湘中紫色丘陵区不同植被类型根际与非根际土壤理化特征

目的]探索湘中紫色丘陵区不同植被类型根际与非根际土壤的理化特征,为湘中地区生态修复提供理论依据。方法]以典型抽样方法调查湘中丘陵区草丛(G)、草灌(GS)、灌木(S)和乔灌(AS)4种典型植被,研究其根际与非根际土壤理化性质的差异,通过典型相关分析揭示根际与非根际土壤理化指标间的耦合关系。结果]研究区草丛和灌木根际土壤中细砂粒(0.25~0.05mm)含量分别显著(p0.05)低于乔灌63.84%和76.97%;粉粒(0.02~0.002mm)含量表现为草和灌木分别显著高于乔灌的38.48%和37.66%。根际土壤0.25~0.05mm微团聚体含量均表现为乔灌高于其他植被,0.02~0.002mm微团聚体含量均表现为灌木高于其他植被。草灌与灌木非根际土壤有机质含量显著(p0.05)低于根际土壤148.05%和121.92%,灌木和草灌根际土壤有机质含量显著(p0.05)高于乔灌土壤84.28%和92.08%;草灌根际土壤全氮含量显著(p0.05)高于非根际土壤83.33%,草灌根际土壤碱解氮含量显著(p0.05)高于乔灌土壤200.83%;不同植被类型根际/非根际土壤磷含量差异不明显,总体来看,同一植被根际土壤全磷含量低于非根际土壤,而有效磷表现为乔灌最低;乔灌根际土壤速效钾含量分别显著(p0.05)低于草丛和草灌土壤125.15%和137.71%,除草灌外,其余植被类型根际土壤全钾含量均低于非根际土壤。典范相关分析表明土壤有机质和全量养分含量,2~1,1~0.5,0.25~0.05mm土粒含量,2~1,1~0.5mm团聚体3组理化性状间相互关系密切。结论]改善土壤理化性质,促进湘中丘陵地区生态恢复,应注重协调土壤养分、颗粒组成及团聚体之间的耦合关系。

Physicochemical Characteristics of Rhizosphere and Non-rhizosphere Soils Under Different Vegetation Types in Purple Soil Hilly Region of Central Hu'nan Province

Objective] To explore the physicochemical characteristics of rhizosphere and non-rhizosphere soils under different typical types of vegetation in purple soil hilly region of central Hunan Province, and to provide theoretical basis for ecological restoration.Methods] The physical and chemical properties of rhizosphere and non-rhizosphere soils from grass(G), grass-shrub(GS), shrub(S) and arbor-shrub(AS) were obtained by sampling and experimental analysis to reveal the coupling relationships with regard to the indexes of physical and chemical properties of between rhizosphere and non-rhizosphere soils.Results] The contents of fine sand(0.25~0.05 mm) in G and S rhizosphere soils were 76.97% and 63.84% lower that of AS (p<0.05). Whereas, the silt contents were 38.48% and 37.66% higher. The content of 0.25~0.05 mm microaggregate in the AS rhizosphere soil was higher than those of others and the 0.02~0.002 mm microaggregate content of S rhizosphere soil was the highest. The organic matter contents of GS and S in non-rhizosphere soil, were 148.05% and 121.92% (p<0.05) lower than the corresponding ones in rhizosphere soil. Organic matter contents in S and GS rhizosphere soils were 84.28% and 92.08% (p<0.05) higher that of AS. The total nitrogen content in GS rhizosphere soil was 83.33% higher than that in non-rhizosphere soil. The available nitrogen in GS rhizosphere soil was 200.83% higher (p<0.05) than that of AS. Either in rhizosphere soil or in non-rhizosphere soil, phosphorous contents had no significant differences among all types of vegetation. For the same type of vegetation, soil total phosphorous content in rhizosphere soil was lower than that in non-rhizosphere. Soil available phosphorous content in AS was the lowest. In comparison with the ones of G and GS, the available potassium content in AS rhizosphere soil was 125.15% and 137.71% lower(p<0.05). There were closed relationships among the three groups of soil physicochemical indices, referring to the group of soil organic matter and total nutrient content, the group of 2~1 mm, 1~0.5 mm, 0.25~0.05 mm particles and the group of 2~1 mm,1~0.5 mm aggregates.Conclusion] The coupled relations among soil nutrient, soil particle and soil aggregates should be applied to improve soil physicochemical properties and accelerate the ecosystem restoration in hilly region of central Hunan Province.