Turnover of intra- and extra-aggregate organic matter at the silt-size scale

摘要: Abstract Temperate silty soils are especially sensitive to organic matter losses associated some agricultural management systems. Long-term preservation of C in these has been demonstrated occur mainly the silt- and clay-size fractions, although our knowledge about mechanisms through which it happens remains unclear. Although such fractions is usually assumed be present form organo–mineral complexes, a large percentage this fraction appears micro-aggregated. In study we hypothesized that slaking-resistant silt-size aggregates should preferential sites long-term soils, by physical entrapment would allow for stabilization interaction with mineral surfaces. To verify this, studied stocks turnover within outside (2–50 μm) after complete dispersion larger (> 50 μm) wheat–maize (C3–C4) chronosequence soil Northern France. Changes natural abundance 13C from C3 C4 plants were used assess time different isolated fractions. Slaking-resistant stored almost half C, both as entrapped light (