Effects On Soil Properties, Pear Tree Growth, Fruit Quality By Soil Management Method

Orchard soil management model plays a key role in raising fruit yield and quality. Three different kinds of soil management methods were designed, which included inter-planting white clover (T1), plastic mulching (T2) and cleaning tillage (CK), to reflect of the influence of soil managements on the soil properties, root characteristics, tree growth and fruit yield and quality in pear orchard, the soil physical properties, soil nutrients, the quantities of the soil bacteria, fungi, actinomycete, soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN), pear root distribution, tree growth and fruit yield and quality were detected and analyzed. Results were as follows:1. Compared to cleaning tillage, inter-planting white clover could reduce soil temperature, in contrast, plastic mulching could increased soil temperature. Practiced the inter-planting white clover and plastic mulching in pear orchard could slow down the evapotranspiration of soil water, enhanced soil water retaining capacity, thus enhanced soil moisture content.the soil bulk density were reduced and the soil porosity were increased in Inter-planting white clover and plastic mulching.2. The soil chemical properties of orchard had been changed obviously after inter-planting white clover and plastic mulching. Compared with clean tillage, inter-planting white clover significantly increased soil organic matter by5.5%, and available phosphorus by9.7%; but the effects of plastic mulching on the contents of soil total nitrogen, available phosphorus and available potassium were not obvious. Compared with cleaning tillage, inter-planting white clover and plastic mulching significantly increased the content of soil changeable Ca by9.6%and7.3%; soil changeable Mg by16.4%and9.2%. The effect of inter-planting white clover on soil microelement content such as the content of Fe、Cu and Zn were obvious, but there was no significant effect on available Zn. Plastic mulching improved the content of Fe、Cu、Zn obviously, but there was no significant effect on available Mn.3. Microorganism quantity in pear orchard with inter-planting white clover and plastic mulching were higher than cleaning tillage.The amount of soil microorganisms in each growth period were higher in enlargement period and maturity period than that in young fruit period and falling period. Inter-planting white clover and plastic mulching could increase the content of soil microbial biomass carbon and nitrogen, in the same time, the content of soil microbial biomass carbon and nitrogen in enlargement period was highest and in falling period was lowest.4. Root dates were analyzed to study the root growth distribution of pear tree in the condition of soil management treatments by WINRHIZO analyzing software, the result showed that:the horizontal distribution of tree roots were mainly concentrated in the30-90cm, the vertical distribution were centralized in the20-60cm. The root length, root surface area and root volume for inter-planting white clover and plastic mulching were higher than that of control treatment. Within three soil management, in different diameter classes the root biomass of0～1mm was most,1-3mm was the second, the>3mm was least. The total length and surface area of root in inter-planting white clover treatment were largest, while the root volume was least.5. Inter-planting white clover significantly increased leaf area by13.2%, chlorophyll content by6.0%, shoot length by22.6%, but plastic mulching had no obvious effects on tree growth indicators. Compared to cleaning tillage, inter-planting white clover and plastic mulching could significantly improve the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and intercellular CO2concentration (Ci), with plastic mulching under the photosynthetic rate (Pn)、 transpiration rate (Tr), stomatal conductance (Gs) and intercellular CO2concentration (Ci) for plastic mulching were increased by21.1%、59.9%、82.4%,18.8%respectively. At the same time, inter-planting white clover significantly improved the content of leaf N、K, but had no significantly effects on the content of leaf P、Ca、 Mg and micro-element content; there was no obvious effect on leaf mineral contents with plastic mulching.6. Inter-planting white clover could significantly improve fruit weight, fruit yield, soluble solids,soluble sugar content and fruit mineral elements K、 Mg、B, but has no significantly effects on fruit shape index, firmness and titratable acid. Plastic mulching could obviously improve fruit weight and soluble solids, but the effects on fruit shape index, soluble sugar, titratable acid, fruit yield and fruit mineral elements were not significant.