Effects Of Mist Irrigation During The Flowering Fruiting Setting Period On The Growth,Yield And Quality Of Jujube Trees

The high temperature and low humidity environment in the canopy of jujube trees during the flowering and fruiting period in the southern Xinjiang region has a significant impact on the growth,yield,and quality of jujube trees.In order to explore the improvement of the canopy environment of jujube orchards through mist irrigation during the flowering and fruiting period,promote the physiological growth of jujube trees,and improve fruit yield and quality,this article takes the southern Xinjiang Jun jujube as the research object.Indirect underground drip irrigation is used throughout the entire growth period,and mist irrigation is carried out during the flowering and fruiting period.Two experimental factors were set for the experiment,namely the duration of mist irrigation and the amount of indirect subsurface drip irrigation.Three levels were set:the duration of mist irrigation was 20 minutes（T1）,40 minutes（T2）,and 60 minutes（T3）each time,three times a day,at 11:30,15:30,and 19:30,respectively;The three levels of indirect subsurface drip irrigation water volume treatments were 24 L/plant·time（D1）,27 L/plant·time（D2）,and 33 L/plant·time（D3）,respectively.The entire experiment consisted of 9 treatments and a control treatment（CK）with only 27L/plant per root zone irrigation,totaling 10 treatments.During the experiment,indicators such as canopy air temperature and humidity,soil evaporation between trees,relative abundance of microorganisms,shallow soil aggregates,physiological growth of fruit trees,and fruit yield and quality were detected.Finally,TOPSIS was used to comprehensively analyze the fruit yield and quality of different treatments.The test results indicate that:（1）Mist irrigation can help improve the microclimate of jujube orchards and enhance various soil characteristics.During the dense fog irrigation period,the average air temperature of T3 significantly decreased by 5.9%compared to CK,and the average relative humidity of T2 significantly increased by 6.7%compared to CK.Fog irrigation inhibited soil evaporation between trees,and T1,T2,and daily average soil evaporation significantly decreased by 5.5%and 7.56%compared with CK.T2 treatment has an inhibitory effect on ascomycetes and a great promoting effect on beneficial fungi such as Fusarium globosum.Other beneficial dominant bacteria such as acidobacterium,blastomonas,and nitrifying spirochetes increase in relative abundance with the increase of fog time.The treatment of applying mist irrigation significantly increased the stability indicators of soil aggregates,with the highest values of each indicator under the T2D3treatment.（2）Mist irrigation helps promote the growth of jujube trees.Under the same root zone irrigation amount,with the increase of mist irrigation duration,the diameter diameter of jujube trees showed a trend of first increasing and then decreasing,and under the same mist irrigation duration,the diameter diameter diameter increased with the increase of root zone irrigation amount;With the increase of mist irrigation duration and root zone irrigation amount,the chlorophyll content of leaves is effectively improved.Under the same irrigation amount,the net photosynthetic rate significantly increased with the increase of mist irrigation duration,and T3D2 increased by 5.74 compared to CKμmol·CO₂·m²·s^-1.（3）Mist irrigation can help improve the yield and quality of Junjubes.Three times a day of 40 minute mist irrigation is beneficial for fruit enlargement,and the average vertical and horizontal expansion rates under T2D3 treatment are the highest,with 0.559 mm/d and 0.434 mm/d,respectively,which are 15.32%and 19.52%higher than CK;The maximum vertical and horizontal diameters of the fruit under this treatment are 47.38mm and 33.13 mm,respectively.However,as the duration of mist irrigation increases,the rate of fruit expansion decreases.Three times a day of 20 minute mist irrigation is beneficial for improving yield,with the highest yield per mu under T1D3 treatment,significantly increasing by 35.85%compared to CK.With the increase of misting time,the content of soluble sugar and soluble protein in fruit quality increased,while the content of titratable acid decreased.By using TOPSIS for comprehensive evaluation of yield and quality,it was found that good quality and yield can be achieved through 40 minute mist irrigation three times a day during the flowering and fruiting period,with a water volume of L/plant·time.