Biogeochemistry of C, N, and P in a Soil Catena of the Shortgrass Steppe

Abstract

Measurements of carbon, nitrogen, and phosphorus content were carried out in the soils of a hillslope of shortgrass steppe. Plant biomass, soil morphology, and soil physical properties were also measured. Soil morphology indicated that the site had undergone several cycles of rapid erosion and deposition. Total mass of C, N, and P increased downslope, following a trend in soil depth, but the summit A horizon had higher C, N, and organic P concentrations than the backslope, reflecting a higher clay content. Laboratory and field incubations showed that N availability increased downslope, while relative N mineralization (N mineralized: total N) decreased. Organic matter content and mineralization rate were closely coupled to physical properties of the soil, which reflect the geomorphic history of the site.

Landscape and Regional Scale Studies of Nitrogen Gas Fluxes

“…These patterns were driven by the effects of aspect and elevation on soil moisture and the distribution of vegetation. The results are consistent with many other studies that have found strong patterns in N cycling with elevation and aspect (Schimel et al 1985, Burke 1989, Groffman and Tiedje 1989, Bohlen et al 2001). …”

Altitudinal variations in soil physico-chemical properties at cold desert high altitude

“…Hence, increasing trends of SOM content (%) with increasing altitude may be due to the constant carbon inputs and decrease rate of carbon loss at different altitude. Soil texture is another important regulator of soil organic matter decomposition and soil respiration that depends on relative proportion of clay, silt, and sand (Jenny, 1980;Schimel et al, 1985). This hypothesis is also further supported by this study, as in present studied areas comes under sandy loam textural class based on sand and silt fraction of soil.…”

Groundwater recharge in natural dune systems and agricultural ecosystems in the Thar Desert region, Rajasthan, India

“…Soil organic nitrogen (SON) levels should be measured in natural and cultivated regions, and the potential for mineralization and nitrification of soil organic nitrogen should be examined. This source of NO 3 is relied on solely in rain-fed agriculture in some regions of western Canada in the past and also in parts of the USA High Plains (Schimel et al 1985;Tisdale et al 1985). Carbon sequestration in soils through agricultural practices, i.e., minimum or no tillage and management of crop residues, could increase SON levels and may result in increased NO 3 levels in soils.…”