Numerical Simulation Of Soil Water Deep Percolation Of A Jujube Orchard In Arid Region

This study relying on the Project Supported by National Technology"Integrated and Demonstrated Water Saving Technology of Modern Agriculture in Arid Region",the jujube is the object of study in the Experimental Forestry Centre in Aksu Area,in order to discuss the characteristic of deep percolation and the law of water consumption under the irrigation and so on,through measuring soil water content by TRIME and Hydra system,measuring deep percolation by the tray of incepted seepage water,measuring LAI by TRAC,measuring meteorological factors by Vantage pro2 automatic meteorological station and so on, experimention of deep percolation was carried out.Based on the experimention,the characteristic of deep percolation,law of water consumption and translation of irrigation quota were simulated and analyzed with the HYDRUS-1D;In order to sieve appropriate micro-irrigation method for grown jujube,through measuring the leaf,diameter of jujube crown and else growth index,measuring yield actually,measuring the appearance,sapor and nutrition of fruit and else quality index,experimention of micro-irrigation method was carried out,then united the characteristic of water consumption and deep percolation volumes by simulated,effects of different irrigation methods on jujube were analyzed,it's important significance to exactly estimate the deep percolation of soil water and sieve appropriate irrigation method.The main research results summarized as following:(1)Based on the data obtained from experiment,a one-dimensional model(HYDRUS-1D)of soil water moving was developed,results of simulation were verified and shows that,the results of simulation represent preferably the field soil water movement.So the deep percolation of soil water analyzed with HYDRUS-1D model is viably.(2)Compared with percolation volumes of different calculational methods,it shows that,the simulated result and calculational value of soil water balance equation are exacter under surface irrigation,irrigated excessly result in the deep percolation of soil water very serious,the cumulate quantity of deep percolation were 1124.0mm and 1032.4mm respectively,which account for about 60.0% and 55.1% of the total amount of irrigation respectively;The simulated result on the high side,the calculational value of soil water balance equation and measured value actually are exacter under surface drip irrigation,the cumulate quantity of deep percolation were 103.4mm and 116.9mm,which account for about 10.9% and 12.3% of the total amount of irrigation respectively,two times of surface irrigation are the main reason for deep percolation and it adopted the method of high frequency and little irrigation quota reduced deep percolation volumes effectively.(3)From Early flowering period to Post anthesis stage,the water consumption give priority to evaporation;Come into Post anthesis stage,the evaporation will become imperfect and the transpiration will become enganced;From Fruit expanding process to Fruit pre mature,the water consumption give priority to transpiration;Come into Fruit post maturation stage,the water consumption give priority to evaporation again.The total amount of irrigation under surface irrigation mainly translated into groundwater,the water consumption was 802.6mm,accounting for only 42.9% of the total amount of irrigation used for consumption;The total amount of irrigation under surface drip irrigation and micro-jet mainly used for the jujube,the water consumption were 805.3mm and 842.6mm respectively,accounting for 85.0% and 88.9% of the total amount of irrigation used for consumption respectively;And it was preliminarily identified that the water consumption of jujube in growth period is about 800.0mm,the stage of Post anthesis stage to Fruit expanding process is the critical period of water demand and the evapotranspiration is about 6.0mm/d.(4)Effect of different irrigation methods on water consumption,growth,yield and fruit quality of jujube were analyzed,the results show that,the water consumption under micro-jet is largest,it accounting for 88.9% of the total amount of irrigation used for consumption and the water consumption is larger than else irrigation method in the growth stage,it improve the environment of jujube orchard.Compared with surface irrigation,surface drip irrigation and micro-jet decreased irrigation quota 49.4%,and increased yield 23.0% and 17.0% respectively,the WUE is 2.4 times and 2.3 times more than surface irrigation respectively.The rationalization-satisfaction index was 0.52 under micro-jet,it's the highest and surface drip irrigation was the next.In sum,the micro-jet is the best micro-irrigation method for jujube.