土壤活性有机碳(SLOC)在土壤许多物理、化学和生物特性中发挥着重要作用。连续3年(2016—2018年)系统地研究和比较了不同园林植物(夹竹桃Apocynaceae、石楠Photinia serrulata、广玉兰Magnolia grandiflora、大叶女贞Ligustrun lucidum)土壤活性有机碳组分和有机碳储量特征。结果 表明:(1)在垂直方向,不同年份园林植物土壤有机碳含量均随着土层深度的增加而逐渐降低,表现出明显的“表聚性”,其中表层随着年份的增加其增加趋势较为明显,深层有机碳含量随年份的变化不明显。此外,不同年份不同土层深度不同园林植物土壤有机碳含量均表现为夹竹桃和石楠显著高于广玉兰和大叶女贞。(2)土壤有机碳储量与土壤有机碳呈一致的变化规律,均随着土层深度的增加而逐渐降低。(3)不同园林植物土壤易氧化有机碳(EOC)、颗粒有机碳(POC)、轻组有机碳(LFOC)和水溶性有机碳(WSOC)均随着土层深度的增加而逐渐降低,表层最大,表现出明显的“表聚性”,其中表层随着年份的增加其增加趋势较为明显,深层有机碳储量随年份的变化不明显。相同土层夹竹桃和石楠土壤易氧化有机碳(EOC)、颗粒有机碳(POC)、轻组有机碳(LFOC)和水溶性有机碳(WSOC)均高于广玉兰和大叶女贞。(4)土壤活性有机碳与土壤总有机碳均呈显著的线性关系,说明土壤活性有机碳依赖于土壤总有机碳含量。(5)交互分析表明:土层深度和林型对土壤有机碳和活性有机碳具有显著的影响(p<0.05),年份对土壤有机碳和活性有机碳没有显著影响(p>0.05),其中林型×土层深度对土壤有机碳和活性有机碳具有显著的影响(p<0.05)。
As an important index of soil quality, soil active organic carbon(SLOC)plays an important role in many physical, chemical and biological properties of soil. From August 2016 to August 2018, through sampling and analysis of soil samples under different garden plants for three consecutive years, the characteristics of active organic carbon components and organic carbon reserves in soils under different garden plants were systematically studied and compared. The results showed that:(1)in the vertical direction, the organic carbon contents in the soils of garden plants in different years gradually decreased with the increase of soil depth, showing an obvious surface aggregation, among which the surface layer increased with the increase of years, while the organic carbon content in deep layer did not change significantly with the increase of years; in addition, the soil organic carbon contents under garden plants in different years and at different soil depths were significantly higher under oleander and heather than those under magnolia and privet;(2)the storage of soil organic carbon was consistent with the change rule of soil organic carbon content; the storages of soil organic carbon under garden plants in different years gradually decreased with the increase of soil depth, among which the increase trend of surface layer was more obvious with the increase of year, while the change of deep layer organic carbon content was not obvious with the increase of year;(3)soil easy oxidation organic carbon(EOC), particulate organic carbon(POC), light organic carbon(LFOC)and water soluble organic carbon(WSOC)under landscape plants of different particulate decreased with the increase of soil depth, the contents of these organic carbon fractions in surface layer were the largest, indicating the apparent agglomeration of soil organic carbon fractions in the topsoil, the increases of soil organic carbon in the surface layers were significant with the increase of the years, the changes in organic carbon reserves in deep layers were not significant over the years; in the same soil layer, EOC, POC, LFOC and WSOC under Apocynaceae and Photinia serrulatawere higher than those under Magnolia grandiflora and Ligustrun lucidum;(4)there were a significant linear relationship between soil active organic carbon and soil total organic carbon, which indicated that soil active organic carbon was dependent on soil total organic carbon content and characterized the carbon content of the more active part of soil from different perspectives;(5)interactive analysis showed that soil depth and plant types had significant effects on soil organic carbon and active organic carbon (p<0.05), while years had no significant effects on soil organic carbon and active organic carbon (p>0.05); the interaction of plant types and soil depths had significant effects on soil organic carbon and active organic carbon (p<0.05), however, the interactions of plant type and year and the interaction of soil depth and year had no significant effect on soil organic carbon and active organic carbon (p>0.05).
