Effects Of Straw Returning And Pruning Compost On The Soil Characteristic And Fruit Quality In Pear Orchard

Straw returning and pruning compost are two effeicient way to make use of the agricultural waste.It is in great significance not only in the improvement of ecological environment but also in raising soil fertility.In this study,field experiments were carried out in different pear orchards to investigate the effects of straw returning and pruning compost on the content of soil nutrients,microbiological characteristic and fruit quality.The main results are as follows:1.Field experiment I were carried out in pear orchards in Chunjiang town and Mada mount of Changzhou city,including straw mulching(SM),pruning mulching(PM)and straw reactor(SR).It was found that the yield of SM and PM treatments were 37.4%and 40.6%higher than that of control,respectively.An increase of soluble sugar content in fruit were found in the SM and PM treatments,which was in accordance with a decrease of titratable acid content in fruit of SM and PM.The changes of soluble sugar content and titratable acid content resulted in a higher ratio of sugar to acid by 34.2%and 43%as compared to the control.In addition to an increase of yield by 35%than the control,the quality index of fruit was not significantly affected by the SR treatment.The content of soil dissolved organic carbon,available phosphorus,available potassium were found a significantly increas but a decrease in soil bulk density of these three application ways.Treatments of SM and PM led to the increment of 42.9%and 62.5%in the amount of soil fungi while SR treatment led to an increment of 116.5%in the amount of soil bacteria.The content of microbial biomass carbon and nitrogen in the soil of all treatments were improved significantly.2.Field experiment ? on different application amount of straw and decomposing bacterial manure was conducted in pear orchards in Xuebu town of Jingtan city at Jiangsu province for two consecutive years.Three treatments were include:straw mulching(S),straw mulching + decomposing bacterial manure(S+BM)and double straw mulching +decomposing bacterial manure(2S+BM).The results showed that after mulching 150 d,the decomposition rate of S-BM treatment were 62.4%(S-BM)and 50%(S and 2S-BM),respectively.Release rates of nitrogen and potassium of S-BM treatment was the highest after mulching 150 d.Straw mulching led to an increase of soil lowest temperature and a decrease of soil highest temperature,consequently,a reduction of temperature amplitude.The content of soil dissolved organic carbon was found to be improved while soil bulk density was decreased significantly in 2S-BM treatment.Straw mulching treatment increased the content of soil organic matter at 0?5 cm soil layer,and the content of soil available potassium at 0?5 cm soil layer of S and S-BM treatments was found a significantly increment.Nevertheless,2S-BM treatment led to an increase on the content of soil available nutrient for 0?15 cm soil layer.The amount of soil bacteria,fungi and the content of soil microbial biomass carbon and nitrogen of 2S-BM treatment were increased in the late growth stage of pear tree.In addition,the yield of 2S-BM,S-BM and S treatments were found to be 86.9%,17.8%and 28.7%higher than that of control,respectively.Straw mulching improved soil properties from the top down,and the effect of soil improvement by straw mulching was very obvious when the amount of returning straw are 45t·hm-2 in pear orchard.3.Field experiment ? was conducted on the 10 year old pear trees for three consecutive years to study the effects of pruning compost(PC)on the tree growth,fruit yield and quality,soil nutrients and microorganism with the control of chemical fertilizer(CF)and sheep manure(SM)based on equal nutrients and organic matter.It was showm that pruning compost could promote the increase of new shoot length and the content of leaf chlorophyll of pear tree,in compared with the chemical fertilizer treatment.It led to increases of pear yield by 47.3%and 31.7%as well as increases of single fruit weight by 3.3%and 11.9%in 2013 and 2014,respectively.The pear yield and single fruit weight of pruning compost treatment were 7.7%and 10%higher than that of sheep manure respectively.Application of pruning compost could increase the content of soil available iron and zinc,but the effect of sheep manure application on soil property was better.Sheep manure and pruning compost could significantly increase the soil microbial biomass and the contents of soil microbial biomass carbon and nitrogen.It was suggested that pruning compost was an effective way for the pruning reutilization to improve soil property and increase fruit yield.Appropriate straw and pruned branches returning ways should be choosed by the actual condition in the soil management process of pear orchard,to realize the unification of ecological and econimic performance.