School of Agriculture, Ningxia University, Yinchuan, China.
State Key Laboratory Cultivation Base for Northwest Degraded Ecosystem Recovery and Reconstruction, Yinchuan, China.
PeerJ. 2023 Oct 19;11:e16227. doi: 10.7717/peerj.16227. eCollection 2023.
Phosphorus (P) is regarded as one of the major limiting factors in grassland ecosystems. Soil available phosphorus deficiency could affect soil extracellular enzyme activity, which is essential for microbial metabolism. Yet it is still unclear how soil available phosphorus affects soil extracellular enzyme activity and microbial nutrient limitation of desert steppe in the context of climate warming.
This study carried out a short-term open-top chambers (OTCs) experiment in a desert steppe to examine the effects of warming, P addition, and their interaction on soil properties, the activities of soil extracellular enzymes, and stoichiometries.
The findings demonstrated that soil acquisition enzyme stoichiometry of C: N: P was 1.2:1:1.5 in this experiment region, which deviated from the global mean scale (1:1:1). Warming increased soil AN (ammonium nitrogen and nitrate nitrogen) contents and decreased microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN). Phosphorus addition raised soil available phosphorus and microbial biomass phosphorus (MBP) contents. Soil extracellular enzyme activities and stoichiometries in desert steppe are largely impacted by soil AN, MBC: MBP, and MBN: MBP. These results revealed that the changes of soil available nutrients and stoichiometries induced by short-term warming and P addition could influence soil microbial activities and alleviate soil microbial carbon and phosphorus limitation. Our findings highlight that soil available phosphorus played a critical role in regulating soil extracellular enzyme activity and microbial nutrient limitation of desert steppe. Further research on soil microbial communities should explore the microbiological mechanisms underlying these findings.
磷（P）被认为是草原生态系统的主要限制因素之一。土壤有效磷的缺乏会影响微生物代谢所必需的土壤胞外酶活性。然而，在气候变暖的背景下，土壤有效磷如何影响荒漠草原的土壤胞外酶活性和微生物养分限制仍然不清楚。
本研究在荒漠草原进行了短期开顶式气室（OTC）实验，以研究增温和磷添加及其相互作用对土壤性质、土壤胞外酶活性和化学计量的影响。
实验结果表明，试验区土壤获取酶的 C:N:P 化学计量比为 1.2:1:1.5，偏离了全球平均水平（1:1:1）。增温增加了土壤铵态氮（AN）和硝态氮（NO3--N）含量，降低了微生物生物量碳（MBC）和微生物生物量氮（MBN）。磷添加提高了土壤有效磷和微生物生物量磷（MBP）含量。荒漠草原土壤胞外酶活性和化学计量受土壤 AN、MBC:MBP 和 MBN:MBP 的影响较大。这些结果表明，短期增温和磷添加引起的土壤有效养分和化学计量的变化会影响土壤微生物活性，缓解土壤微生物碳和磷的限制。本研究结果表明，土壤有效磷在调节荒漠草原土壤胞外酶活性和微生物养分限制方面起着关键作用。进一步的土壤微生物群落研究应探索这些发现背后的微生物学机制。
