有机和常规管理对茶园土壤固碳的影响——以林地为对照

Effects of organic and conventional management on soil carbon sequestration in tea gardens:comparison with forest land

为探究有机和常规管理方式对茶园土壤有机碳的影响,选择云南省普洱市思茅区常规管理茶园、有机管理茶园和附近自然林地3种典型土地利用类型,通过测定0~20 cm和20~40 cm土层的土壤有机碳(SOC)、易氧化有机碳(EOC)、非活性有机碳(NLOC)、颗粒态有机碳(POC)和矿物结合态有机碳(MOC)含量,计算土壤各组分有机碳的分配比例以及土壤碳库管理指数(CPMI),研究3种土地利用方式下土壤有机碳各组分含量和质量的变化特征。结果显示:1)常规管理茶园的SOC含量和储量分别比自然林地低48.67%~51.94%和27.25%~35.71%(P<0.05),而有机管理茶园的SOC含量和储量比常规管理茶园分别高52.09%~62.86%、15.54%~20.26%(P<0.05)。2)常规管理茶园的EOC、NLOC、POC和MOC含量均低于自然林地(P<0.05),而有机管理茶园的EOC、NLOC、POC和MOC含量比常规管理茶园分别高出46.39%~57.89%、54.24%~66.15%、80.87%~121.01%和40.07%~46.28%(P<0.05)。3)与自然林地相比,常规管理茶园的POC/SOC、NLOC/SOC较低,有机管理茶园的POC/SOC、NLOC/SOC则高于常规管理茶园。4)常规管理茶园具有较高的CPAI和较低的CPMI,常规管理茶园的CPMI比自然林地低24.53%~46.12%,有机管理茶园的CPMI比常规管理茶园高67.88%~100.33%,其差异均显著(P<0.05)。以上研究结果表明,与自然林地相比,常规管理的茶园土壤有机碳含量和土壤碳库质量下降,存在一定程度的土地退化,而有机管理是提高茶园土壤碳库质量的有效措施。

To explore the effects of organic and conventional management methods on soil organic carbon in tea gardens,we selected three typical land use types in Simao District,Pu’er City,Yunnan Province to carry out the investigation.The three land use types were a conventionally managed tea garden,an organically managed tea garden,and a nearby natural forest land.Based on the land use types,we measured the contents of soil organic carbon(SOC),easily oxidizable organic carbon(EOC),non-liable organic carbon(NLOC),particulate organic carbon(POC),and mineral-associated organic carbon(MOC)in 0−20 cm and 20−40 cm soil layers in three sample plots.We estimated the distribution ratio of the different types of organic carbon in soil and the soil carbon pool management index(CPMI),and analyzed the changes of the content of SOC component and quality of soil carbon pool from the selected land use types.The results were as follows:1)the content and storage of SOC in the 0–40 cm soil layer of the conventionally managed tea garden were significantly lower than those in the natural forest land by 48.67%−51.94%and 27.25%−35.71%(P<0.05),respectively.The content and storage of SOC in the 0−40 cm soil layer of the organically managed tea garden were respectively 52.09%−62.86%and 15.54%−20.26%higher than those in the conventionally managed tea garden(P<0.05).2)In the 0–20 cm and 20–40 cm soil layers,the contents of EOC,NLOC,POC,and MOC in the soils from the tea garden under conventional management were significantly lower than those from the natural forest land(P<0.05).The contents of EOC,NLOC,POC,and MOC in the soils from the organically managed tea garden were significantly higher than those from the conventionally managed tea garden(P<0.05),which were higher by 46.39%–57.89%,54.24%–66.15%,80.87%–121.01%,and 40.07%–46.28%,respectively.3)The POC/SOC and NLOC/SOC of the tea garden under conventional management were lower than those of natural forest land,while the POC/SOC and NLOC/SOC of organically managed tea garden were higher than those of conventionally managed tea garden.4)Conventionally managed tea gardens had high CPAI and low CPMI.The CPMI of conventionally managed tea garden was 24.53%−46.12%lower than that of the natural forest land(P<0.05),and the CPMI of organically managed tea garden was 67.88%−100.33%higher than that of conventionally managed tea garden(P<0.05).The aforementioned results showed that when compared with natural forest land,the reclamation of tea plantations with conventional management measures can reduce SOC content and soil carbon pool quality,resulting in a certain degree of land degradation.Given the limitations of conventional management,organic management is an effective measure for improving the quality of the soil carbon pool in tea plantations.