豫东南沙地4种人工林土壤团聚体稳定性及有机碳分布研究

Soil Aggregates Stability and Organic Carbon Distribution of Four Plantations in Sandy Land of Henan Southeastern Area

为探究林分类型对土壤团聚体稳定性及有机碳分布特性的影响,以豫东南沙地4种典型人工林(桂花、合欢、栾树和女贞)为研究对象,通过野外调查、取土壤样品和室内试验对土壤团聚体和有机碳进行测定、分析。结果表明,①4种林分类型下土壤大团聚体(>0.25mm)含量最高,占林地土壤总团聚体的69.63%%~97.30%,粒径0.25~0.15mm团聚体含量最低,且不同林分类型下各层土壤团聚体的质量分数呈现不同的差异。②表层(0~10cm)土壤团聚体平均质量直径(MWD)、几何平均直径(GMD)均表现为栾树>合欢>桂花>女贞,分形维数(D)排序则与之相反,变化范围为2.515~1.653,栾树的土壤结构稳定性最强。③随土壤团聚体粒径的减小,4种林分土壤有机碳含量总体上呈现先升后降趋势,土壤剖面上也表现出随土层加深而下降。不同林分类型下,土壤有机碳含量差异性表现为合欢最高,栾树最低,变化范围分别为45.76~7.65和17.78~3.49g/kg。④回归分析表明,女贞林分下土壤大团聚体与有机碳含量相关性最强,土壤有机碳可解释17.5%土壤大团聚体含量的变化。研究得出该地区栾树林下土壤团聚体稳定性较强,合欢林下土壤有机碳含量最高。

The effects of forest types on soil aggregates stability and organic carbon distribution were studied by field survey,sample collection and lab analysis in Osmanthus fragrans,Albizia julibrissin,Koelreuteria paniculata,Ligustrum lucidum forest of sandy land in Henan southeastern area.The results showed as follows:① The content of soil macro-aggregates(>0.25 mm)was the highest in the four forest types,accounting for 69%~97% of the total soil aggregates,and the content of soil macro-aggregates with a diameter of 0.25~0.15 mm was the lowest in the four forest types,and the content of soil aggregates was different among different forest types.②The MWD and GMD of soil aggregates in the surface layer (0~10 cm) were Koelreuteria paniculata > Albizia julibrissin >Osmanthus fragrans>Ligustrum lucidum.The variation of fractal dimension(D) ranged from 2.515 to 1.653,and the structural stability of Koelreuteria paniculata was the strongest.③With the decrease of soil aggregate size,the content of soil organic carbon in the four stands increased first and then decreased.The content of organic carbon in soil profile decreased with the deepening of soil layer.Under different forest types,the soil organic carbon content of Albizia julibrissin Durazz was the highest and Koelreuteria paniculata was the lowest with the variation range of 22.35~8.50 and 13.72~3.09 g/kg,respectively.④ The regression analysis showed that there was the strongest correlation between soil macro-aggregates and organic content in the Ligustrum lucidum forest,and soil organic carbon could explain the changes of 17.5% soil macro-aggregates content.It was concluded that the soil aggregates of Koelreuteria paniculata was more stable,and the soil organic carbon content of Albizia julibrissin was the highest.