紫色土线虫对长期不同施肥措施的响应

Nematode response to long-term fertilization in purple soil

土壤线虫在农田生态系统中数量丰富且对土壤环境变化敏感,可用于评估不同田间管理条件下的土壤健康。本文探究了紫色土区长期不同施肥措施及土壤团聚体粒径对线虫群落的分布及其生态功能多样性的影响。试验设置了5个施肥处理:不施肥(对照,CK)、单施化肥(NPK)、生物炭+化肥(BCNPK)、商品猪粪+化肥(OMNPK)和秸秆+化肥(RSDNPK)。团聚体粒径分为:原状土(BS)、大团聚体(>2 mm;LA)和小团聚体(0.25–2 mm;SA)。结果表明,与对照相比,施肥可促进线虫数量增长,其中单施化肥处理下增幅最小(66%);有机物料与化肥配施对线虫数量的提升更为显著,秸秆+化肥处理下增幅达206%。不同施肥处理间线虫类群相对丰度差异显著,大小均表现为:食细菌线虫(BA)>杂食/捕食线虫(OP)>植食线虫(PP)>食真菌线虫(FU)。小团聚体较其他土壤团聚体的杂食/捕食线虫丰度更低,食细菌线虫丰度较高。秸秆与化肥配施处理下线虫群落结构指数和富集指数显著增加,且各施肥处理下线虫功能足迹呈现明显差异。有机肥与化肥配施(尤其是秸秆+化肥)可提高土壤养分供应且有利于形成稳定健康的土壤生态系统,助推区域农业的可持续发展。

Aims:Soil nematodes are abundant in agroecosystems and are sensitive to edaphic environmental changes,they can be used to assess soil health under different field management conditions.This study aims to investigate the effects of long-term fertilization and soil aggregation patterns on nematode community distribution and functional diversity in purple soil.Methods:Five fertilization treatments were established:no fertilizer(control,CK),chemical fertilizer alone(NPK),biochar+chemical fertilizer(BCNPK),commercial pig manure+chemical fertilizer(OMNPK)and straw+chemical fertilizer(RSDNPK).Soil particle sizes were categorized as:bulk soil,large macroaggregates(>2 mm)and small macroaggregates(0.25–2 mm).Results:Fertilization increased the number of soil nematodes compared to the CK with a minimum increase of 66%under the NPK treatment group.Soil treated with a combination of organic and chemical fertilizers exhibited an increase in nematode abundance of 206%.The relative abundance of nematode groups was consistent across treatments:bacterivores>omnivores/predators>plant parasites>fungivores.However,omnivores/predators and bacterivores populations in small macroaggregates were smaller and larger,respectively,than populations associated with other soil particle categories.Community structure and enrichment index values increased in the RSDNPK group,and the nematodes’functional footprint varied across treatments.Conclusions:The application of a combination of organic and chemical fertilizers(especially RSDNPK)can increase soil nutrient supply capacity and help establish stable and healthy soil ecosystems,supporting the development of sustainable local agriculture.