名山河流域不同类型土壤腐殖质的组成特征

以名山河流域不同类型土壤为研究对象,研究了3种土壤类型(黄壤、紫色土、水稻土)和4种土地利用方式(水田、旱地、果园、茶园)下腐殖质的组成特征。结果表明:名山河流域3种类型土壤腐殖质含碳量为9.74~21.66g/kg,表层土壤(0—20cm)大于下层土壤(20—40cm),含量由高到低依次为水稻土紫色土黄壤,水稻土与紫色土、黄壤腐殖质碳含量差异显著,腐殖质各组分碳含量间呈极显著正相关(P0.01);从土地利用方式看,水田腐殖质含碳量显著高于果园、茶园和旱地,且腐殖质碳含量与HA含量呈极显著正相关(P0.01);土壤的腐殖化程度表现为黄壤紫色土水稻土。不同利用方式下重组碳含量表现为水田果园茶园旱地,茶园表层土壤腐殖质松紧比最大(1.37),为水田下层土壤的2.14倍;3种类型土壤团聚体中HA含量为0.02~4.57g/kg,且随着粒径的减小呈现先降低后增加的趋势,除2~5,0.25mm粒径团聚体外,5,1~2,0.5~1,0.25~0.5mm粒径团聚体均与其HA含量呈正相关(P0.05)。土壤腐殖质组成受土壤类型及人为耕作管理活动的影响,4种土地利用方式下水田土壤肥力最高,HA含量受5mm粒径团聚体影响最大。

Composition Characteristics of Humus in Different Types of Soil in the Mingshan River Watershed

The distribution of soil humus was studied under three soil types (yellow soil, purple soil and paddy soil) and four patterns of land use (paddy fields, dryland, orchard and tea garden), samples were collected in Mingshan River watershed. The results showed that the carbon content of three types of soil humus was between 9.74 and 21.66 g/kg, and the content of the surface soil (0-20 cm) was greater than that of the lower soil (20-40 cm), and the content followed the order of paddy soil>purple soil>yellow soil. The carbon content of paddy soil was significantly greater than those of purple soil and yellow soil. The carbon content of each humus component was significantly positively correlated (P<0.01). From the way of land use, the carbon content of paddy humus was significantly larger than that of orchard, tea garden and dry land, and it was significantly correlated with HA (P<0.01), and the degree of humification of soil was yellow soil>purple soil>paddy soil. The content of the recombinant carbon in different utilization modes was paddy field>orchard>tea garden>dry land. The ratio of the loose humus to the tight humus in the tea garden was the maximum (1.37), which was 2.14 times as high as that of the lower soil of the paddy field. The content of HA in the three types of soil aggregates was between 0.02 and 4.57 g/kg, and the content of the humic acid content decreased first and then increased with the decreasing of the particle size. Except for 2~5 and <0.25 mm aggregates, the aggregates with the sizes of >5, 1~2, 0.5~1 and 0.25~0.5 mm were positively correlated with HA content (P<0.05). In conclusion, soil humus composition was affected by soil types and artificial cultivation management activities. Paddy field soil fertility was the highest, and the content of HA was most affected by aggregates larger than 5 mm.