长期有机肥施用、秸秆还田对塿土团聚体及其有机碳含量的影响

Effects of Long-term Organic Inputs on Distribution of Aggregate Size and its Organic Carbon Content on Lou Soil

借助于18年冬小麦-夏玉米长期定位试验,探讨了施肥对塿土干筛团聚体组成及有机碳含量的影响。试验涉及4个处理：不施肥（CK）;单施化肥（NPK）;有机肥＋化肥配合施用（MNPK）;秸秆还田＋化肥配合施用（SNPK）。结果表明,长期施用NPK或MNPK或SNPK对土壤干筛团聚体大小的分布没有显著影响,但有增加〉2 mm团聚体含量的趋势。长期施肥能显著提高土壤有机碳含量以及各大小团聚体有机碳的含量。在0~10 cm土层中,不同干筛团聚体中有机碳含量均随着干筛团聚体变小而增大,〈0.25 mm干筛团聚体有机碳含量最高。长期施用有机肥,秸秆还田能显著增加0~10 cm土层全碳在〉7 mm和1~3 mm团聚体中的分配比例。尽管施肥对干筛团聚体分布没有显著影响,但有机物与NPK配施能显著提高小团聚体有机碳含量,这可能对土壤有机碳起到保护作用。

This study investigated the effects of 18-year organic inputs on dry-sieve aggregate size distribution and its organic carbon content on Lou soil.The experiment included four treatments： nil fertilizer（control,CK）,combination of chemical fertilizers of nitrogen,phosphorus and potassium（NPK）,NPK plus dairy manure（MNPK）,and NPK with straw incorporated（SNPK）.Soil samples were separated into nine aggregate-size classes（10 mm,10-7 mm,7-5 mm,5-3 mm,3-2 mm,2-1 mm,1-0.5 mm,0.5-0.25 mm and 0.25 mm）.No significant difference was observed for the distribution of dry aggregates by fertilization compared with the control.However,fertilization tended to increase the proportion of aggregates over 2 mm.The soil organic carbon（SOC） content and the SOC in aggregates were significantly higher in the fertilized treatments than the control.The SOC increased as the size of dry aggregates decreased in all treatments in 0-10 cm soil depth.The SOC concentration was highest in aggregates 0.25 mm.Long-term organic inputs（MNPK and SNPK） significantly increased SOC of aggregates over 7 mm and 1-3 mm in contrast to the control in the 0-10 cm soil depth.Although fertilization didn＇t affect the distribution of dry aggregates,organic inputs increased SOC concentration in small aggregates,which might protect SOC sequestration.