Pulsing of Plant-available Moisture & Nitrogen in Great Basin Communities: Interactions of Microbial Processes, Root Depth Distributions and Hydraulic Lift

提案#：DEB-9807097调查员(S)：考德威尔研究所：犹他州州立大学本提案的目的是研究大流域生态系统中不同生活型的植物和土壤微生物对土壤水分和氮素脉动的反应和影响。设在犹他州立大学的5名首席研究人员具有从微生物学到遥感的专业知识，他们从不同的角度和规模制定了以这些问题为重点的综合研究设计。水力抬升的作用(即深层吸水和夜间释放到表层土壤中)作为一种过程，在面对时间变化的情况下，可能对促进水和氮的获取特别重要。其他重点包括研究根分布的重要性，研究在不同环境中调节N有效性的微生物过程，以及不同植物生命形式的作用。尽管这项研究是以大盆地生物群为背景的，但这些主题与包括农业系统在内的几乎所有陆地生态系统有关，而且对陆地生态系统对全球环境变化的反应也有明显的影响。这项工作对流域水文和人类操纵大流域植被也有相当大的意义。

ABSTRACT PROPOSAL # : DEB-9807097 INVESTIGATOR(S) : CALDWELL INSTITUTION: UTAH STATE UNIVERSITY The aims of this proposal are to investigate how plants of different life forms and soil microbes react to and influence soil moisture and nitrogen pulses in a Great Basin ecosystem. Based at Utah State University, 5 principal investigators with expertise ranging from microbiology to remote sensing have developed an integrated research design focused on these issues from different perspectives and scales. The role of hydraulic lift (i.e., water absorption at depth and nocturnal release into upper soil layers) is featured, as a process that may be particularly important in facilitating acquisition of both water and N in the face of temporal variability. Other emphases include research on the significance of root distributions, on microbial processes that mediate N availability in variable environments, and on the role of different plant life forms. Although the study is set in the Great Basin biome, these topics are relevant to almost all terrestrial ecosystems including agricultural systems, and there are also clear implications for response of terrestrial ecosystems to global environmental change. The work also has considerable impor6t for watershed hydrology and human manipulation of vegetation in the Great Basin.