Wang Chao, Yang Qiannan, Zhang Chi, Zhang Xiaolong, Chen Jing, Liu Kexue
School of Resources and Planning, Guangzhou Xinhua University, Guangzhou, China.
Ecological Restoration Research Center, China Institute of south China Urban-Rural Economic and Social Development, Guangzhou, China.
Front Plant Sci. 2023 Feb 28;14:1116179. doi: 10.3389/fpls.2023.1116179. eCollection 2023.
The microbial requirement for nutrient resources can be estimated by soil extracellular enzyme stoichiometry (EES) and their stoichiometries. Implementing the Grain for Green Program has significantly impacted land use and soil nutrient management in the China Danxia. However, drivers of soil microbial nutrient limitation changes in abandoned cropland (AC) remained unclear after vegetation restoration. Here, according to vector analysis, we evaluated microbial nutrient limitation by studying soil EES across vegetation restoration types (naturally restored secondary forests (NF) and artificially planted forests (AF)) with AC as a control. Results showed both NF and AF soils averaged higher C- and P- acquiring enzyme, indicating rapid C and P turnover rates after vegetation restoration. However, vegetation restoration resulted in higher C requirement for microorganisms with higher enzyme C:N and vector length. In addition, microorganisms shifted from N- (< 45°) to P-limited (> 45°) conditions with enzyme N:P less than 1 after vegetation restoration, and NF exacerbated microbial P limitation compared to AF. Decreased N limitation following vegetation restoration could be contributed to improving soil ecosystem multifunctionality. The greater variation of EES was explained by the interaction of pH, soil nutrient, and microbial biomass than by any one of these factors alone, suggesting that both abiotic and biotic factors regulate microbial nutrient limitation and microbial process. Overall, our results revealed vegetation restoration could alleviate N limitation in the China Danxia, and thus enhance soil ecosystem by regulating lower microbial N limitation, which provide insight into nutrient management strategies under ecological restoration of degraded areas.
微生物对养分资源的需求可通过土壤胞外酶化学计量学（EES）及其化学计量来估算。实施退耕还林工程对中国丹霞地区的土地利用和土壤养分管理产生了重大影响。然而，植被恢复后，弃耕地（AC）土壤微生物养分限制变化的驱动因素仍不明确。在此，根据向量分析，我们以AC为对照，通过研究不同植被恢复类型（天然恢复次生林（NF）和人工造林（AF））的土壤EES来评估微生物养分限制。结果表明，NF和AF土壤中获取碳和磷的酶平均含量较高，表明植被恢复后碳和磷的周转率较快。然而，植被恢复导致微生物对碳的需求增加，酶的碳氮比和向量长度更高。此外，植被恢复后，微生物从氮限制（<45°）转变为磷限制（>45°），酶的氮磷比小于1，与AF相比，NF加剧了微生物的磷限制。植被恢复后氮限制的降低可能有助于改善土壤生态系统多功能性。EES的较大变化是由pH值、土壤养分和微生物生物量的相互作用解释的，而不是由这些因素中的任何一个单独解释的，这表明非生物和生物因素都调节微生物养分限制和微生物过程。总体而言，我们的结果表明植被恢复可以缓解中国丹霞地区的氮限制，从而通过调节较低的微生物氮限制来增强土壤生态系统，这为退化地区生态恢复下的养分管理策略提供了见解。
