Amount and Distribution of Dry Matter, Nitrogen, and Organic Carbon in Soil-Plant Systems of Mesquite and Palo Verde

Abstract

Over a 3-year period, soil-plant systems of velvet mesquite and palo Verde from the Sonoran Desert were sampled by standing crop, litter, and soil components and analyzed to describe the amount and distribution of dry matter, nitrogen, and carbon in the systems. Honey mesquite was sampled on a limited basis in southern New Mexico. Velvet mesquite averaged about one-third larger in crown area and weight than palo Verde, but the two shrubs were similar in the distribution of dry matter, N, and C. Honey mesquite was much smaller and differed in distribution of dry matter, N, and C. Regression analysis showed that dry matter, N, and1 C in components of shrub systems of velvet mesquite and palo Verde varied in a predictable manner and can be estimated with good precision using height, average crown diameter, or crown area of shrubs as the independent variable. Functional analysis showed that soil under palo-Verde did not accumulate N or C-with increase lin shrub size, whereas that under velvet mesquite accumulated N :at the rate of 11.2 g/m* per meter of height and C at the rate of 0.11 kg/m* per meter of height. Shrubs dominate the vegetation on over 200 millialn hectares of land in the conterminous United States, mostly in the Southwest and the Intermountain Basin. Many authorities consider shrubs the climax vegetation on about one-half this area, while on the remaining 1'00 million hectares shrubs now dominate where grasses were once the climax dominants. Man has been using shrublands since prehistoric times, but until recently little management has been applied. When used, management usually has been directed at eliminating shrubs. Because shrubs play an important role in terrestrial ecosystems, we should understand their ecological role. This is especially important in arid areas where shrubs are an important component of the vegetation. This paper reports on a study to determine how dry matter, nitrogen, and carbon were accumulated and distributed in soil-plant systems of two desert shrubs: velvet mesquite (Prosopis juliflora) and palo verde (Cerdicium floridurn). Limited data on honey mesquite (Prosopis juliflora var. glandulosa) are included as an adjunct to the main study. Methods Study Locations The study area was located in the Upper Sonoran Desert approximately 32 km south of Tucson, Arizona, at the Santa Rita Experimental Range. The study site was on an alluvial plain with a slope of less than 5% and an elevation of 975 m. Numerous arroyos and small shallow washes dissect the upland areas. Sampling was conducted on the upland sites on the Sonoita soil series, a coarse, loamy, mixed, thermic family of Typic Haplargids derived from The authors are senior research ecologist,

Influence of mesquite (Prosopis glandulosa) on soil nitrogen and carbon development: Implications for global carbon sequestration

“…The hypothesis that Prosopis selectively occurs on islands of fertility and that the increased fertility is not created by active N-fixation (Garcia-Moya & McKell, 1970;Barth & Klemmedson, 1982) must be rejected for two reasons. First, the %Ndfa of wood and leaves, that is based on the ratios of naturally occurring isotopes, firmly "% Ndfa leaf; "% Ndfa wood; "% Ndfa leaf ; "% Ndfa wood.…”

“…The pumping of nutrients from deeper levels in the soil profile has been used to explain the increased soil fertility beneath the canopies of N fixing and non-N fixing trees (Barth & Klemmedson, 1982). Pumping of nutrients from deeper layers undoubtedly occurred to result in the increased soil P under large Prosopis canopies.…”

“…Despite the fact that trees such as Prosopis can fix N, some workers (Garcia-Moya & McKell, 1970;Barth & Klemmedson, 1982) have suggested that the increased nutrients under the canopies is simply a redistribution of nutrients from deeper in the profile and outside the canopy.…”

Mesquite and grass relationships at two spatial resolutions

“…These patterns reflect differences among grass species in their response to decreased soil moisture (Cable 1977) and an exponential increase of shade and soil nitrogen under large Prosopis velutina size (Barth and Klemmedson 1982;Tiedemann and Klemmedson 1986). Muhlenbergia porteri production was not sensitive to an 80% light reduction, Digitaria californica production declined sharply at >40% light reduction, and Bouteloua eriopoda (Torr.)…”

Spatial and temporal litterfall heterogeneity generated by woody species in the Central Monte desert

“…Among the mechanisms proposed to explain the nutrient enrichment of under-canopy soil is the contribution of organic matter in the form of litterfall, which entails redistribution of root-absorbed nutrients toward the area under cover (Barth and Klemmedson 1982;Tiedemann and Klemmedson 1972). Litterfall contribution, with the consequent litter accumulation, is the basis for the development of the decomposer chain and the reservoir of soil nutrients, and has been found to affect negatively the establishment of some species, through chemical or physical processes (Facelli and Pickett 1991a, b;Facelli et al 1999), or positively through soil moisture conservation in water-limited ecosystems (Pugnaire et al 1996a).…”