不同年限红柳恢复川西北高寒沙地对土壤团聚体和有机碳的影响

Effects of Different Age of Alpine Desertification Land Planted Branchy Tamarisk on Soil Aggregates and Organic Carbon in Northwestern Sichuan

利用土壤大团聚体含量(R_(0.25))、平均重量直径(MWD)、几何平均直径(GMD)、团聚体破坏率(PAD)和团聚体对有机碳贡献率(F)指标,研究不同时间尺度红柳恢复川西北高寒沙地对土壤团聚体稳定性和有机碳分布的影响。结果表明:红柳不同恢复年限土壤机械稳定性团聚体和水稳性团聚体都以微团聚体(<0.25mm)组成为主,随着恢复年限增加,表层(0—20cm)>2,0.5~2mm粒级土壤团聚体含量显著增加,表层(0—20cm)土壤团聚体R_(0.25)、MWD和GMD表现为0年<5年<10年<15年,PAD呈现相反的特征;红柳恢复引起表层(0—20cm)土壤有机碳含量显著增加,随着恢复年限增加,>2,0.5~2mm粒级团聚体有机碳含量显著提高,>0.5mm粒级团聚体对土壤有机碳贡献率高达34%~60%;红柳恢复对亚表层(20—40cm)土壤团聚体与有机碳分布特征影响不显著。研究表明土壤团聚体稳定性和有机碳指标可作为川西北高寒沙地土壤生态修复适应性指标,红柳恢复对该区沙化土壤改良具有重要作用。

The macro-aggregates content （R0.25）, mean weight diameter （MWD）, geometric mean diameter （GMD）, the percentage of aggregate destruction （PAD） and contribution rates of aggregates to organic carbon （F）, which were selected to analyze the effects of different age of alpine desertification land planted branchy tamarisk on soil aggregates stability and organic carbon distribution in northwestern Sichuan. The results showed that soil mechanical stability aggregates and water-stable aggregates were mainly composed of micro-aggregates （%0.25 mm） in different restoration years of branchy tamarisk restoration pattern. With the increase of recovery period, soil surface （0-20 cm） 〉2, 0.5~2 mm aggregates increased significantly, and the ranking of R0.25, MWD and GMD from low to high was.0 year %5 years %10 years %15 years, while PAD presented opposite trends. The planting of branchy tamarisk caused a significant increase in soil organic carbon content in the surface layer （0--20 em）. With the increase of recovery period content of 〉2, 0.5~2 mm aggregates increased significantly, and the contribution rates of 〉0.5 , organic carbon mmaggregates to soil organic carbon was 34%-60%. The effect of planting of branchy tamarisk to soil aggregates and organic carbon on sub-surface layer （20-40 cm） was not significant. The results indicated that soil aggregates stability and organic carbon can he used as the adaptable index of soil ecological restoration in northwestern Sichuan, and the planting of branchy tamarisk has an important effect on improvement of desertification soil.