Effects Of Winter-Spring Irrigation On Soil Water-Salt Dynamics,Growth,Yield And Quality Of Jujube Under Drip Irrigation In Southern Xinjiang

Object:Xinjiang was an important red jujube producing area in China.Soil salinization restricted the sustainable development of agriculture in Xinjiang.Winter-spring irrigation was a measure to improve soil salinization in the irrigation area of Southern Xinjiang.However,unreasonable winter-spring irrigation not only caused serious a waste of water resources and could not effectively wash and press salt,but also raised the groundwater level,causing secondary soil salinization in the original good land,resulting in unguaranteed the yield and quality of jujube.This thesis studied the effects of different winter-spring irrigation methods and amounts on soil water and salt dynamics in the non-growth period,initial soil water and salt distribution in the growth period,growth,yield,and quality of jujube in jujube garden.It obtained the suitable winter-spring irrigation mode of drip irrigation red jujube in Hotan area,so as to provide a theoretical basis for efficient utilization of irrigation water and prevention and control of soil salinization of red jujube in southern Xinjiang.Methods:Through field plot experiment,the jujube of locally 11a(planted in 2010)was selected as the research object.In this study,we set two irrigation methods(i.e.,T1:winter and spring full irrigation,T2:winter irrigation)and five irrigation amounts(i.e.,W1:900 m~3/hm~2,W2:1050 m~3/hm~2,W3:1200 m~3/hm~2,W4:1350 m~3/hm~2,W5:1500 m~3/hm~2).Non-winter and spring irrigation was used as control(CK).A total of11 treatments were repeated 3 times.Based on the principal component analysis and grey relational analysis,quality indicators of red jujube were comprehensively evaluated,and the quality index of red jujube were quantified by the principal components comprehensive score and grey correlation.Then,the effect of soil moisture conservation and salt pressing after irrigation,as well as the growth,yield,and quantitative quality indexes of red jujube were comprehensively evaluated by the TOPSIS analysis method.Results:(1)The replenishment effect of winter and spring full irrigation treatment on soil moisture of jujube garden was better than that of winter irrigation treatment,and the replenishment effect of the two on soil moisture of jujube garden was significantly higher than that of non-winter and spring irrigation treatment.With the irrigation amount increased,the peak value and range of water"wet area"formed in the soil layer increased after winter irrigation.When the soil moisture slowly decreased to the minimum value,the range of water was formed.When the ground temperature rose,the phenomenon of"returning moisture"in the soil was more obvious.Spring irrigation had a better replenishment effect on soil moisture,which was more conducive to the germination of red jujube in the coming year.(2)The leaching effect of winter irrigation treatment on soil salinity of jujube garden was significantly better than that of winter and spring full irrigation treatment,and the leaching effect of non-winter and spring irrigation on soil salt was lower than that of winter and spring full irrigation and winter irrigation.With the irrigation amount increased,the"low-salt area"on the soil surface increased after winter irrigation and the leaching effect of soil salinity was better.When the salt content of each treatment soil layer was stable,the deeper the"low salt area"formed.After the ground temperature rose,the phenomenon of"returning salt"in irrigation treatment was more obvious.During spring irrigation,the leaching effect of soil salinity was more obvious,and the higher soil moisture content could be better maintained.(3)The improvement effects of winter and spring full irrigation treatment on the initial soil water and salt,growth(fruit setting rate,shoot growth rate),single fruit weight,yield,and quality index(fruit shape index,edible rate,total sugar,total acid,vitamin C and soluble solids)was the greatest,followed by winter irrigation treatment,and the lowest was non-winter and spring irrigation treatment.Non-winter and spring irrigation treatment had the greatest effect on the improvement of irrigation water use efficiency,followed by winter and spring full irrigation treatment,and winter irrigation treatment was the smallest.With the irrigation amount increased,the initial soil water and salt,fruit setting rate,shoot growth rate,single fruit weight,yield,fruit shape index,edible rate,and total sugar of red jujube increased,irrigation water use efficiency decreased,and the total acid,vitamin C and soluble solids increased first and then decreased.Conclusion:T1W4 treatment(winter and spring full irrigation,irrigation amount 1350 m~3/hm~2)could not only enhance the effect of irrigation on soil moisture conservation and salt compression,but also improve the growth(fruit setting rate,new shoot growth rate),yield and quality(fruit shape index,edible rate,total sugar,total acid,vitamin C and soluble solids)of jujube.It was a suitable winter-spring irrigation mode in Hotan area of Southern Xinjiang.