氮磷添加对杉木林土壤碳氮矿化速率及酶动力学特征的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 氮磷添加对杉木林土壤碳氮矿化速率及酶动力学特征的影响 DOI: 10.5846/stxb201608231718 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41571251，41571130043）；中科院技术创新项目（201604） Effects of nitrogen and phosphorus additions on soil organic carbon and nitrogen mineralization and hydrolase kinetics in Chinese fir plantations Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以江西杉木林红壤为研究对象，开展野外长期氮（N）、磷（P）添加控制试验，设置对照（CK）、N （50kg N hm-2 a-1）、P （50kg P hm-2 a-1）、NP （50kg N hm-2 a-1+50kg P hm-2 a-1）处理，分析N、P添加对土壤碳矿化速率（Cmin）、氮矿化速率（Nmin）和相关的β-1，4-葡萄糖苷酶（βG）和β-1，4-N-乙酰葡糖氨糖苷酶（NAG）动力学参数的影响。结果表明：（1） N添加明显降低了Cmin和Nmin，比CK分别减少了25%和18%；N添加减小了NAG的潜在最大酶活性（Vmax）、半饱和常数（Km）、催化效率（Vmax/Km），但差异不显著（P>0.05）；N添加显著增加了βG的Vmax、Km，但对Vmax/Km有抑制作用。（2） P输入（P、NP）较CK使NAG的Vmax、Km减小26%-60%；NP同时添加明显提高βG和NAG的Vmax/Km（P<0.05），但P输入（P、NP）对Cmin和Nmin影响不显著（P>0.05）。（3）Cmin与土壤溶解性有机碳正相关，Nmin与pH显著正相关，与土壤NH4+-N、NO3--N显著负相关；βG和NAG的Vmax/Km均与NH4+-N、NO3--N负相关（P<0.05），Km均与NH4+-N、NO3--N正相关（P<0.05）。βG的Vmax与NH4+-N、NO3--N正相关（P<0.05），NAG的Vmax与有机碳、全氮、全磷、有效磷负相关（P<0.05）。研究结果表明，在亚热带杉木人工林中，N添加降低土壤pH，增加土壤有效氮含量，抑制βG和NAG的Vmax/Km，对土壤Cmin和Nmin产生抑制作用；而NP添加增加土壤有效磷含量，增加土壤βG和NAG的Vmax/Km。 Abstract:A long-term field experiment of nitrogen (N) and phosphorus (P) additions was established in Chinese fir plantations in subtropical China. Four treatments, i.e. control (CK), N (50kg N hm-2 a-1), P (50kg P hm-2 a-1), and NP (50kg N hm-2 a-1+ 50kg P hm-2 a-1),were selected in this study. We studied the effects of N and P additions on the soil mineralization rate of carbon (Cmin) and nitrogen (Nmin) and the kinetics of β-glucosidase(βG)and N-acetyl-glucosaminidase(NAG). The results showed that (1) N additions had negative effects on Cmin and Nmin, which were lower by 25% and 18%, respectively, compared to CK. (2) P (P, NP) additions decreased the Vmax and Km of NAG by 26%-60% compared to CK, whereas NP combined additions greatly enhanced the catalytic efficiency (Vmax/Km) of βG and NAG (P<0.05). (3) Cmin was positively correlated with dissolved organic carbon (DOC) contents, whereasNmin was positively correlated with pH and negatively correlated with NH4+-N and NO3--N contents. The catalytic efficiencies of βG and NAG were negatively correlated with NH4+-N and NO3--N contents (P<0.05). The Km of βG and NAG was positively correlated with NH4+-N and NO3--N (P<0.05), The Vmax of βG was positively correlated with NH4+-N and NO3--N (P<0.05), and the Vmax of NAG was negatively correlated with soil organic carbon, total nitrogen, total phosphorus, and available contents (P<0.05). Our results suggest that N additions had negative effects on Cmin and Nmin by decreasing soil pH, increasing soil available N contents, and inhibiting the Vmax/Km of βG and NAG, whereas NP additions increased soil available P and the Vmax/Km of βG and NAG in southern subtropical Chinese fir plantations. 参考文献 相似文献 引证文献