Trophic interactions in the soil of rice-rice and rice-maize cropping systems

子项目3将调查从连续淹水水稻种植转向轮作（包括非淹水系统）和多样化作物对土壤动物群落和相关生态系统功能的影响。在洪水和非洪水系统中，将确定对土壤功能有重大影响的功能群，并将量化它们对不断变化的管理制度的反应以及作物轮作后的再定植能力。通过将土壤动物数据与SP4、SP5、SP7土壤服务数据以及本子项目（SP3）收集的数据进行对比，确定相应于特定功能群的土壤功能，即水坑层生物结构破坏、水分流失和养分淋失。除了直接从国际土壤研究所获得的实地数据外，还将建立涵盖未来气候条件下预期的更广泛环境条件的微观实验，以确定当地土壤动物主要成分的组成和功能稳稳性。食物网将基于现有的土壤动物数据进行建模，以全面了解i)水稻种植系统中生物群落的形成因素，以及ii)稻田土壤群落介导的碳和氮流。整合所有数据子集的物种-环境关系量化高级统计建模将具体说明水稻农业生态系统中作物多样化对土壤生物群和相关生态系统服务的影响。

Subproject 3 will investigate the effect of shifting from continuously flooded rice cropping to crop rotation (including non-flooded systems) and diversified crops on the soil fauna communities and associated ecosystem functions. In both flooded and non-flooded systems, functional groups with a major impact on soil functions will be identified and their response to changing management regimes as well as their re-colonization capability after crop rotation will be quantified. Soil functions corresponding to specific functional groups, i.e. biogenic structural damage of the puddle layer, water loss and nutrient leaching, will be determined by correlating soil fauna data with soil service data of SP4, SP5 and SP7 and with data collected within this subproject (SP3). In addition to the field data acquired directly at the IRRI, microcosm experiments covering the broader range of environmental conditions expected under future climate conditions will be set up to determine the compositional and functional robustness of major components of the local soil fauna. Food webs will be modeled based on the soil animal data available to gain a thorough understanding of i) the factors shaping biological communities in rice cropping systems, and ii) C- and N-flow mediated by soil communities in rice fields. Advanced statistical modeling for quantification of species – environment relationships integrating all data subsets will specify the impact of crop diversification in rice agro-ecosystems on soil biota and on the related ecosystem services.