Abstract: Elucidating the soil quality of different types of shrubland in the Hobq Desert and identifying the nutrient limitation status of shrub growth are of great significance for shrubland management and conservation. We collected soil samples from 0-10, 10-30, and 30-50 cm layers in shrub communities of Ceratoides latens, Tetraena mongolica, and Sarcozygium xanthoxylon, and analyzed soil organic matter (OM), total nitrogen (TN), total phosphorus (TP), and total potassium (TK) contents as well as their stoichiometric ratios. We further explored the correlations among the indicators and nutrition limitation factors for plant growth. The results showed that there were significant differences (P<0.05) in the contents of OM, TN, TP, and TK in the 0-50 cm soil layers among the three shrublands. Specifically, the contents of OM, TN, TP, and TK in the soil of the C. latens community showed a decreasing trend with increasing soil depth. However, the variations in total soil nutrient contents in the S. xanthoxylon and T. mongolica communities with increasing soil layers were inconsistent. There was a significant positive correlation among OM, TN, TP, N∶P, N∶K, and P∶K in the soil of the C. latens community (P<0.05), while TK was significantly negatively correlated with OM, TN, TP, N∶P, N∶K, and P∶K (P<0.05). Those results indicated that soil of shrubland reflects to some extent the inherent coupling and balance mechanism among various nutrient elements. There was a significant positive correlation between TN, TK, and N∶K in the soil of the S. xanthoxylon community (P<0.05), and a significant negative correlation between TP and TK and N∶P and N∶K (P<0.05). There were significant positive correlations between OM and TN, TK, N∶P, and N∶K (P<0.05), but negative correlation between TP and P∶K in the soil of the T. mongolica community (P<0.001). The growth of three shrubs was limited by N and K. Our results provide a theoretical basis for the management and maintenance of shrublands in the Hobq Desert.

Key words: Hobq Desert, nutrient content, stoichiometric ratio, shrub, soil depth