杉木人工林土壤有机碳的垂直分布特征

Vertical distribution of soil organic carbon in Cunninghamia lanceolata plantation

以杉木Cunninghamialanceolata人工林为研究对象,并以不同经营方式的杉木人工林采伐迹地为对照,研究了杉木人工林不同层次土壤中有机碳的垂直分布特征及其与土壤pH值、全氮、C/N比的相关关系。结果表明:杉木人工林土壤有机碳质量分数随着土壤深度的增加而下降,不同层次土壤有机碳质量分数的分异表现为:0～15cm土层(20 6g·kg-1)>15～30cm土层(17 1g·kg-1)>30～45cm土层(12 4g·kg-1)>45～60cm土层(9 8g·kg-1)>60～75cm土层(8 2g·kg-1),3种不同经营方式杉木人工林采伐迹地土壤中平均有机碳质量分数依大小顺序排列为:杉木林地(13 6g·kg-1)>经济林地(12 3g·kg-1)>农用后撂荒地(11 0g·kg-1)。杉木人工林不同层次土壤有机碳质量分数与土壤pH值呈线性正相关,相关系数r≥0 40,与土壤全氮、C/N比呈显著的线性正相关,相关系数分别为r≥0 81和r≥0 87。

Taking Chinese fir plantation as the research objective, vertical distribution of soil organic carbon (SOC) and its relationship with soil pH value, total nitrogen content and soil C/N ratio in Chinese fir plantation were studied. In addition, different land use types of Chinese fir plantation were compared. The results showed that the vertical distribution of SOC in Chinese fir plantation varied with soil depth. The differences of SOC concentration in different layers were as follows: 0-15cm soil layer(20.6 g·kg^(-1))>15-30 cm soil layer(17.1 g·kg^(-1))>30-45 cm soil layer(12.4 g·kg^(-1))> 45-60 cm soil layer(9.8 g·kg^(-1)) > 60-75 cm soil layer(8.2 g·kg^(-1)). Average SOC concentration with three kinds land use types was ranked as follows: the closed Chinese fir forest lands(13.6 g·kg^(-1))>the economic forest lands(12.3 g·kg^(-1))>the fallow lands after farming(11.0 g·kg^(-1)). SOC concentration of different layers in Chinese fir plantation had a positive linear correlation with the soil pH value (r≥0.40), and a significant positive relationship with the contents of total nitrogen (r≥0.81) and C/N ratio(r≥0.87).