摘要
为比较不同发育阶段杉木人工林土壤团聚体稳定性和有机质变化规律,选取杉木幼龄林、中龄林和成熟林为对象,研究不同发育阶段杉木林土壤总碳、总氮、可溶性有机质、微生物生物量、团聚体分布和稳定性。结果表明：随着林分的发育,表层土壤总氮含量呈增加趋势,总碳先减少后增加,3个发育阶段20~100 cm土层的总碳变化不大。可溶性有机质含量和微生物生物量均随土壤加深而显著下降,0~20 cm土层可溶性有机碳含量随着林龄增加而下降,中龄林微生物生物量碳明显低于幼龄林和成熟林,活性有机质与土壤总碳、总氮、土壤容重、p H值和含水量均存在不同程度相关关系,说明杉木人工林土壤活性有机质含量受多个土壤因素的影响。〉5 mm大团聚体数量和平均重量直径随林分发育呈增加趋势,团聚体破坏率下降。团聚体的稳定性随土层加深而显著下降,中龄林和成熟林深层土壤〉0.25 mm水稳性团聚体比例、平均重量直径、几何重量直径均大于幼龄林,团聚体破坏率低于幼龄林,表明杉木林分的发育有利于底层土壤结构的稳定。土壤团聚体稳定性与土壤粉粒含量、活性有机碳组分、总碳、总氮呈显著正相关。杉木人工林发育到成熟林阶段,土壤碳和氮得到积累,土壤团聚体稳定性显著提高。
In order to compare the change of soil aggregate stability and organic matter in differ- ent development stages of Chinese fir, three stands in young-aged, middle-aged and mature sta- ges were selected to measure soil total carbon, total nitrogen, dissolved organic, matter, microbial biomass, aggregate size distribution and aggregate stability. The results showed that soil carbon content in topsoil decreased first and then increased from middle-aged to mature development stage, and total nitrogen content in topsoil increased with development of Chinese fir plantation, how-ever, total soil carbon content in 20-100 cm soil layer remained unchanged in all three de- velopment stages. Dissolved organic matter and microbial biomass decreased significantly with soil depth. Dissolved organic carbon （DOC） content in 0-20 cm soil layer decreased with the in- creasing stand age. Microbial biomass carbon （MBC） in middle-aged stand in each soil layer was significantly lower than in young-aged and mature stands. There was a significant correlation be- tween active organic matter and total carbon, total nitrogen, bulk density, pH and water content, to some extent, which suggested that soil active organic matter of Chinese fir plantation was af- fected by multiple soil factors. With development of Chinese fir plantation, macro-aggregate of 〉5 mm and mean weight diameter （MWD） in each soil layer increased and aggregate-damaging rate decreased. The stability of aggregates declined with soil depth. The proportion of 〉0.25 mm water-stable aggregate, mean weight diameter and geometry weight diameter of deep soil in middle- aged and mature stands were less than in young-aged stand, which indicated that the development of Chinese fir plantation promoted the stability of soil aggregates in subsoil. A significant positive correlation between soil aggregate stability and silt particle content, active organic carbon frac- tions, total carbon and total nitrogen was found. In conclusion, soil carbon and nitrogen were ac- cumulated and soil structure was improved when Chinese fir plantation develoned to mature stage.
出处
《生态学杂志》
CAS
CSCD
北大核心
2016年第8期2029-2037,共9页
Chinese Journal of Ecology
基金
国家科技支撑计划子课题(2015BAD09B010102)
国家自然科学基金项目(31370531
U1405211)资助
关键词
杉木
发育阶段
有机质特征
水稳性团聚体
活性有机质
Chinese fir
development stage
organic matter characteristics
water-stable aggre-gate
active organic matter.
