控释肥残膜积累对土壤微生物群落组成的影响

Effects of controlled-release fertilizer residual coat accumulation on soil microbi-al communities

为探究控释肥残膜累积对土壤微生物群落的影响,采用Illumina MiSeq高通量测序技术,分析了不同控释肥残膜(聚氨酯)累积量下土壤细菌和真菌群落结构及多样性的差异。试验设不加聚氨酯残膜膜壳(CK)、添加聚氨酯残膜140 kg·hm^(−2)(CR1)、280 kg·hm^(−2)(CR2)、560 kg·hm^(−2)(CR3)和1400 kg·hm^(−2)(CR4)5个处理。结果表明:与CK相比,聚氨酯残膜施入土壤120 d后,CR4处理下土壤可溶性有机碳(DOC)、土壤含水量(SM)和玉米地下生物量(BGB)及CR3处理土壤NO_(3)^(−)-N含量显著增加(P<0.05),而土壤pH、速效钾(AK)、总氮(TN)、速效磷(AP)、NH_(4)^(+)-N含量无显著差异。聚氨酯残膜处理提高了细菌和真菌OTU(operational taxonomic unit)数量、细菌群落多样性(Shannon)和丰富度(Ace、Chao)指数,CR4处理与CK间差异显著(P<0.05),不同聚氨酯残膜处理下的土壤真菌群落多样性和丰富度无显著差异,但改变了基于门、属水平上的群落组成。随土壤聚氨酯残膜添加量的增加,变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)和伯克氏菌属(Burkholderia)相对丰度增加,而酸杆菌门(Acidobacteria)和鞘氨醇单胞菌属(Sphingomonas)相对丰度减少,CR4处理与CK相比差异显著(P<0.05)。与CK相比,聚氨酯残膜处理提高了子囊菌门(Ascomycota)相对丰度,CR3处理其相对丰度显著增加(P<0.05);聚氨酯残膜处理分别降低了球囊菌门(Glomeromycota),增加了被孢霉属(Mortierella)相对丰度,CR4处理与CK相比差异达显著水平(P<0.05)。Mantel检验结果显示,DOC对细菌群落结构的影响最大(P=0.003),AP、SM和BGB对细菌群落结构也具有显著影响(P<0.05)。真菌群落结构与土壤DOC、TN和SM呈现显著相关(P<0.05),其中DOC影响最大。由此,短期内聚氨酯残膜添加通过改变土壤可溶性有机碳、含水量、玉米根生物量等因子提高了细菌群落多样性,影响土壤细菌和真菌群落组成。

To explore the effect of controlled-release fertilizer residual coat accumulation on soil microbial communities,pot experiments were conducted with five treatments of 3.60–4.00 mm polyurethane addition(residues of controlled-release fertilizer coat),namely no residual coat(CK),140 kg∙hm^(−2) polyurethane addition(CR1),280 kg∙hm^(−2) polyurethane addition(CR2),560 kg∙hm^(−2) polyurethane addition(CR3),and 1400 kg∙hm^(−2) polyurethane addition(CR4).Illumina MiSeq high-throughput sequencing technology was used to analyze the differences in soil bacterial and fungal community composition and diversity under different treatments.The results revealed that the contents of soil dissolved organic carbon(DOC),soil moisture(SM),and belowground biomass of maize(BGB)in CR4 treatment and NO_(3)^(−)-N in CR3 treatment were significantly increased compared with those in CK;however,the soil pH and contents of available potassium,total nitrogen(TN),available phosphorus(AP),and NH_(4)^(+)-N did not significantly change in all treatments.The operational taxonomic units of bacteria and fungi,the diversity index(Shannon),and the richness indexes(Ace and Chao)of the soil bacterial community increased as the polyurethane addition rate increased,and the difference between CR4 and CK was significant;however,the diversity and richness indexes of the soil fungal community did not significantly change under different treatments.The relative abundance of the soil bacterial and fungal communities at the phylum and genus levels changed as the polyurethane residual coat increased.The relative abundance of Proteobacteria,Bacteroidetes,and Burkholderia increased with the accumulation of the residual coat;however,the relative abundance of Acidobacteria and Sphingomonas showed the opposite pattern,and the difference was significant between treatments CR4 and CK.Compared with CK,treatment CR3 improved the relative abundance of Ascomycota significantly,treatment CR4 increased the relative abundances of Glomeromycota and Mortierella significantly.The Mantel test showed that soil DOC,AP,SM,and maize BGB were the key factors affecting the bacterial community structure,whereas soil DOC,TN,and SM were the key factors affecting the fungal community structure.Therefore,polyurethane residual coat addition can directly or indirectly improve the diversity of bacterial communities and affect the composition of bacterial and fungal communities in the short term by changing the soil DOC,SM and maize BGB,and other factors.