Influence of soil animals on C and N turnover in rice-based cropping systems

ICON子项目3研究管理多样化对稻基生态系统土壤动物结构和功能的影响。一个特别的重点是对塑造地下群落的行动者的透彻理解，以及土壤生物群对碳和氮流动的调解。SP3的一个基本假设是，具有高内在相互调节潜力的原生土壤动物的发展，极大地促进了洪水制度和作物改变的新水稻生产系统的可持续性。还将测试土壤动物的潜在危害。在ICON一期获得的SP3结果证明了土壤动物在水稻生态系统中的重要作用，但由于土壤群落仍处于演替的早期阶段，影响了深远的评价。因此，计划继续对这个问题进行调查。针对sp3， ICON第二阶段的具体目标是：(1)了解、预测和概括（跨地理梯度）水稻农业生态系统管理制度改变的演代变化和土壤无脊椎动物群落的建立（包括营养效应）；(2)通过实验量化土壤无脊椎动物通过生物扰动对生态过程的间接非营养效应；(3)评估土壤动物群在促进或降低国际图标缓解措施效率方面的潜力。SP3将严格遵守修改后的ICON框架，包括新的研究问题上的上下缩放。所有方法（野外调查和实验、中观实验、食物网建模、稳定同位素特征分析）都已建立，并将在必要时进一步发展。

ICON Subproject 3 studies the effect of management diversification on the structure and function of he fauna in the soil of rice-based ecosystems. A particular focus is on a thorough understanding of the actors shaping below-ground communities, and on the mediation of C- and N-flow by soil biota. A fundamental assumption of SP3 is that the development of a native soil fauna with a high inherent potential for interactive regulation significantly contributes to the sustainability of new rice production systems with altered flooding regimes and crops. Potential disservices of the soil fauna will also be tested. SP3 results gained during ICON Phase I prove the important role of the soil fauna in rice-based ecosystems, but the fact that the edaphic community was still in a very early stage of succession hampered far reaching evaluations. Investigations on this issue are thus planned to be continued. SP3-specific objectives for ICON Phase II are: (1) To understand, predict and generalize (across geographic gradients) successional changes and establishment of the soil invertebrate community in response to altered management regimes in rice-based agro-ecosystems (incl. trophic effects); (2) To experimentally quantify indirect, non-trophic effects of soil invertebrates on ecological processes via bioturbation; (3) To assess the potential of the edaphic fauna for facilitating or reducing the efficiency of the ICON mitigation measures. SP3 will strictly adhere to the modified ICON framework, incl. the new research question on up- and downscaling. All methods (field surveys and experiments, mesocosm experiments, food web modeling, analysis of stable isotope signatures) are established and will be further developed if necessary.