Effects of Earthworms on Nitrogen Cycling Processes and Decomposer Community Structure in Organic-based and Conventional Agroecosystems

蚯蚓对有机农业生态系统和传统农业生态系统中氮循环过程和分解者群落结构的影响

• 批准号: 9020461
• 负责人: Benjamin Stinner
• 金额: $ 55.55万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-02-01 至 1996-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9020461&HistoricalAwards=false
• 关键词: Effects; Earthworms; Nitrogen; Cycling; Processes

Earthworms affect many basic soil processes, but the overall impact of these important invertebrates on ecosystem-level processes are poorly understood. Drs. Stinner, Blair and Edwards suggest that earthworms are key organisms affecting the structure and function of decomposer communities and soil processes in many terrestrial ecosystems, including agroecosystems. This research examines the importance of earthworms as regulators of decomposer community structure, organic matter decomposition and N cycling in agroecosystems based on organic or inorganic sources of nutrients. Earthworm populations in field enclosures will be manipulated in three experimental agroecosystems where N is supplied primarily as i) legume-derived N, ii) animal manure N, or iii) inorganic fertilizer. Organic matter decomposition and N cycling processes will be used as integrating variables to assess the effects of earthworm activity on agroecosystem function. The following effects will be quantified: a) soil microbial numbers and activity, b) populations of other soil invertebrates, c) organic matter decomposition and changes in soil organic matter fractions, d) soil physical characteristics, e) partitions of N into selected above- and below-ground pools (plant biomass N, litter N, SOM , active (microbial) soil N, slow/passive soil N, extractable soil N); and f) rates and patterns of release of N from 15N-labelled plant residues, recovery in selected soil pools and plant uptake of N. This approach provides a unique, holistic perspective of the importance of earthworms in affecting ecosystem-level processes. Examining the effects of earthworms in systems based on organic inputs or inorganic N will provide data on the relative impact of earthworms in systems under different degrees of C or N limitation. Analysis of the interactive effects of earthworms and organic matter inputs on soil biota and processes will provide new insights into the basic mechanisms affecting N use efficiency and conservation in terrestrial ecosystems in general. The research will also contribute greatly to an understanding of regulation by earthworms of N dynamics in both organic N-based agroecosystems and conventional inorganically fertilized agroecosystems. The support and facilities for this research are outstanding.

蚯蚓影响许多基本的土壤过程，但这些重要的无脊椎动物对生态系统水平过程的总体影响知之甚少。斯坦纳、布莱尔和爱德华兹博士认为，蚯蚓是影响包括农业生态系统在内的许多陆地生态系统中分解者群落和土壤过程的结构和功能的关键生物。本研究探讨了蚯蚓在有机或无机养分来源的农业生态系统中作为分解者群落结构、有机质分解和N循环的调节者的重要性。农田围栏内的蚯蚓种群将在三个试验性农业生态系统中进行控制，在这三个生态系统中，N主要作为i)豆类来源的N、ii)动物粪便N或III)无机肥料供应。以有机质分解和氮素循环过程为综合变量，评价蚯蚓活动对农业生态系统功能的影响。以下影响将被量化：a)土壤微生物数量和活性，b)其他土壤无脊椎动物种群，c)有机质分解和土壤有机质组分的变化，d)土壤物理特性，e)N分配到选定的地上和地下池(植物生物量N，凋落物N，SOM，活性(微生物)土壤N，慢/被动土壤N、可提取土壤N)；和f)从15N标记的植物残留物中释放N的速率和模式、选定土壤池的恢复和植物对N的吸收。这种方法提供了一种独特的、全面的视角，说明蚯蚓在影响生态系统一级过程中的重要性。研究以有机投入或无机氮为基础的系统中蚯蚓的影响，将提供在不同程度的C或N限制下，蚯蚓在系统中的相对影响的数据。分析蚯蚓和有机质输入对土壤生物群和过程的交互作用，将对影响陆地生态系统氮素利用效率和保护的基本机制提供新的见解。这项研究还将有助于了解蚯蚓对有机氮基农业生态系统和常规无机肥料农业生态系统中氮素动态的调控。这项研究的支持和设施都很出色。