生草栽培对果园土壤团聚体及其有机碳分布的影响

以福建尤溪玉池生草果园定位观测点为平台,研究了生草栽培对果园土壤团聚体有机碳分布的影响。结果表明,生草栽培处理后,0~20 cm土壤团聚体中>0.25 mm水稳性团聚体的比例(R0.25)、平均重量直径(MWD)和几何平均直径(GWD)分别比顺坡清耕和梯台清耕处理的高3.78%~5.90%、16.82%~20.94%、5.86%~50.31%和3.81%~13.82%、13.33%~19.95%、7.50%~60.63%,分形维数比顺坡清耕和梯台清耕处理的低1.54%~2.35%和1.09%~9.64%。同时,生草栽培可提高>2 mm土壤团聚体内有机碳贮量和大团聚体有机碳贮量占总有机碳的比例,但其影响主要集中于0~20 cm土层。这说明生草栽培处理更有利于提高土壤团聚体稳定性,增强土壤有机碳的保护和碳汇作用。

Effects of Sod Cultivation in Orchard on Distributions of Soil Aggregates and Soil Organic Carbon of Aggregates

The effects of sod cultivation in orchard on distribution of organic carbon in soil aggregates were investigated, which located in Yuchi Village, Youxi Xian, Fujian Province. The results showed that compared with downslope and landings clean tillage orchards, the proportion of >0.25 mm water-stable aggregate (R_0.25), mean weight diameter (MWD), and geometric mean diameter (GWD) of soil aggregate at 0-20 cm soil layer in sod cultivation orchard increased by 3.78%-5.90%, 16.82%-20.94%, 5.86%-50.31% and 3.81%-13.82%, 13.33%- 19.95%, 7.50%-60.63%, and the fractal dimension decreased by 1.54%-2.35% and 1.09%-9.64%, respectively. The sod cultivation could improve proportion of organic carbon storage in large aggregates (>2 mm) to total organic carbon at 0-20 cm soil layer. Therefore, the sod cultivation was beneficial to improve stability of soil aggregate, and could enhance the protection of organic carbon and carbon sink in soil.