外源新碳在不同类型土壤团聚体中的分配规律

DISTRIBUTION OF FRESH CARBON IN AGGREGATE FRACTIONS OF DIFFERENT SOIL TYPES

通过室内模拟实验,利用δ13C方法研究外源新碳(13C标记的水稻秸秆)在不同类型土壤(红壤、黄红壤和草甸土)团聚体中的分配规律。培养温度为25°C,培养时间为360 d。结果表明:在三种类型土壤中,外源新碳进入到土壤团聚体中的数量由大到小顺序依次为250～2 000μm、50～250μm和<50μm。而进入到土壤中的外源新碳,56.8%～59.6%残留在250～2 000μm团聚体中,25.9%～28.7%残留在50～250μm团聚体中,11.7%～17.3%残留在<50μm团聚体中,表明新进入的外源碳主要分配在大团聚体中。

Using the stable carbon isotope （δ^13C） technique, an indoor incubation experiment was carried out to study distribution of fresh carbon in soil aggregate fractions of red soil （Ferrisols） , yellowish red soil （Luvisol） and mountain meadow soil （Cambisols）. To trace dynamics of fresh carbon in soil aggregates δ^13C-labelled rice straw was applied to the soils, which were then put under incubation at 25℃ for 360 days. Results show that the quantity of the fresh carbon found in soil aggregates followed a decreasing order of 250 - 2 000 μm 〉 50 - 250 μm 〉 〈 50 μm in all these soils, accounting for 56.8% - 59.6% , 25.9% - 28.7% and 11.7% - 17.3% , respectively, of the total applied into the soil, which further indicates that the added fresh carbon was mainly accumulated in large-sized soil aggregates.