Study On The Ridge-furrow Polypropylene Film Mulching Effects Of Rainfed Pear Orchard In Hilly And Gully Region Of Loess Plateau

Xixian,Shanxi Province is located in the hilly and gully region of the Loess Plateau,it is a pear high-quality production regions designated by the Ministry of Agriculture.However,due to lack of rainfall and irrigation water,the drought in this area is seriously,So it is difficult to guarantee yield and quality of pear.Scientifically and appropriate soil management model plays a key role in raising fruit yield and quality.Taking 18-year-old 'su pear'trees as test material,to study the effect of ridge-furrow polypropylene film mulching(RFM)on the dynamic changes in the moisture content,available nutrient,organic matter during the whole growth period in the hilly and gully region of Loess Plateau.The soil saturated hydraulic conductivity,soil bacterial community,pear root distribution,stem and leaf area specific conductance,chlorophyll content,gas exchange parameters,tree growth,fruit yield and quality were measured and detected.Main research results are as follows:(1)Compared with CK,RFM increased soil moisture content more throughout whole growth period,However,with pear growth and development,the difference in soil moisture content under CK and RFM gradually decreased;Compared with the field the soil moisture of pear orchard showed varying degrees deficit,the soil layer from 80 cm to 160 cm and 120 cm to 160 cm were water deficit in CK and RFM respectively;Compared with CK the RFM increased soil saturated hydraulic conductivity by 224.03%,Therefore,RFM is an effective agronomic measure to improve soil water infiltration and alleviate soil water deficit of pear orchards.(2)Under different mulching measures,at each sampling point,with the deepening of the soil Soil organic matter content is reduced.During the whole growth period,at different distances from the trunk,under RFM the average content of organic matter of all soil layers was lower than that of the CK.In topsoil,the available N of all sampling points was lower than that of other soil layers,that the difference is more Significant under RFM.Compared with the CK,In the 0-20 and 40-60 cm soil layers from the trunk,the average content of available N in the RFM is higher during the whole growth period.In the 40-60 cm soil layer,the average content of available P in the whole growth period was the lowest,and different management measures have no effect on it.Under RFM,the average content of available P is higher than that of the CK,in the 0-20 and 20-40 cm soil layer.During the whole growth period,the average content of available K in the RFM is lower than that of the CK.(3)Compared with CK,RFM increased soil bacterial diversity and predominance.Under different mulching measures,The top 3 dominant phyla of soil bacterial relative abundance,these were Proteobacteria,Actinobacteria and Gemmatimonadetes.The Proteobacteria relative abundance were significantly higher for RFM,while the Actinobacteria and Gemmatimonadetes was significantly lower than that of CK.Actinobacteria and Gemmatimonadetes play a key role in CK,The difference is that Deltaproteobacteria and Myxococcales are important for RFM.In addition,RFM improved soil bacterial community stability.(4)Under different mulching measures,there are some differences in the distribution of fine root(d?2 mm)of fruit trees in the horizontal distance 60?150 cm,vertical distance 0?60 cm away from trunk.The root length,root surface area and root volume for CK is higher than that of RFM in the soil layer from 20 cm to 40 cm.Under RFM,the root growth status of 0?20 cm and 40?60 cm soil layers is better than that of the CK.(5)The leaf area specific conductance,relative water content of the leaves and total chlorophyll content under RFM respectively increased by 34.71%,8.30%and 4.91%compared with CK.The result of gas exchange parameters showed that RFM could greatly increased the photosynthesis rate(Pn),stomatal conductance(Gs),transpiration rate(Tr)and water use efficiency(WUE)of pear leaves.Compared with CK,RFM increased the new-tip length,new-tip diameter,leaf area and dry weight of leaf by 26.89%?12.10%?8.5%and 17.11%.(6)Compared with CK,RFM significantly increased Vc content by 35%,fruit transverse diameter by 3.7%,fruit yield by 21.6%,but RFM decreased fruit soluble solids contents significantly.By contrast,titratable acid,solid acid ratio and hardness were not significantly different among treatments.