Study On The Impacts Of Different Pruning On Jujube Orchard Microenvironment And Yield And Quality Of Jujube Fruit

This research took the Jun-jujube of 5 years as testing materials which were distributed in Xinjiang Production and Construction Corps second division 34 regiment, and system studied the impacts of different pruning ways on three cultivation modes included the structural characteristics of jujube crown canopy, jujube orchard microenvironment(light, temperature, humidity) and fruit quality. The main results are as follows:(1) Winter pruning could determine the shape of trees, update the bearing branch groups, adjust the planting space of jujube orchard; summer pruning could affect canopy structure and further influence the growth and development of jujube. What’s more, through the following processes, such as, pinching, bud picking and trimming away branches, experiments showed that the jujube heads are reserved 4-5 pinching and secondary branches retained 5 pinching were best in summer pruning, in addition, jujube trees retained4-5 jujube heads were beneficial to balance the growth, and heavy pinching could promote the formation and growth of ligniform bearing branch.(2)Proper trimming could regulate the growth of jujube trees, and influence the tree volume and canopy structure the characteristics of canopy structure. The experimental study showed that: orchards pruning treatment of C could control tree height of 2.17 m, crown height 1.77 m, crown width 1.86 m × 2.7m, canopy spacing 1.94 m, so this pruning treatment was most conducive to saving efforts and carrying out mechanized operations. According to the results of the experiment, A treatment summer pruning was recommended that jujube heads should be reserved 3-4 pinching, secondary branches should be retained3-4 pinching and stress should be put on the heavy pinching as well as bud picking; B treatment summer pruning was suggested that jujube heads should be reserved 4-5 pinching, secondary branches should be retained 5-6 pinching and stress should be put on the bud picking; C treatment summer pruning was advised that jujube heads should be reserved 3-4 pinching, secondary branches should be retained 3-4pinching and stress should be put on the heavy pinching as well as bud picking either.(3) Pruning can change the microenvironment factors in jujube orchard. Jujube tree crown canopy light intensity distribution under C pruning treatment was significantly higher than that of A and B pruning treatments, and the worst light distribution was under B pruning treatment; in the vertical direction,the distribution of jujube tree canopy temperature and canopy height were positively correlated, the upper layer temperature was the largest and the lowest layer was the lowest, what’s more, in the horizontal direction, the temperature was negatively correlated with the distance from the center of the trunk, the temperature of the canopy periphery was the highest, the inner chamber temperature was the lowest, and the maximum temperature difference can reach 5 ℃-8.6 ℃; in addition, in the vertical direction, the distribution of jujube tree canopy jujube tree canopy was negatively correlated with canopy height, and from the lower part to the upper part of the canopy, the relative humidity gradually becomes smaller, further,in the horizontal direction, the smaller the distance from the center of the trunk, the greater the relative humidity was, in other words, the internal humidity was the largest, and the outside humidity was the smallest.(4) Pruning had significant impacts on the growth and development of jujube tree and its fruits. Jujube tree under C pruning treatment was significantly better than A and B pruning treatment on the growth and development of new branches, the growth of leaf area and the chlorophyll content. B pruning treatment hadmade jujube tree crown larger, branches disorder, the fruits which tree produced little and small, and average fruit weight only 11.74; A and C pruning treatments could make jujube tree’s structure become more reasonable, the number of jujube fruit per plant and average fruit weight larger, respectively 735 and1189.7, and the average fruit weight were 18.43 and 18.85, respectively. So both two pruning methods are conducive to high yield.(5) The influence of pruning on jujube fruit quality: judging from the appearance quality, jujube fruits which were under C pruning treatment had the best quality, average jujube fruit weight was great and reached 21.09 g, and its vertical and horizontal diameter were also big and were 48.04 mm and 32.63 mm,respectively, what’s more, its fruit flesh thickness was also thick and was 10.27 mm. From the intrinsic quality, the content of soluble sugar of jujube fruits which was under B pruning treatment was the highest and reached 24.48%, C pruning processing was the lowest and was 16.22%, however, the content of the soluble solids which was under C pruning treatment was also the highest and reached 31.04%,titratable acid content of jujube fruits was the lowest and was 0.72 %, and fruit- cracking rate of jujube fruits which was under A pruning treatment was the lowest, but the percentage of esculent part was the highest and reached 98%.(6) In the same pruning process of the canopy, the fruit quality of the upper layer was obviously superior to that of the lower layer. And there was a significant difference between the number of jujube fruit per plant and average fruit weight after they were under A, B and C three different treatments, the result was that the yield which was under C pruning treatment was the highest, but the yield which was under A pruning treatment was the lowest. In addition, there was no difference in external quality between the lignified and other unlignified jujube fruits after they were under A and C treatments. However, the intrinsic quality of jujube fruits which were under A pruning treatment was significantly better than that of C pruning treatment.(7) The water content of jujube fruits which were under C pruning treatment was the lowest and was21.82%, so it was beneficial to the storage and transportation of jujube fruits, however, the water content of jujube fruits which were under A pruning treatment was the highest and reached 28.21%, thus affected the storage and transportation of jujube fruits.