Resumen

CELAYA MICHEL, Hernán; GARCIA OLIVA, Felipe; RODRIGUEZ, Julio C.  y  CASTELLANOS VILLEGAS, Alejandro E.. Changes in nitrogen and water storage in the soil of a desert scrub transformed to buffel (Pennisetum ciliare (L.) Link) savanna. Terra Latinoam [online]. 2015, vol.33, n.1, pp.79-93. ISSN 2395-8030.

Land use change is one of the main factors of natural ecosystem degradation, affecting nitrogen and water transfer between patches and reducing their productivity. This paper describes how conversion of desert scrub to savanna in central Sonora (RCS) has affected nitrogen and water pools and availability in the soil. Five sampling patches were chosen for each habitat: under the canopy of Olneya tesota trees (NA) and in the intercanopy bare soil (NI) in the desert scrub. Similarly in the buffel grass savanna under the canopy of the same tree species (SA), in bare soil (SI) and under Buffel grass (SB). We analyzed total and available near-surface soil nitrogen and soil water content at different depths during three years (2010 to 2013). We estimated an annual loss of 12.5 kg N ha-1 due to transformation of the natural scrub ecosystem, where trees and shrubs that serve as fertility islands were dominant, to buffel grass savanna. Soil water content in the topsoil was higher in the bare soil than in other habitats, but habitats with vegetation cover had higher water content than bare soil at 150-200 cm soil depth. Our results suggest that the desert scrub to savanna transformation has led to temporal and spatial decline of soil nitrogen and water. This change has affected the nitrogen and water pools, as well as the soil physical properties, soil fertility and water pools leading to an impact on hydrological budget and function of the transformed ecosystem.

Palabras llave : arid lands; soil water profile; soil nitrogen; desertification; land use change.

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