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Accueil du site → Doctorat → États-Unis → 1994 → Stemflow, throughfall, and root water channelization by three arid land shrubs in southern New Mexico

New Mexico State University (1994)

Stemflow, throughfall, and root water channelization by three arid land shrubs in southern New Mexico

Martinez-Meza, Ernesto

Titre : Stemflow, throughfall, and root water channelization by three arid land shrubs in southern New Mexico

Auteur : Martinez-Meza, Ernesto

Université de soutenance : New Mexico State University

Grade : Doctor of Philosophy (PhD) 1994

Three experiments were conducted to examine how precipitation-vegetation relationships for the shrubs Larrea tridentata, Prosopis glandulosa, and Flourensia cernua affect the interception, redistribution, and storage of water in desert ecosystem. The first experiment was designed to determine the percentage of rainfall partitioned as stemflow and throughfall, and also to evaluate the effect of some plant canopy parameters on stemflow and throughfall. The second examined the effect of stem-angles on stemflow. The third assessed the effect of varying canopy areas and volumes as well as root allocation on redistribution of stemflow into the soil profile. Differences in stemflow as percentage of precipitation were found among species. The stepwise regression analysis suggested that the best one-variable model for L. tridentata was canopy volume, which accounted for 87% of the variation in collected stemflow. The best one-variable model for P. glandulosa and F. cernua was canopy area, which accounted for 82% of the variation in collected stemflow in each species. Stemflow data from winter and summer months were statistically compared to determine the influence of leaves on stemflow generation in P. glandulosa and F. cernua. Stemflow amounts collected during winter months do not differ significantly from those of summer months. This suggests that in these species the absence of leaves during winter months does not affect the generation of stemflow. Analysis of variance showed that the percentage of throughfall was different among species. This suggested that the variations in canopy characteristics could explain, in part, the interspecific throughfall differences. Stem-angle and stem-length were shown to have a significant effect on stemflow generation in F. cernua and in L. tridentata. Similarly, there was a significant relationship between stem-angle and stemflow in P. glandulosa. The variability in morphology of L. tridentata in various topographic locations and soil types may be related to the importance of stemflow water to the shrub in any particular site. Analysis of Rhodamine-B dye distribution under shrubs indicated that root channels are preferential pathways for movement of stemflow water into soil, and that this water is potentially the source of soil moisture which allows shrubs to persist and even prosper under drought conditions.

Sujets : dissertation, dissertations, Flourensia, stemflow, Flourensia, throughfall, Flourensia,root water channeling, hydrology, root water, Larrea, stemflow, Larrea, throughfall, Larrea,root water channeling, Prosopis, stemflow, Prosopis, throughfall, Prosopis,root water channeling, shrub, stemflow, shrub, throughfall, stemflow, shrub, theses, thesis, throughfall, shrub


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