Study On Root Distribution And Water Uptake Model Of Jujube Tree At Drip Irrigation Condition In Arid Area

The shortage of water resources and water and soil environment deterioration has become an important factor restricting China’s sustainable development of agriculture. The shortage of water resources is serious especially in the northwest of China. On the one hand, the land of the northwest area is very wider but the amount of water resources is lower. On the other hand, ground irrigation which is not a reasonable irrigation methods was used often, so the water resources which has been short were wasted. So accurately mastering the mechanism of plant roots absorbing water and understanding the distribution of soil water consumption is particularly important to make a reasonable irrigation system and ensure the agricultural water-saving and high and stable yield.This article accorded to the jujube planting current situation around the Tarim Basin, the jujube is the object of study in the Agricultural Science and Technology Demonstration Park in Aksu area, in order to explore the root distribution and the law of water uptake. Designed to provide a theoretical basis for the scientific management of the water that jujube tree needs around the Tarim Basin. Through measuring soil water content by TRIME and Hydra system, measuring transpiration by DYNAGAGE Wrap-Sap Flow, measuring evaporation by Mini-lysimeter, measuring meteorological factors by Vantage pro2automatic meteorological station and so on, experiment of water uptake of jujube root was carried out. On the basis of test, adopting the improved Feddes model simulated the distribution of root water uptake and then using soil water dynamics verified the accuracy of the model. The main research contents and results summarized as following:(1)The dynamic data of soil moisture content which was observed by Trime and Hydra show that the soil moisture content shows an increasing trend follow the soil depth and the soil moisture changes more sever when the spot is near the soil surface.(2) The distribution rule of jujube root was analyzed according to the measured root data under drip irrigation condition. The result shows that the root is more near the tree in horizontal or vertical direction. Whether the one-dimensional or the two-dimensional effective roots length density distribution of jujube trees all of them can be fitted by exponent function. Simulation accuracy is higher.(3) The rate of root absorbing water relate closely with transpiration, the effective root length density and the soil water potential in root zone. The root water uptake model was established according the improved Feddes model and measured data. The established root water uptake model was validated by according with the principle of soil water dynamics and combining with the one-dimensional soil water movement equation which contents root water uptake and the measured soil moisture dynamics data. The result shows that the model can basically reflect the root water uptake condition of jujube tree. There is a certain value to use.