Effects Of Different Irrigation Treatments On Water Consumption Characteristics,Yield And Quality Of Chinese Dates In Minqin

China is a relatively poor country of water resources,the spatial and temporal distribution of water resources is not balanced,the per capita water resources is less,and the water resources in Northwest China are scarce.Drip irrigation is a very effective way of water-saving irrigation in arid and water deficient areas.Based on the characteristics of water-saving and high yield of drip irrigation technology and the characteristics of drought tolerance of jujube trees,drip irrigation jujube trees are suitable for planting and development in arid areas of Northwest China.Jujube is one of the characteristic economic fruits widely planted in Minqin County.For a long time,due to the lack of scientific irrigation system,the yield,quality and economic benefit of jujube are low.In order to explore the suitable local irrigation method of jujube,this study carried out the research on the effect of different irrigation amount on water consumption characteristics,yield and quality of jujube under drip irrigation condition in Minqin Qinfeng Forestry Experimental Station in 2020,in order to explore the suitable irrigation system of jujube in northwest arid area.Taking local 7-year-old Junzao as the research object,three drip irrigation treatments T1-T3（irrigation quota:270 mm;337.5 mm;405 mm）and one furrow irrigation control treatment CK（irrigation quota:810 mm）were set for field experiment.The effects of different irrigation treatments on water consumption characteristics,growth morphological indexes（new shoot growth,jujube hanging growth,crown diameter and fruit setting rate）,leaf and fruit indexes（chlorophyll,leaf thickness,fruit transverse and longitudinal diameter,fruit shape index and single fruit weight）,yield and water use efficiency,quality indexes（soluble solid content,total sugar content,total acid content and fruit weight）of local jujube were studied Finally,six indexes were selected to evaluate the comprehensive benefits of different treatments according to the theory of information entropy,and the suitable irrigation scheme was determined.The main conclusions are as follows:（1）During the growth period of jujube trees,the daily reference crop evapotranspiration ET₀ showed a trend of first increasing and then decreasing,and the peak value appeared at the end of June;the variation curves of soil water content and soil depth of each treatment were mostly lower in the surface and deep layers,and higher in the middle and upper parts,and basically reached the peak value at the soil depth of about 40 cm.The overall trend of soil water storage of different treatments is that the more irrigation,the higher the soil water storage;the differences in each growth period are relatively large,specifically for the smallest soil water storage in germination and leaf expansion stage,and the difference is larger than the other three growth periods,but the changes in flowering and fruit setting stage,fruit expansion stage and fruit maturity stage are not significant.The water consumption of different treatments was similar in different growth stages,the period with the most water consumption was the fruit expansion stage,and the water consumption of each treatment increased with the increase of irrigation amount;the crop coefficient Kc of each treatment was the smallest in the germination and leaf expansion stage,and then increased continuously in the growth stage,reached the peak in the fruit expansion stage,and then decreased in the fruit maturity stage.（2）Through the continuous monitoring of different growth morphological indexes of jujube trees under different irrigation treatments,the results showed that under the experimental conditions,the increase of irrigation amount had a promoting effect on the growth length of new shoots of jujube trees,but the promoting effect was not significant.The jujube hanging length and crown diameter of jujube increased with the increase of irrigation amount,but when the irrigation amount exceeded a certain limit,increasing irrigation again could not significantly increase the jujube hanging length and crown diameter of jujube;under the experimental conditions,the increase of irrigation amount had a significant promoting effect on the fruit setting rate of fruit trees,but when the irrigation amount exceeded a certain limit,increasing irrigation could not significantly increase the jujube hanging length and crown diameter of jujube After a certain limit,increasing irrigation can not significantly improve the fruit setting rate of jujube.（3）Through the continuous monitoring of leaf and fruit growth indexes of different irrigation treatments,the results showed that under the experimental conditions,the SPAD value of each treatment reached the maximum at the fruit expansion stage,and the increase of irrigation amount could improve the SPAD value of jujube leaves,but the effect was not significant;under the experimental conditions,the increase of irrigation amount could improve the leaf thickness of jujube But the effect is not significant;under the experimental conditions,irrigation amount and fruit longitudinal diameter have a positive correlation,when the irrigation amount reaches T3 treatment level,the increase of irrigation amount can not significantly increase the fruit longitudinal diameter;irrigation amount can improve the fruit transverse diameter,but it is not significant;under the experimental conditions,the single fruit weight of jujube will increase with the increase of irrigation amount,but when the irrigation amount reaches T3 treatment level,the increase of irrigation amount can not significantly increase the fruit longitudinal diameter When the amount of irrigation reached T3,the single fruit weight of jujube could not be significantly increased by increasing irrigation amount（4）The yield of CK treatment was 11.34%higher than that of T3 treatment,but the water use efficiency and irrigation water use efficiency of T3 treatment were 83.80%and 52.63%higher than that of CK treatment,respectively,and there was no significant difference in the yield between the two treatments（P<0.05）,but there were significant differences in the water use efficiency and irrigation water use efficiency between the two treatments（P<0.05）.Therefore,from the perspective of water-saving irrigation and economic benefits,T3 treatment is more suitable for local irrigation.（5）By monitoring and analyzing the quality indexes of jujube under different irrigation treatments,it was found that under the experimental conditions,the soluble solid content of T1 treatment with the highest soluble solid content was 28.27%,which was 0.94 percentage point higher than that of CK treatment（27.33%）,However,there was no significant difference among the treatments;Under the experimental conditions,there was no significant difference in the total sugar content among the treatments.The increase of irrigation amount would slightly reduce the total sugar content of jujube,but this effect was not significant;Under the experimental conditions,the increase of irrigation amount will slightly increase the total acid content of jujube,reduce the sugar acid ratio,but this effect is not significant.Through the analysis of comprehensive benefit evaluation,the order of comprehensive benefit evaluation of each irrigation treatment is T3 treatment,T2treatment,T1 treatment and CK treatment.From the perspective of water-saving irrigation and improving comprehensive benefits,T3 is the most suitable irrigation treatment for Minqin.To sum up,the suitable irrigation treatment for Minqin local arid area was T3treatment,that is,under drip irrigation mode,the whole growth period was irrigated for 9 times,including 1 time at Germination and leaf development stage,3 times at flowering and fruit setting stage,4 times at fruit expansion stage and 1 time at fruit maturity stage,with irrigation quota of 45mm.Under this irrigation mode,the yield is higher,the water use efficiency is the highest,and it will not affect the quality of jujube.The comprehensive benefit evaluation of jujube is the highest.It is not recommended to use furrow irrigation method with larger irrigation quota to irrigate jujube.