Plant species effect on the spatial patterns of soil properties in the Mu-us desert ecosystem, Inner Mongolia, China

Although Artemisia ordosica Krasch. and Sabina vulgaris Ant. are the domina nt shrub species in the Mu-us desert ecosystem, they differ in their botani cal traits. We investigated the spatial patterns of soil properties using g eostatistical analysis to examine the effect of plant species on these spat ial patterns. Comparison among three microsite types (under A. ordosica, un der S. vulgaris, and the opening between vegetation) showed that A. ordosic a generally had less effect than S. vulgaris on local soil properties. The long life-span, prostrate life-form, and evergreen leaf-habit of S. vulgari s may lead to a higher accumulation of organic and fine materials under S. vulgaris. The range of spatial autocorrelation found in the mass of organic matter on the soil surface was smaller than that of the coverage of S. vul garis (11.5 m) which corresponded to the canopy patch size of this species, and was longer than the canopy patch size of A. ordosica. The ranges of to tal C and N, and pH (11.7-15.6 m) were similar to that of S. vulgaris. The range of available P (106.3 m) was comparable to that of the coverage of A. ordosica (86.2 m) considered to be the scale of the distribution of this s pecies. The ranges of silt+clay and exchangeable K, Ca, and Mg (31.0-46.7 m ) were not related to plant presence, and were similar to that of topograph y (43.1 m).