氮磷添加对天童常绿阔叶林土壤和细根生态化学计量特征的影响

发布时间：2018-07-07 23:05

本文选题：氮磷交互 + 土壤养分　；参考：《华东师范大学》2017年硕士论文

【摘要】：生态化学计量学是通过元素比例来研究生态过程和生态作用的学科。它为研究土壤-植物相互作用与碳(C)、氮(N)磷(P)循环提供了新的思路。生态化学计量学研究最多的三种元素是C、N和P,其中,N和P是生物生长的限制性养分,C是结构性物质,三者密切相关。大气N沉降不断增加,进而影响生态系统N循环,而对于受P限制的亚热带生态系统而言,P限制可能会更加严重。生态系统C:N:P稳定性对于生态系统物质循环和维系养分平衡具有重要意义。但是,当前缺乏对氮磷因子交互下森林生态系统碳氮磷化学计量关系的生态学解释,因此无法科学预测和准确评估生态系统对复杂气候变化的响应特征。本研究以受P限制的浙江天童亚热带常绿阔叶林木荷(Schima superba)群落为研究对象,进行了氮磷添加实验。实验共设置4种施肥类型:对照(CK:0 kgN/hm2/yr)、氮添加(+N:100kgN/hm2/yr)、磷添加(+P:50kgP/hm2/yr)和氮磷添加(+NP:100kgN/hm2/yr+50kgP/hm2/yr)。通过四个季度的土壤和细根取样以及理化测定,分析了氮磷添加对土壤、细根及细根-土壤系统的C、N、P化学计量特征的影响。主要结果如下:(1)氮磷添加对土壤有机碳和土壤全N均没有显著性影响,+N处理下土壤全P没有显著性改变,+P和+NP处理显著的增加了土壤全P;氮磷添加处理下,土壤C:N和C:P的变化分别与土壤全N和全P显著相关,与土壤有机碳的相关性不明显;土壤N:P的变化与土壤全N和全P都显著相关,但与土壤全P的相关性更强。(2)氮磷添加处理显著增加了土壤细根C含量,但对细根全N没有明显的影响。+N处理对细根全P含量没有显著影响,而+P和+NP处理能够显著增加细根全P含量。氮磷添加处理下,细根C:N的变化主要受细根全N含量的调控,C:P的变化受细根全C和全P共同调控,但与土壤全P的相关性更强,细根N:P的变化受细根N和P的共同调控。(3)氮磷添加处理下,细根全P与土壤全P的变化具有很强的相关性,但细根全C与土壤有机碳、细根全N与土壤全N没有明显的相关性。微生物生物量C、N与土壤有机碳和土壤全N表现出显著性的相关关系,但二者的C:N没有明显的相关性。微生物生物量C与细根全C、微生物生物量N与细根全N以及二者的C:N均无明显的相关性。综上,因研究样地受到P限制,+P处理对土壤和细根的影响比+N处理更明显。氮磷添加处理下,土壤与微生物生物量之间的具有显著的相关性。研究结果可为未来气候变化下陆地生态系统生态化学计量关系的研究提供一定理论依据。
[Abstract]:Eco-chemometrics is a subject that studies ecological processes and ecological effects through the proportion of elements. It provides a new idea for the study of soil-plant interaction with carbon (C), nitrogen (N) and phosphorus (P) cycles. The three elements of ecochemometrics are Con N and P, among which N and P are the limiting nutrients for biological growth and C are structural substances, which are closely related to each other. The atmospheric N deposition is increasing, which will affect the N cycle of the ecosystem, and the P limitation may be more serious for the subtropical ecosystem restricted by P. The stability of ecosystem C: n: P plays an important role in ecosystem material cycle and nutrient balance. However, there is a lack of ecological explanation of carbon, nitrogen and phosphorus stoichiometric relationships in forest ecosystems under the interaction of nitrogen and phosphorus factors, so it is impossible to predict and accurately evaluate the response characteristics of ecosystems to complex climate change. In this study, nitrogen and phosphorus supplementation experiments were carried out on Schima superba community in Zhejiang Tiantong subtropical evergreen broadleaved forest. There were four types of fertilization: CK: 0 kg N / hm 2 / yr, N: 100 kg N / hm 2 / yr, P: 50 kg P / m 2 / yr and N: 100 kg N / hm 2 / yr 50 kg P 路hm 2 / yr = 50 kg / hm ~ (2 / yr), P = 50 kg / hm ~ (2 / yr), respectively. The effects of nitrogen and phosphorus supplementation on the stoichiometric characteristics of soil, fine root and fine root-soil system were analyzed by sampling and physicochemical determination of soil and fine root in four seasons. The main results were as follows: (1) nitrogen and phosphorus supplementation had no significant effect on soil organic carbon and soil total N, but there was no significant change in soil total P under N treatment, P and NP treatments significantly increased soil total P; The changes of soil C: n and C: P were significantly related to soil total N and total P, respectively, but not to soil organic carbon, but soil N to P was significantly correlated with soil total N and total P, respectively. (2) nitrogen and phosphorus addition significantly increased soil fine root C content, but had no significant effect on fine root total N. N treatment had no significant effect on the total P content of fine roots, but P and NP treatments could significantly increase the total P content of fine roots. Under nitrogen and phosphorus addition, the change of C: n in fine root was mainly regulated by the total N content of fine root. The change of C: P in fine root was regulated by total C and total P of fine root, but the correlation with soil total P was stronger. The change of N: P in fine root was regulated by N and P in fine root. (3) the change of total P in fine root was strongly correlated with total P in soil, but there was no significant correlation between total C in fine root and organic carbon in soil, total N in fine root and total N in soil. Microbial biomass C ~ (2 +) was significantly correlated with soil organic carbon and soil total N, but there was no significant correlation between C _ (1) N and C _ (10) N. There was no significant correlation between microbial biomass C and fine root total C, microbial biomass N and fine root total N and their C: n. In conclusion, the effect of P treatment on soil and fine roots was more obvious than that of N treatment because of the P limitation in the study plots. There was a significant correlation between soil and microbial biomass under nitrogen and phosphorus treatment. The results can provide a theoretical basis for the study of ecological stoichiometry of terrestrial ecosystems under climate change in the future.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S718.5

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