitted well with power function, and that of spring maize intercropped can be fitted well with exponential function, the results are:Winter wheat:Spring maize: R_m(X,Z,t) = e(2) The affecting factors of soil evaporation for winter wheat are analyzed under two different planting patterns, and the result shows that the reference crop water requirement, leaf area index and the moisture of surface soil are the main influencing factors. With the regression analysis, the estimated models of soil evaporation are established for monoculture winter wheat and intercropped winter wheat. By contrasting the soil evaporations of two different planting patterns in spring maize field, it indicates that the process of soil evaporation for spring maize field can be divided into two different phases. The first one is the intercrop period of winter wheat and spring maize, in which E_单>E_间;The second one is the period after the harvest of winter wheat, in which E_单