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土壤活性有机质对土壤养分如氮、磷、硫的生物化学循环具有作用,其含量和质量影响土壤的初级生产力。本试验在中国科学院会同森林生态实验站通过对第一代、第二代杉木纯林和地带性阔叶林土壤活性有机质组分的对比研究,发现杉木纯林土壤活性有机质的含量低于地带性阔叶林。第一代杉木纯林易氧化有机碳、微生物生物量碳、水溶性有机碳和水溶性碳水化合物的含量分别比第二代杉木纯林高35.9%、13.7%、87.8%和50.9%,比地带性阔叶林的低15.8%、47.3%、38.1%和30.2%。在调查的三种林地内,土壤微生物生物量碳和水溶性有机碳含量下降幅度较大,其次为水溶性碳水化合物,而易氧化有机碳的变化最小。同时,杉木纯林土壤养分等理化性质也比地带性阔叶林低。这表明在杉木纯林取代地带性阔叶林以及杉木纯林连栽后林地的土壤肥力降低。图3 表2参26。
Soil active organic matter plays a role in the biochemical cycle of soil nutrients such as nitrogen, phosphorus and sulfur, and its content and quality affect the primary productivity of soils. In this experiment, through comparing the active soil organic components in the first generation and the second generation of pure Chinese fir plantations and broadleaved forests, we found that the content of soil active organic matter in pure Chinese fir plantation is lower than that of zonation Broadleaf forest. The contents of DOC, microbial biomass carbon, water-soluble organic carbon and water-soluble carbohydrates in the pure forests of the first generation were respectively 35.9%, 13.7%, 87.8% and 50.9% higher than that of the second-generation Chinese fir plantations, respectively The deciduous forests are 15.8%, 47.3%, 38.1% and 30.2% lower. Soil microbial biomass carbon and water-soluble organic carbon decreased significantly in the three kinds of woodlands surveyed, followed by water-soluble carbohydrates, while changes in readily-oxidizable organic carbon were the least. At the same time, the soil nutrient and other physical and chemical properties of pure Chinese fir plantation are lower than that of the zone broadleaf forest. This indicates that the soil fertility of woodland decreased after the pure Chinese fir was replaced by the broad-leaved forest and the pure Chinese fir plantation. Figure 3 Table 2 Reference 26.