摘要:土壤生态酶化学计量比可用于评估微生物碳（C）、氮（N）和磷（P）养分的需求状况。以往从凋落物输入量变化对生态酶化学计量比的角度来探讨杉木人工林土壤养分状况的研究较少。以亚热带杉木人工林为研究对象，采用随机区组实验设计，对12块杉木人工林样地进行3种凋落物处理（凋落物添加（LA）；凋落物移除（LR）；对照（CK）），通过测定土壤C、N和P水解酶（β-葡糖苷酶（BG）、半纤维素酶（CB）、β-乙酰葡糖胺糖苷酶（NAG）、亮氨酸氨基肽酶（LAP）和酸性磷酸酶（AP））的活性及土壤理化性质，探讨凋落物添加和移除对杉木人工林土壤养分状况的影响。结果表明：LR显著抑制了AP、BG、CB、NAG和LAP活性，同时降低了土壤含水量（SMC）、有机碳（SOC）、总氮（TN）、总磷（TP）和有效氮含量；而LA对以上指标均存在显著的正效应，表明凋落物输入量变化主要是通过改变土壤水分和养分状况来影响水解酶的活性。LR和CK处理下土壤酶活性比ln（BG+CB）：ln（AP）和ln（NAG+LAP）：ln（AP）均低于全球尺度上土壤酶活性比ln（BG+CB）：ln（AP）（0.62）和ln（NAG+LAP）：ln（AP）（0.44），表明亚热带地区杉木人工林土壤微生物生长受磷限制；LA处理的土壤的ln（BG+CB）：ln（AP）和ln（NAG+LAP）：ln（AP）均高于全球尺度，表明LA在一定程度上缓解了土壤磷限制，生态酶化学计量比响应的差异表明磷可能是驱动亚热带杉木人工林土壤生态酶化学计量比内在联系的关键因子。相关分析表明SMC、SOC和有效氮含量与土壤酶活性及其化学计量比呈极显著正相关关系，因此，生态酶化学计量比可作为表征土壤当前养分有效性状况的重要指标，该研究可为亚热带杉木人工林土壤养分管理和可持续性经营提供科学的基础理论。



Abstract:Ecoenzymatic stoichiometry has been widely employed to evaluate the carbon (C), nitrogen (N), and phosphorus (P) requirements of soil microbes. Although the impacts of litter amount alteration on soil nutrient in forest ecosystem have been extensively reported, the elucidation of soil ecoenzymatic stoichiometry related to soil nutrient remains limited. In this study, a field litter manipulation experiment was established in a Chinese fir (Cunninghamia lanceolata) plantation in subtropical China using a randomized block method with three treatments as follows: litter addition (LA), litter removal (LR) and control (CK). The variations in soil hydrolytic enzyme activity (β-glucosidase enzyme (BG), cellulase (CB), β-N-acetylglucosaminidase (NAG), leucine aminopeptidase (LAP), and acid phosphatase (AP)) and soil properties among the three treatments were investigated and the response pattern of soil nutrient to LA and LR treatments was revealed. The results showed that LR reduced all soil enzyme activities in this study, soil moisture content (SMC), soil organic carbon (SOC), total nitrogen (TN), total phosphorous (TP), and mineral nitrogen, while LA had positive effects on the above variables. This result indicated that the variations of the five soil enzymes after litter manipulation were mainly affected by the alteration in soil moisture and nutrient. Moreover, the values of ln(BG+CB):ln(AP) and ln(NAG+LAP):In(AP) of LR and CK were lower than the corresponding values (ln(BG+CB):ln(AP)(0.62) and ln(NAG+LAP):ln(AP)(0.44)) at global scale respectively, which implied that subtropical Chinese fir plantations were limited by phosphorus (P). Additionally, the values of ln(BG+CB):ln(AP) and ln(NAG+LAP):ln(AP) of LA were higher than the corresponding values at global scale, which indicates that P could be the vital factors in driving soil stoichiometric connection with hydrolytic enzyme activities and the limitation of P was alleviated in LA. And the SMC, SOC and mineral nitrogen content were positively correlated with soil enzymatic activity and ecoenzymatic stoichiometry. Our results suggest that the ecoenzymatic stoichiometry can be used as an important indicator to characterize the current soil nutrient availability. This study can provide scientific basis for soil nutrient management and sustainable management of Chinese fir plantations in subtropical China.





PDF全文下载地址:

https://www.ecologica.cn/stxb/article/pdf/stxb201909262020