Role of soil texture on mesquite water relations and response to summer precipitation

Abstract

In the arid Southwest United States, monsoon precipitation plays a key role in ecosystem water balance and productivity. The sensitivity of deeply rooted plants to pulses of summer precipitation is, in part, controlled by the interaction between soil texture, precipitation intensity, and plant rooting depth and activity. In this study we evaluated the water relations of a leguminous tree species Prosopis velutina Woot. (velvet mesquite) occurring across three different aged soils varying in soil texture during two consecutive summers that substantially differed in the amount of monsoonal precipitation (1999 and 2000). We predicted that mesquite trees occurring on different textured geomorphic surfaces would be exposed to different levels of premonsoon water deficit and would not respond equally to summer precipitation. During both years, predawn and midday leaf water potentials were more negative on coarse textured soils than on medium and fine textured soils before the onset of the monsoon, indicating that plant water status is less favorable during drought on coarse-textured soils. However, leaf water potentials recovered rapidly on coarse-textured soils in response to monsoonal precipitation. These results suggest that mesquite sensitivity to future changes in winter and summer precipitation may not be uniform across the landscape, and that the interaction between precipitation and soil-plant hydraulic properties need to be better understood to realistically predict impacts of land cover change on ecosystem carbon and water balance.

Parent Publication

• Santa Rita Experimental Range: 100 years (1903 to 2003) of accomplishments and contributions; conference proceedings; 2003 October 30-November 1; Tucson, AZ

Citation

Fravolini, Alessandra; Hultine, Kevin R.; Koepke, Dan F.; Williams, David G. 2003. Role of soil texture on mesquite water relations and response to summer precipitation. In: McClaran, Mitchel P.; Ffolliott, Peter F.; Edminster, Carleton B., tech. coords. Santa Rita Experimental Range: 100 years (1903 to 2003) of accomplishments and contributions; conference proceedings; 2003 October 30-November 1; Tucson, AZ. Proc. RMRS-P-30. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 125-129.