Effects Of Water-saving Type Pruning Techinques On Soil Moisture And Growth In Rainfed Jujube Forest

The Loess Plateau drought and rain,soil erosion is serious.The large area of returning farmland to forest has worsened the soil moisture environment in this area,and the phenomenon of soil dry layer has appeared.Scientific and rational use of local water resources to solve the problem of soil drying layer has become the focus of many scholars,and it is a great significance to the sustainable development to local ecology.In this study,water-saving pruning techniques were applied to jujube forest under rainfed condition.Four different initial soil volumetric water content levels were set for the experiment in the open air,analyze and evaluate the effect of water-saving pruning technology on jujube forest soil moisture.This experiment has important significance for the sustainable development of dry land jujube forest,and can be used for reference to solve the soil drying of forest land in the Loess Plateau.The main conclusions are as follows:(1)Observation the four kinds of initial soil moisture content was significant difference under the condition of natural precipitation.The results show that in the same external environment,with time prolonging,the soil water content of the four kinds of communities was approaching,and the area between from the beginning of the significant difference is not significant difference.Results showed that the soil moisture was tended to be a fixed value for different initial soil moisture contents under natural rainfall.And this value was depended on rainfall.Normal precipitation year soil moisture was steady at(13.83±0.22)% in 2014,partial drought year soil moisture was steady at(9.46 ±0.32)% in 2015.(2)The effect of different initial moisture content on the length of bearing branchlet and the coarseness of bearing branch of the four plots was the same.The high initial soil moisture content was beneficial to the length of bearing branchlet and the growth of jujube coarseness.The initial soil moisture had no significant influence on the size and weight of jujube fruit,but had significant influence on the number of fruits,and there was a significant difference in the number of fruits,and the initial soil moisture content is high and the number of the fruit is more.Different initial soil moisture will affect jujube fruit yield by controlling the number of fruits.In 2014,the initial moisture content of 1 and 2 areas yield were as high as 18753 kg·hm-2,12434.3 kg·hm-2,even if the lowest 4 area soil moisture conditions still can get 6750 kg·hm-2 output.This yield is equivalent to 1.5 times the yield of the local jujube forest.The results show that the application of fine water-saving pruning method has important value in increasing yield of local jujube forest,and it also shows that there is still great potential for jujube production in semiarid area with insufficient rainfall.(3)In 2014,the different initial soil moisture content had a significant effect on biomass.The initial soil moisture content is small and the biomass is less.In the early 2015,the soil moisture difference between the 4 plots was small.That is,the biomass of the four plots had no significant difference.It showed that when the soil moisture was not different,the precipitation determined the growth of the jujube tree,and the biomass approached.In 2014,the difference of jujube growth was mainly determined by initial water content.The lack of soil moisture in spring will still affect the growth of jujube trees and cause obvious growth differences.(4)In the semi-arid loess hilly area of low rainfall,adopting water-saving pruning technique is an effective way to improve the water efficiency of jujube tree.Comparison of water saving pruning jujube trees and field jujube trees,in 2014,the water use efficiency increased by more than 4.5 times.Water use efficiency could be increased by more than 3.6 times in 2015.It proves that water-saving pruning technology has good application value in production.The study provides a new basis for maintaining the dynamic balance of soil moisture and realizing sustainable development.