Effcets Of Mulching And Deficit Irrigation On Water Consumption Pattern And Growth Of The Pear-Jujube Tree

Water is the essential factor in development of agriculture, facing the agriculturalproduction of water scarcity in arid and semi-arid region of Northwest China,and many citiesand counties use fruits of economic development with characteristics as the point of economicgrowth, the paper studied the pear jujube tree that cultivated widely in shaanxi, used thebarrels planted under the canopy, focused on the Situation that covered by plastic film andstraw, the effect of water law of trees and the influence of the growth of trees of differentamount of irrigation water. Some main achievements obtained as follows:(1) In winter and spring, the temprature was low, the trees were in their sprouting-leafunfolding stage, solar radiation absorbed by the soil surface of the plastic film allows more tothe deep. The temperature increase in the four soil depths moisture at the same time of keepsoil moisture, and the germination of tree was advanced; in another key period of thepear-jujube tree—fruit enlargement stage, the insulation measures has lost its originalmeaning,but required the right temperature under the cover measures. The plastic mulchingstill plays the role of the soil "warming", and the straw mulching made the soil temperaturelower, it played the role of the soil "coolers".(2) The relationship of the water consumption rate between the different coveragetreatment was no cover﹥straw mulching﹥plastic mulching. Looking at the waterconsumption of the whole growth periods, plastic mulching and straw mulching processingwater than the CK were44.6%and33.5%. The relationship of the proportion of differentgrowth periods of water accounted for the whole growth period was the fruit enlargementstage﹥flowering-fruit setting stage﹥fruit ripening stage﹥sprouting-leaf unfolding stage.Sprouting-leaf unfolding stage and early of flowering-fruit setting stage, Soil surfaceevaporation was the main way of loss water. Late stage of flowering-fruit setting, fruitenlargement stage and fruit ripening stage, tree transpiration was the main way of loss water.In the water critical period and sensitive period of pear-jujube(late stage of flowering-fruitsetting and fruit enlargement stage), loss of water irrigation can not make the water to receivetimely supplement, so we should not take excessive loss of water irrigation for regulation. Thecovering reduced the water loss, it was more or less between the two kinds of covering; in thestage of water was not sensitive, we can increase the regulation of loss of water, so it can play a role in reducing transpiration and enhance post-compensation. And we should take thecovering measures to keep soil moisture, increase water use efficiency, achieve the purpose ofsaving water.(3) The sprouting-leaf unfolding stage was rapid growth period of the new branch andthe panicle. Under the water deficit equally, the two kinds of covering contributed to growthof the new branch and the panicle. Loss of water and covering affected the pear-jujube treeenter flowering time, water deficit and covering both can make flowering time early, thetreatment of covering under loss water make flowering stage7d in advance. Theflowering-fruit setting stage was another important stage of ecological indicators of thepear-jujube tree. The characteristics of the new branch and the panicle growth were same withthe previous growth stage. The fruit enlargement stage and the fruit ripening stage wereimportant stages of increase production and improve fruit quality, in the two stages, thegrowth of the new branch and the panicle were almost stagnantly, differences were notsignificant between the treatments.(4) Under different irrigation conditions, no matter what kind of coverage the way, thenet photosynthetic rate, Transpiration rate, Stomatal conductance and Intercellular CO2concentration were all showed that water deficit treatments＜Full irrigation treatments. Underdifferent covering conditions, in different time periods, different indicators showed differentsize relationship, but four indicators of photosynthetic characteristics of straw mulchingwere the maximum.(5) About the material of resilience PRO and MDA in the leaves, the water deficit causedadversity no matter what kind of covering, and was a very significant difference. But strawmulch ing alleviate the adversity caused by the water deficit. Relative to the no covering andthe straw cover, the two physiological indicators of Plastic treatement were high. Plasticcovering can be the equivalent of environmental stress. This may be relevanted with plasticcovering continued to play the role of "warming up", the plastic resulted in a high temperaturestress on the plant. The straw cover can alleviate the environmental stress caused by waterdeficit.