长期不同施肥模式对黄壤旱地土壤细菌群落结构和土壤养分的影响

Effects of long⁃term fertilization patterns on bacterial community structure and soil nutrients in dryland of yellow soil

明确黄壤旱地细菌群落对长期不同施肥的响应,可为今后建立科学的施肥制度和培育健康土壤提供理论依据。本研究依托进行了25年的黄壤长期定位施肥试验,采集不施肥(CK)、平衡施用氮磷钾化肥(NPK)、单施有机肥(M)、常量有机无机肥配施(MNPK)和1/2有机肥替代1/2化肥(MNP)处理0~20 cm土层土壤样品,采用Illumina MiSeq高通量测序技术研究了不同施肥模式对土壤细菌群落结构和土壤养分含量的影响,并探究土壤细菌群落的主要驱动因子。结果表明:与NPK处理相比,长期施用有机肥处理土壤pH和有机质含量分别显著提高了11.4%~13.5%和28.8%~52.0%。长期不同施肥模式并没有影响土壤细菌α多样性,但显著影响了细菌β多样性。与CK和NPK处理相比,M、MNP和MNPK处理显著改变了土壤细菌群落结构,浮霉菌门和匿杆菌门的相对丰度明显增加;与CK相比,4个施肥处理增加了拟杆菌门的相对丰度,降低了放线菌门和绿弯菌门的相对丰度。土壤pH是影响土壤细菌群落结构最关键的因子。施肥激发的稀有微生物类群(如浮霉菌门和匿杆菌门)对不同环境因子的变化敏感性更高,是形成群落多功能性的主要驱动力。综上,添加有机肥改善了土壤性质,提升了土壤肥力,显著改变了土壤细菌群落结构,有利于培育健康土壤。

Understanding the responses of soil bacterial community to long⁃term fertilization in dryland of yellow soil could provide theoretical basis for establishing scientific fertilization system and cultivating healthy soil.Based on a 25⁃year long⁃term fertilization experiment on yellow soil,we collected soil samples from 0-20 cm layer under different fertilization treatments:no fertilization(CK),balanced application of N,P and K fertilizers(NPK),single application of organic fertilizer(M),combined application of constant organic and inorganic fertilizer(MNPK),and 1/2 organic fertilizer instead of 1/2 chemical fertilizer(MNP).Illumina MiSeq high⁃throughput sequencing technology was used to examine the effects of different fertilization patterns on soil bacterial community structure and soil nutrient content.The main driving factors of soil bacterial community were explored.The results showed that soil pH and organic matter content under treatments with organic fertilizer increased by 11.4%-13.5%and 28.8%-52.0%,respectively,compared to that under NPK treatment.Long⁃term fertilization did not affect soil bacterialαdiversity,but significantly affected soil bacterialβdiversity.Compared with CK and NPK treatment,treatments of M,MNP,and MNPK significantly changed soil bacterial community structure,and increased the relative abundance of Fusobacteria and Anaerobes.Four fertilization treatments increased the relative abundance of Bacteroidetes,and decreased the relative abundance of Actinomyces and Campylobacter,compared to CK.Soil pH was the most important factor affecting soil bacterial community structure.Fertilization⁃stimulated rare microbial taxa(Pumilomyces and Anaerobes)were more sensitive to changes in different environmental factors and were the main drivers of the formation of community versatility.In conclusion,organic fertilizer improved soil properties and fertility and changed soil bacterial community structure,which are conducive to cultivating healthy soil.