Carbon Mineralization Potential in Soils of Different Habitats in the Semiarid Horqin Sandy Land: A Laboratory Experiment

Abstract

Abstract Soil organic carbon mineralization potential in four different sandy habitats (shifting, semi-fixed, fixed sand dune, and interdunal lowland) and the effects of litter addition from shrubs and annual plants on soil microbial respiration were measured using a laboratory soil incubation experiment. Soil samples were collected from beneath and outside the canopies of shrubs in all habitats. Soils were incubated for 33 days with and without litter addition. It was concluded that the differences in C mineralization of soils among habitats correlated with the vegetation cover, litter accumulation, and soil structure, organic C, and N contents. Very poor organic C and N as well as very weak microbial respiration were found in soils of the shifting sand dune, suggesting that sandy desertification strongly depleted both bulk of soil organic C and soil labile C pool. Caragana microphylla litter amended soils and annual plant litter amended soils had the greatest and the lowest microbial respiration, respectively, which might in part be attributed to the N contents and C/N ratios in litters. Shrubs accumulated more organic material and created fertile islands with larger organic C and nutrients and microbial activity under their canopies, and therefore, significantly contributed to C sequestration. Keywords: shrubsannual plantslitterCO2–C releasesandy desertification This study was sponsored by one of the China National Key Projects for Basic Scientific Research: “The bio-process of desertification and the mechanism of recovering and reconstructing of vegetation in desertified Horqin sandy land” (G2000048704). Authors gratefully thank an anonymous reviewer for his valuable comments on this manuscript. Notes Values are means (±standard deviation) of n = 3, *litter mass incorporation into soil (0–5 cm depth). 1Leguminous shrub. 2Mixture of Artemisia scoparia, Salsola collina and Setarria viridis.