长期集约经营对雷竹林土壤碳氮磷库特征的影响

摘要

To study effect of long-term intensive management of Phyllostachys praecox stands on C and nutrients pools in the soil, soil samples were collected from two adjoint Phyllostachys praecox stands that had been subjected to intensive management for 1 and 15 years, separately, in Lin'an County, Zhejiang Province. Different forms of C, N, and P pools were determined and spectral characteristics of soil total organic carbon were analyzed using the nuclear magnetic resonance (NMR) technique. Results show that in comparison to the Phyllostachys praecox stand, 1 year under intensive management, the stand 15 years under intensive management was 248. 5% , 197% , 81. 8% , and 116% higher in soil total organic carbon, water-soluble organic C , hot water-soluble organic C, and readily oxidizable C ( ROC) , respectively, but 17. 6% lower in MBC content. Solid-state NMR spectroscopy of soil samples showed that alkyl C and O-alkyl C dominated soil organic C in Phyllostachys praecox stands. Compared to the Phyllostachys praecox stand 1 year under intensive management, the stand 15 years under intensive management was significantly higher in soil alkyl C content and alkyl C to O-alkyl C ratio (A/O-A) (p <0. 05) , but much lower in aromatic C content and organic matter aromaticity (p <0. 05) , and however remained unchanged in O-alkyl C and carbonyl C. Moreover, in comparison to the Phyllostachys praecox stand 1 year under intensive management, the stand 15 years under intensive management was much higher in soil water-soluble organic N, NH4+-N, NO3--N, available P, and organic P (p <0. 05) , but 36. 5% and 22. 7% lower in microbial biomass N and microbial biomass P, respectively. In conclusion, long-term intensive management helps build up carbon pools and nutrients pools, but significantly affects activity of the soil microbial activity and stability of the organic carbon in the soil.%为了研究长期集约经营对雷竹林土壤碳库与养分库的影响,在浙江省临安市三口镇选择了两块相邻的集约经营雷竹林样地(经营时间分别为1 a和15 a)采样,分析测定了土壤不同形态碳、氮和磷,并利用核磁共振方法分析了土壤总有机碳的波谱特征.结果表明:与集约经营1 a雷竹林相比较,15 a集约经营雷竹林土壤总有机碳、水溶性有机碳、热水溶性有机碳和易氧化碳含量分别增加了249％、197％、81.8％和116％,但微生物生物量碳含量下降了17.6％.土壤有机碳的固态核磁共振结果表明,雷竹林土壤有机碳以烷基碳和烷氧碳为主.与1 a集约经营相比较,15 a集约经营后,土壤烷基碳和烷基碳/烷氧碳比(A/O-A)显著增加(p＜0.05)、芳香碳和芳香度显著下降(p＜0.05),而烷氧碳和羧基碳没有显著变化.与集约经营1 a雷竹林相比较,15a集约经营雷竹林土壤水溶性有机氮、NH4+-N、NO3--N、有效磷和有机磷含量显著增加(p＜0.05),但微生物生物量氮和微生物生物量磷含量分别下降了36.5％和22.7％.综上所述,长期集约经营导致雷竹林土壤碳库和氮磷养分库的贮量显著增加,而土壤微生物活性和土壤有机碳库的稳定性却显著下降.