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研究土壤团聚体的组成及其有机碳的分布,有助于从微观角度理解土壤结构与功能的相互作用。采用干筛法和湿筛法,研究南方红壤退化地实施人工恢复30年后,马尾松与阔叶复层林(PB)、木荷+马尾松混交林(SP)和阔叶林(BF)3种典型林分在0~60 cm土层的团聚体组成及其有机碳分布特征,分析土壤团聚体有机碳与总有机碳相关关系。结果表明:各恢复林分土壤机械稳定性团聚体质量分数,以>2 mm粒径所占比例最大(均在60%以上),而在水稳性团聚体中,以<0.05 mm粒径占优势。不同林分土壤团聚体结构破坏率顺序依次为BF(53.38%~84.27%)>SP(52.22%~70.86%)>PB(22.70%~47.83%)。机械稳定性和水稳性团聚体有机碳质量分数均以PB最高,随着土层深度的增加,各林分土壤团聚体有机碳质量分数呈下降趋势。水稳性大团聚体(>0.25 mm粒径)有机碳质量分数总体高于相应土层的总有机碳质量分数,而微团聚体的(<0.25 mm粒径)则低于后者,说明有机碳对于大团聚体的形成和水稳性具有积极作用。土壤团聚体有机碳与总有机碳的相关关系分析表明,土壤团聚体有机碳的增加,对总有机碳的积累具有正面影响。保留密度大、灌木(草)层盖度高的马尾松与阔叶复层林土壤团聚体的数量和质量更高;因此,在红壤侵蚀退化地森林恢复初期,可通过适当密植、增加林下灌草覆盖等措施,增加有机碳的输入,促进团聚体的形成和稳定,从而加速了退化土地的土壤结构改善和功能恢复。该研究可为南方严重红壤退化地生态恢复中的林分类型选择和优化配置提供科学依据。
Studying the composition of soil aggregates and their distribution of organic carbon is helpful to understand the interaction between soil structure and function from the microscopic point of view. Using dry sieving method and wet sieving method, we studied the effects of Pinus massoniana and Broadleaved mixed forest (PB), Schima superba + Masson pine mixed forest (SP) and broadleaf forest (BF) 3 The composition of aggregates and their distribution of organic carbon in typical stands in 0 ~ 60 cm soil layer were analyzed. The correlations between organic carbon and total organic carbon in soil aggregates were analyzed. The results showed that the mass fractions of soil mechanical stability aggregates in each restoration stand were the largest (> 60%) in the proportion of> 2 mm, while in the water stable aggregates, Advantage. The destructive rates of soil aggregates in different stands were BF (53.38% ~ 84.27%)> SP (52.22% ~ 70.86%)> PB (22.70% ~ 47.83%). The mechanical properties and water stable aggregates of organic carbon were the highest in PB, with the soil depth increasing, the organic carbon content of soil aggregates showed a downward trend. The mass fraction of organic carbon in the water-stable macroaggregates (> 0.25 mm particle size) is generally higher than the total organic carbon mass fraction in the corresponding soil layers, whereas the microaggregates (<0.25 mm particle size) are lower than the latter Carbon has a positive effect on the formation and stability of large aggregates. Correlation analysis between soil organic carbon and total organic carbon showed that the increase of organic carbon in soil aggregates had a positive effect on the accumulation of total organic carbon. The mass and mass of soil aggregates in the masson pine and broad-leaved mixed forest with high reserve density and shrub (grass) coverage were higher. Therefore, in the early stage of forest restoration after degraded red soil erosion, Grass cover and other measures to increase the input of organic carbon to promote the formation and stability of aggregates, thus accelerating the improvement of soil structure and function recovery of degraded land. This study can provide a scientific basis for the selection of types of forest and the optimal allocation of ecological restoration of degraded red soils in southern China.