Process And Simulation Of Water Transformation Of Wolfberry Tree Production In Inland River Irrigation Area

Drought and low water use efficiency?WUE?are two restrictions that obstruct the agricultural development of the inland river irrigation area in Northwest China.In this paper,we took Huaitou Tala irrigation distriction in Qaidam Basin,Qinghai Province as an experimental site,taking the representative crop Lycium barbarum L.?L.barbarum?as the object,and applied continuous field observation to investigate water transformation process between soil-atmosphere regulated by agronomic techniques,under drip irrigation condition,to achieve the scientific goal of saving water and increasing production and water use efficiency.On this basis,a model,named STEMMUS?Simultaneous Transfer of Energy,Mass and Momentum in Unsaturated Soil?,which considered soil airflow transport was selected to simulate the water transport process and discuss the pattern of water conversion under the scenario of increasing precipitation.The main conclusions were as follows:?1?Compared with the traditional flat no-mulching planting pattern?FN?,ridge-furrow mulching?RM?treatment significantly increased the 20 cm depth soil cumulative temperature?P<0.05?,and increased the soil water storage of 10-110 cm by 16.1%?2018?and 24.3%?2019?.At the same time,RM successfully reduced soil evaporation by 39.9%?2018?and 55.1%?2019?in compared to FN.Providing a good soil water and heat environment for crop growth and production.?2?Validation results showed that STEMMUS model can well simulate the dynamic variations of soil water,heat and evapotranspiration in arid inland river irrigation area.For soil temperature simulation,considering dry air coupling had little effect on modeling precision.While for shallow soil water simulation,the simulation differences had a positive correlation with the increase of rainfall/irrigation.When the rainfall/irrigation reached 20mm,the difference increased to 1.2%.In addition,the differences in evapotranspiration and evaporation modeling also showed a positive correlation with the increase in water input.When the water input attained 30 mm,the difference increments reach 0.3 and 0.2 mm d^-1,respectively.Coupling Shuttle-Wallace?S-W?dual-source model successfully improved the accuracy of evapotranspiration(index of agreement??9?values increased by 5.8%?and evaporation simulation(?9 values increased by 13.0%?compared with the original Penman-Monteith?P-M?algorithm.?3?The 10-20%rainfall increment had little effect on the dynamic process of soil temperature,the maximum average difference in the simulations of the 0-100cm profile is only 0.8%,but significantly increased the soil water storage of 10-110cm soil layer,enhancing soil water storage by an average of more than 7%under 20%rainfall increment.RM increased the water consumption ratio?transpiration/evapotranspiration?by 0.3%?10%rainfall increase?and 0.4%?20%rainfall increase?respectively.Under the assumption that the yield increases by 10%when the rainfall increment attained 10%,WUE increased by7.2%-9.6%,and when the rainfall increment achieved 20%,WUE increased by 2.3%-5.2%.?4?In the measurements from 2018 to 2019,the fruit diameter and fruit length of wolfberry under RM treatment were significantly higher than other treatments?P<0.05?,and RM had the highest L.barbarum production,WUE and net economic income.Compared with FN,RM increased the production of wolfberry by 16.5%?2018?and 26.6%?2019?,increased WUE by 3%?2018?and 22%?2019?,and enhanced net economic income by 11.74%?2018?and 31.94%?2019?.However,no significant difference was found in fruit vitamin C content and total sugar content among treatments.For the northwest inland river irrigation area,ridge-furrow mulching planting is the best agronomic technique to promote crop growth and increase yield and WUE.Simulations suggested that rainfall increment efficiently incresaed the crop root zone soil water storage;and WUE would be increased under the premise that the yield increased.This study provides scientific and technological support for the efficient use of water resources in the northwest inland river irrigation area.