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.
