长期施用不同肥料对橘园土壤生物群落结构的影响

Effects of long-term application of different fertilizers on soil biota community composition in citrus orchards

为探讨长期施用不同肥料对橘园土壤生物群落结构的影响,于2019年7月采集连续单施化肥、厩肥+化肥和单施生物有机肥10~12年的橘园土壤,并对土壤中的微生物、线虫、螨和蚯蚓的群落结构进行分析。结果表明:与单施化肥(F)处理相比,厩肥+化肥(M)和单施生物有机肥(O)处理均提高了土壤微生物生物量碳,并提高了细菌/真菌比例,表明肥料碳主要通过快速的细菌通道在生物群落内进行周转;共鉴定得到土壤线虫664条,F、M和O处理的线虫密度分别为每100 g干土188、163条和293条。与F相比,M和O处理显著提高了食细菌线虫的数量(P<0.05),另外,O处理显著提高了植物寄生线虫的数量(P<0.05);共捕获土壤螨46523只,F、M和O处理中螨的密度分别为19548、19195只∙m^(-2)和7483只∙m^(-2)。与F处理相比,M和O处理的螨总数下降,但捕食性螨数量上升,表明土壤生物活性提高;共分离得到蚯蚓80条,F、M和O处理中的蚯蚓密度分别为11、37条∙m^(-2)和33条∙m^(-2)。M和O处理中的蚯蚓数量及群落多样性显著高于F处理(P<0.05),蚯蚓数量和多样性的提高有利于促进物质分解和维持生态系统的稳定。研究表明,与单施化肥相比,长期施用有机肥改变了橘园土壤生物群落结构,总体上促使土壤生物群落结构向有利于土壤养分循环和生态系统稳定的方向发展。

To study the effects of long-term application of different fertilizers on soil biota community,soil samples were collected in July 2019 from three citrus orchards,which were subjected to chemical fertilizer(F),animal manure+chemical fertilizer(M),or biological organic fertilizer(O)for 10~12 years,respectively.The community composition of soil microbes,nematodes,mites,and earthworms was analyzed.In comparison to treatment F,treatments M and O increased soil microbial biomass carbon and increased the ratio of bacteria/fungi,which indicated that the turnover of fertilizer-derived carbon in the biological community was dominated by rapid bacterial channels.In total,664 soil nematodes were identified in this study.The density of nematodes for F,M,and O treatments was 188,163,and 293 per 100 g dry soil,respectively.The numbers of bacterial feeding nematodes in the two organic treatments significantly increased compared with the chemical fertilizer treatment.Additionally,the number of plant parasitic nematodes in treatment O significantly increased(P<0.05).In total,46,523 soil mites were collected during the research.The density of mites for F,M,and O treatments was 19548,19195,and 7483 per square meter,respectively.Treatments M and O showed lower number of mites,but higher number of predatory mites than treatment F.The increase in predatory mites reflected enhanced biological activity.In this study,80 earthworms were isolated.The density of earthworms for F,M,and O treatments was 11,37,and 33 per square meter,respectively.Treatments M and O showed a significant higher number and community diversity of earthworms than treatment F(P<0.05).Increase in earthworm density and diversity not only promotes the decomposition of organic matter,but also maintains the stability of the ecosystem.Our results indicated that long-term application of organic fertilizers changed the community composition of soil biota in citrus orchards,which enhanced the effect of soil biota on promoting a healthy soil nutrient cycle and maintaining the ecosystem stability.