Abstract:
Objective Sand ridge is the basic geomorphic unit of Gurbantunggut Desert and plays a crucial role in maintaining the stability of the desert ecological environment. Its dynamic changes can significantly affect plant and microbial communities’ distribution and soil nutrient cycling in desert ecosystems.
Method The sand ridges of Gurbantunggut Desert were taken as the research object, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP) and nutrient influencing factors were studied at different depths of sand ridge (0 ~ 2 cm, 2 ~ 30 cm, 30 ~ 60 cm and 60 ~ 100 cm) and different positions (interdune lowland of windward slope, windward slope, ridge top, leeward slope and interdune lowland of leeward slope). The soil nutrient content distribution patterns, ecological stoichiometric characteristics and influencing factors were investigated at different depths and positions of sand ridges.
Results The results showed that: ① With the increase of soil depth, the soil SOC, TN and TP contents showed the phenomenon of surface enrichment, and the contents of SOC and TN in the surface layer were significantly higher than those in other soil layers (
P < 0.05). The nutrient contents of the soil in the sand ridge varied significantly along the vertical spatial gradient. ② Soil SOC, TN and TP contents in 0 ~ 100 cm at different locations showed a general trend of first decreasing and then increasing along the slope direction of the sand ridge, and soil nutrient contents were higher on the leeward slopes and in the lowland between the ridges. ③ The C∶N, C∶P and N∶P of the sandy ridge soils were lower than the average values of the Chinese land and temperate deserts both horizontally and vertically, and the degree of nutrient deficiencies was as follows: C > N > P. ④ The results of redundancy analysis (RDA) showed that the nutrient stoichiometric characteristics of sand ridge soils were mainly influenced by total potassium (TK), ammonium nitrogen (
\rmNH_4^ + -N), microbial carbon (MBC), microbial nitrogen (MBN) and electrical conductivity (EC).
Conclusion Nutrient stoichiometry of sandy ridge soils showed a certain distribution pattern on horizontal and vertical scales, and the influencing factors of nutrient stoichiometry characteristics of different soil profiles were not entirely consistent.