短期梨树枝条覆盖还田对土壤理化性质和微生物群落的影响

Effects of short-term pear branches mulching on soil physical-chemical properties and microbial community structures

枝条还田不仅是废弃物资源化利用的有效途径,还是土壤综合肥力提升的重要措施。以‘金蜜’梨为研究对象,开展梨树枝条粉碎覆盖还田试验,共设置4个处理:不还田(0 kg/株,R0)、低量还田(4 kg/株,R4)、常规量还田(8 kg/株,R8)和高量还田(12 kg/株,R12)。在梨树枝条还田8个月后,采用常规分析方法和Illumina MiSeq高通量测序技术,研究土壤理化性质和微生物群落对不同枝条还田量的响应差异。结果表明:随着枝条还田量的增加,R4处理可以提高土壤粘粒含量,但R8、R12处理增加了砂粒含量;土壤微生物生物量碳、氮含量以R4处理最高,分别为123.82和34.04 mg/kg。枝条还田对土壤细菌多样性指数无显著影响,但增加了变形菌门的相对丰度、降低了绿弯菌门的相对丰度,并改变了细菌目水平上的优势类群。R4处理土壤真菌chao1指数显著高于其他处理,枝条还田显著增加了担子菌门的相对丰度、降低了子囊菌门的相对丰度,在真菌目水平上,枝条还田增加了伞菌目、粪壳菌目等类群的相对丰度,但降低了小子囊菌目的相对丰度。冗余分析结果显示,土壤富里酸、机械组成(粘粒和粉粒)是微生物群落组成存在差异的主要驱动因子。因此,在当前梨园枝条粉碎覆盖还田的条件下,结合土壤理化性质和微生物群落结构的变化,推荐短期内以4 kg/株为最佳枝条还田量。

Branches returning is not only an effective way of waste resource utilization,but also an important approach to improve soil comprehensive fertility.In the present study,a branches mulching experiment was conducted from 2017 to 2018 and the pear tree cultivar was‘Jinmi’pear.Four treatments were set up:no branches mulching at 0 kg/plant(R0),low branches mulching rate at 4 kg/plant(R4),conventional branches mulching rate at 8 kg/plant(R8)and high branches mulching rate at 12 kg/plant(R12).In order to study the effect of different branches mulching rate on soil physico-chemical properties and microbial community structures,the general analysis method and Illumina MiSeq highthroughput sequencing technology were adopted,after 8 months of the return of pear branches to the filed.The results showed:With the increasing branches mulching rate,R4 treatment improved soil clay content,R8 and R12 treatment improved soil sand content.The highest microbial biomass carbon and nitrogen were both obtained in R4 treatment,which were 123.82 and 34.04 mg/kg,respectively.Compared with R0,branches mulching(R4~R12)had no significant effect on bacterial diversity,but increased the relative abundance of Proteobacteria,and decreased Chloroflexi.Branches mulching altered the bacterial community structures at order level.For the fungi,R4 treatment had the highest chao1 index.At fungal phylum level,branches mulching(R4~R12)increased the relative abundance of Basidiomycota,but decreased the relative abundance of Ascomycota.At fungal order level,branches mulching increased the relative abundance of the relative abundance Agaricales and Sordariales,but decreased Microascales.The redundancy analysis showed that soil fulvic acid and mechanical composition(clay and silt)were the main environmental driving factors.Therefore,under the current condition of pear branches mulching,considering the changes in soil physico-chemical properties and microbial community structures,the optimal branches mulching rate in the short-term was 4 kg/plant.