Rainwater Harvested Technology And Glycyrrhiza Uralensis Supplementary Irrigation Effect From Ski Hillslope In Ili Valley

The rainfall in Ili valley is abundant,but the utilization rate of rainwater is low.A large amount of rainwater is lost in the form of evaporation and runoff,and the water supply to vegetation is limited.Rainwater harvesting technology is an effective way to improve the utilization rate of rainwater,which is of important role to vegetation restoration and agricultural production.In order to explore the relevant parameters of rainwater harvesting technology with different slopes in the Ili Valley.This paper took the the ski hillslope surface of Ili Valley is taken as the research object,in different slopes of the slope to rainwater harvesting.By studying the change of rainfall in Yining City from 1970 to 2019,the rainwater harvesting effect of different slope plastic cloth and slope surface and the effect of supplementary irrigation on the growth of Glycyrrhiza uralensis.Combining rainfall conditions,rainwater harvesting characteristics and supplementary irrigation effect,the theoretical data are provided for the development of regional rainwater harvesting technology and supplementary irrigation agriculture.The main results were as follows:（1）Analysis of rainfall data in Yining City from 1970 to 2019 shows that the regional climate tends to be warm and humid,the rainfall types are mainly light rain and extreme rainfall.In recent 50 years,extreme rainfall has changed greatly.The extreme rainfall indices show an upward trend during 1970-2019,among which the PRCPTOT,RX5day,R95p and R10 show an upward trend visible.The increase rates were 15.2 mm×10a^-1、3.39 mm×10a^-1、9.35 mm×10a^-1、0.47 d×10a^-1,respectively.Less rainfall in August and September in the region,the remaining 5 months high rainfall and have their own characteristics,Heavy rainfall is more in April,rainfall is balanced in May,extreme rainfall is more and concentrated in June,and sudden extreme rainfall is prone to occur in July and October.At the same time,the extreme degree of rainfall increases year by year,which improves the flow production capacity of rainfall and enhances the regional rainwater harvesting potential.（2）In order to rainwater harvesting more effectively,the rainwater harvesting surface of the rainwater harvesting measures is set to a combination of plastic cloth and slope surface according to the rainfall characteristics.By analyzing the rainwater harvesting data of 5°,10°,15°,20°and 25°slopes,the runoff threshold of plastic cloth is between 0.07 mm and 0.10 mm,and the runoff thresholds of slope surface were 9.26 mm,7.70 mm,6.50 mm,6.25 mm and 5.85 mm,respectively.With the increase of slope,the rainwater harvesting amount and efficiency of plastic cloth and slope surface first increase and then decrease.When the slope is 18.4°and 24.6°,respectively,the plastic cloth and the slope surface had maximum rainwater harvesting amount and efficiency.Rainfall characteristics have great influence on rainwater harvesting amount and efficiency of slope surface,but have little influence on rainwater harvesting efficiency of plastic cloth.Parameters of formula for rainwater harvesting cellar are adjusted according to rainfall conditions,characteristics of rainwater harvesting and water use law.The cellar volumes of 10 m²plastic cloth+50 m²slope surface rainwater harvesting system on 10°,15°,20°and 25°slopes were 0.45 m³,0.59 m³,0.79 m³,0.77 m³and 0.84 m³,respectively.（3）Through the supplementary irrigation experiment of Glycyrrhiza uralensis,it was found that supplementary irrigation increased its biomass greatly.With the increase of aboveground biomass,underground biomass showed an increasing trend.the increase of underground biomass in non-irrigation plot was reflected in the synchronous increase of root diameter and root length,while the supplementary irrigation plot was more inclined to increase root diameter.According to the water requirement of 260.0m³/mu of licorice per year,planting 1 mu of licorice,the Irrigation ratio of plastic cloth to Glycyrrhiza uralensis on 5 slopes is 2.8-3.4:1.The irrigation ratios of slopes with different slopes to Glycyrrhiza uralensis vary greatly,and the irrigation ratios of 10°,15°,20°and 25°slopes ware 125.6:1,41.3:1,41.8:1 and 31.3:1,respectively.The required water cellar volume was between 132.6 and 138.3 m³.To sum up,The potential of rainwater harvesting in Ili Valley continues to increase,and the mountainous terrain provides a good foundation for the development of slope surface rainwater harvesting technology,rainwater harvesting and supplementary irrigation agriculture.Plastic cloth+slope surface rainwater harvesting mode can not only collect runoff from heavy rain,but also collect certain rainwater under the condition of large amount of light rain,reducing irrigation ratio of licorice.The test results can provide data reference for the development of Ili Valley regional rainwater harvesting and supplementary irrigation agriculture.