The Effect Of Different Muiching And Water Deficit On Pear Jujube

The northwest region in China is arid and little of rain, at the same time, and many counties in the district develop fruit trees planting as a means of economic growth, but the shortage of water resource restricts the development of fruit industry. Aim at this situation, this paper took the pear jujube widely grownn in this area as the research object, barrels plant under the canopy as the means, carrying out plastic film mulchiing and straw mulching and deficit in different growth stages,to explore soil water and heat conditions and the effect of mulching and deficit on growth and fruit quality, using principal component analysis(PCA) to analyze the comprehensive fruit quality under mulching and deficit,The conclusion included following several aspects:(1) Mulching and water deficit both could significantly increased soil temperature,At bud burst to leafing stage plastic film mulching and straw mulching had certain of warming effect,and soil temperature rose and dropped rapidly under film mulching, while the temperature changed slowly under straw mulching. Soil temperature gradually dropped and the time highest temperature appearing delayed with the increasing soil depth. Film mulching and straw mulching had remarkable influence on 10 cm soil layer and 5 cm layer respectively. At fruit growth stage the heat preservation of film mulching did harm to pear jujube, and straw mulching reduced soil temperature to prevent effectively the damage.(2) At bud burst to leafing stage water deficit could significantly inhibit the growth of branches, but the film mulching could relieve water stress. Mulching and deficit both could make the flowering ahead in different degrees, deficit under film mulching with the most significant effection. At Flowering to fruit stage new shoot and panicle grew more slowly, and the growth difference under mulching became smaller compared with control group, and at this stage straw mulching could mitigate the inhibitory effect of water deficit. Mulching could increase the flowering rate and fruit setting rate. Deficit at bud burst to leafing stage and re-water at flowering to fruit stage,which would improve flowering and fruit setting rate,but deficit at flowering to fruit stage would seriously affect the flowering and fruit setting rate.(3) When water was lack, chlorophyll content increased, and re-water also could increase the chlorophyll content, flower fruiting mulch is the highest chlorophyll content, and chlorophyll content under film mulching was the most at flowering to fruit set stage and the least at fruit growth stage. The chlorophyll content under straw mulching was least at bud burst to leafing stage and the most at fruit growth stage. Mulching means and water deficit as a single factor and interaction had significant influence on chlorophyll content at different growth periods.When water was lack, PRO and MDA content increased and then decreased after re-water. PRO and MDA content under film mulching was less than control group at bud burst to leafing stage and then increased at fruit growth stage. PRO and MDA content under straw mulching was more than film mulching but less than bare land,and decreased greatly at fruit growth stage. Mulching means and water deficit as a single factor and interaction had a significant impact on MDA content at each growth period.Stomatal conductance under film mulching was higher than other mulching treatments at bud burst to leafing stage and decreased at fruit growth stage. Stomatal conductance under straw mulching was the lowest at bud burst to leafing stage,but was higher than bare land and film mulching at other growth stages. Stomatal conductance significantly reduced with water deficit and increased significantly after re-water. Photosynthetic rate was highest under film mulching at bud burst to leafing stage, and photosynthetic rate under straw mulching was significantly higher than film mulching and bare land at middle and later periods, but the water use efficiency(WUE) dropped. Mulching and water deficit as a single factor and interaction had significant influence on WUE.(4) As to Fruit quality indicators, deficit under straw mulching had most significant promotion on hardness,soluble solids, vitamin C and soluble protein at bud burst to leafing stage. At flowering to fruit stage straw mulching could comprehensively improve the four indexes. At fruit growth and fruit maturation stages full irrigation under straw mulching could significantly improve the four indicators. Through principal component analysis, we found that the hardness, soluble solids, vitamin C and soluble protein could be important indexes of evaluating pear jujube fruit quality. After comprehensive evaluation, we found fruit quality improved with no yield reduction under the straw mulching and deficit at fruit maturation stage.