Yang Yaru, Liu Weiguo, Adams Jonathan M, Song Bin
College of Ecology and Environment, Xinjiang University, Urumqi, China.
Key Laboratory of Oasis Ecology of Education Ministry, Xinjiang University, Urumqi, China.
Front Plant Sci. 2023 Jul 20;14:1166897. doi: 10.3389/fpls.2023.1166897. eCollection 2023.
Desert ecosystems are sensitive to nitrogen (N) deposition. Considering snow is an important source of soil water, which is vital for plant growth and the biogeochemical cycle in desert areas. The effects of N deposition on biological soil crusts (BSCs) could be impacted by the removal of snow-cover. Here, we established a split-plot experiment in the Gurbantunggut Desert to examine the effects of snow-cover treatments on soil nutrients, enzyme activities, and the bacterial community under various N addition. The removal of snow-cover reduced the soil nutrients with light and moderate N addition, it also reduced the activities of urease (URE) and alkaline phosphatase (PHOS). The structural equation model (SEM) result indicated that low soil moisture (SMO) under snow-uncover inhibited the bacterial community, particularly suppressed bacterial diversity. Additionally, N addition indirectly affected the bacterial community modifications to soil nutrients, and soil organic matter (SOM) ( < 0.001) was the crucial factor. Snow-uncover weakened soil nutrient and enzyme responses to N addition, indicating that snow-cover removal reduced the sensitivity of the desert ecosystem to N deposition. The study highlights the critical role of snow-cover in the desert ecosystem, raising our awareness of the ecological risks of BSCs in future global change.
沙漠生态系统对氮（N）沉降敏感。鉴于雪是土壤水分的重要来源，而土壤水分对沙漠地区的植物生长和生物地球化学循环至关重要。去除积雪可能会影响氮沉降对生物土壤结皮（BSCs）的影响。在此，我们在古尔班通古特沙漠开展了一项裂区试验，以研究在不同氮添加水平下，积雪处理对土壤养分、酶活性和细菌群落的影响。去除积雪在轻度和中度氮添加情况下降低了土壤养分，还降低了脲酶（URE）和碱性磷酸酶（PHOS）的活性。结构方程模型（SEM）结果表明，无雪覆盖下较低的土壤湿度（SMO）抑制了细菌群落，特别是抑制了细菌多样性。此外，添加氮间接影响细菌群落对土壤养分的改变，且土壤有机质（SOM）（<0.001）是关键因素。无雪覆盖削弱了土壤养分和酶对氮添加的响应，表明去除积雪降低了沙漠生态系统对氮沉降的敏感性。该研究突出了积雪在沙漠生态系统中的关键作用，提高了我们对未来全球变化中生物土壤结皮生态风险的认识。
