水保所知识产出(1956---)知识库

Earthworm casts exhibit remarkable fertility and have been widely used as an organic fertilizer. This study
focused on the effects of earthworm cast application on soil aggregates and aggregate-associated carbon in
typical soils from the Loess Plateau (China). Soil column experiments were conducted in the laboratory using
cultivated loessial soil (CS), dark loessial soil (DS), and aeolian soil (AS). Application of earthworm casts
significantly reduced the content of aggregates sized <0.5 mm but increased the content of water-stable ag-
gregates. Compared to without-cast treatment, earthworm cast application increased the organic carbon content
by 13.4–58.3%, 14.4–51.1%, 17.9–45.3%, 16.7–62.4%, 18.4–43.3%, and 19.8–62.9% in soil aggregate fractions
of sizes <0.25, 0.25–0.5, 0.5–1, 1–2, 2–5, and >5 mm, respectively. The application of earthworm casts
significantly increased heavy fraction organic carbon (HFOC), CaCO 3 , and exchangeable Ca contents in soil by
14.5–69.4%, 12.8–51.9%, and 33.3–63.2%, respectively. Compared with macroaggregates, microaggregates had
higher CaCO 3 contents but smaller light-fraction organic carbon (LFOC) to HFOC ratios, indicating that earth-
worm cast application improved the organic carbon stability more in microaggregates than macroaggregates.
Comparison analysis of the three soils showed AS performed better in aggregation and aggregate-associated
carbon stability than CS and DS after applying earthworm casts. The findings improve our understanding of
the effects of earthworm cast application on soil aggregate distribution and aggregate-associated carbon stability,
which will help improve the application efficiency of earthworm casts as an organic fertilizer in the Loess Plateau area.