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Nematode community structure and indicators of biologically-based fertility: Influence of management during transition to certified organic production.

机译：线虫群落结构和基于生物的繁殖力指标：向有机认证生产过渡期间管理的影响。

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摘要

This research investigated the influence of management on indicators of soil quality and nematode community structure in systems transitioning from conventional to organic production. The goal was to improve soil assessment and ultimately performance of organic production systems. Soil samples were collected from a trial with three transition pathways (pasture, row crop, and intensive vegetable production). Three amendment approaches (manure, compost and cover crops) were used within each transition. Standard soil testing showed use of organic practices increased concentrations of available P and K, Ca, Mg, pH, total organic C and N, soil C:N ratio and labile soil organic matter (SOM) fractions. Changes in SOM fractions were more noticeable than chemical indicators. Temporal data indicated that sampling before and after major tillage operations provides additional information about soil quality that is defined in terms of nutrient supply, habitat provision for soil organisms and prevention of environmental degradation. Soil resource concentrations fluctuated within season and were ranked: pasture>vegetable>row crop systems. Abundances of bacterial feeding nematodes were consistently associated with soil resource condition. Plant parasitic, predators and omnivorous nematodes were related with soil moisture and bulk density in a less consistent pattern. Nematode indicators, based on family taxonomic identification, were evaluated using standard and multi-date sampling during the certification year and found to be closely associated with soil resource indicators. When temporal dynamics were considered, the channel index (CI), plant parasitic index (PPI), enrichment index (EI), and structure index (SI), in that order, explained differences that resulted from three transition pathways. An EI>50 revealed soil nutrient enrichment in the pasture system. A CI>20 suggested the decay pathway was bacterially dominated in the spring following residue incorporation. A decrease in the SI and increase in the PPI after major tillage operations was the result of food web disruption. Overall, this study illustrated improvements in soil status that resulted from organic transition. Nematode-based indices were more sensitive to changes in soil quality than were SOM or chemical measures. Soil testing to optimize biologically-based fertility may require use of biotic indicators and sampling schemes that capture time-dependent dynamics associated with tillage or nutrient additions.
机译：本研究调查了管理对从传统生产向有机生产过渡的系统中土壤质量和线虫群落结构指标的影响。目的是改善土壤评估并最终改善有机生产系统的性能。从具有三个过渡途径（草场，大田作物和蔬菜集约化生产）的试验中收集土壤样品。在每个过渡期间使用了三种修正方法（肥料，堆肥和覆盖作物）。标准的土壤测试表明，采用有机做法增加了有效磷和钾，钙，镁，pH，总有机碳和氮，土壤碳与氮的比例以及不稳定的土壤有机质（SOM）的含量。 SOM分数的变化比化学指标更明显。时间数据表明，在主要耕作之前和之后进行的采样提供了有关土壤质量的其他信息，这些信息由养分供应，土壤生物的栖息地提供以及防止环境退化来定义。土壤资源浓度在季节内波动，并排序为：牧场>蔬菜>行作物系统。细菌摄食线虫的丰度始终与土壤资源状况相关。植物的寄生虫，捕食者和杂食性线虫与土壤水分和容重的关系不太一致。在认证年度期间，使用标准和多日期抽样对基于家庭分类学鉴定的线虫指标进行了评估，发现其与土壤资源指标密切相关。考虑时间动态时，通道指数（CI），植物寄生指数（PPI），富集指数（EI）和结构指数（SI）以此顺序解释了由三种过渡途径引起的差异。 EI> 50揭示了牧场系统中土壤养分的富集。 CI> 20表明，在残留物掺入后的春季，衰变途径是细菌主导的。大量耕作后SI下降，PPI上升是食物网破裂的结果。总的来说，这项研究说明了有机转变导致土壤状况的改善。基于线虫的指标比SOM或化学措施对土壤质量的变化更敏感。为了优化基于生物的肥力而进行的土壤测试可能需要使用生物指标和采样方案，以捕获与耕作或养分添加相关的时间相关动态。

著录项

  • 作者

    Ugarte, Carmen Marlene.;

  • 作者单位

    University of Illinois at Urbana-Champaign.;

  • 授予单位 University of Illinois at Urbana-Champaign.;
  • 学科 Agriculture Agronomy.;Agriculture Soil Science.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 184 p.
  • 总页数 184
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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