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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。
With the help of 18-year long-term winter wheat-summer maize experiment, the effects of fertilization on the composition of dry-loam aggregates and organic carbon content were studied. The experiment involved four treatments: no fertilization (CK); single fertilizer (NPK); organic fertilizer + chemical fertilizers combined application (MNPK); straw returning + chemical fertilizer application (SNPK). The results showed that long-term application of NPK or MNPK or SNPK had no significant effect on the size distribution of soil dry-sieved aggregates, but there was a tendency of increasing the aggregates content> 2 mm. Long-term fertilization can significantly increase soil organic carbon content and organic carbon content of various sizes of aggregates. In 0 ~ 10 cm soil layer, the content of organic carbon in different dry aggregates increased with the decrease of dry sieve aggregates, and the highest content of organic carbon in <0.25 mm dry sieve aggregates. Long-term application of organic manure, straw return to field can significantly increase 0 ~ 10 cm soil carbon in> 7 mm and 1 ~ 3 mm aggregates distribution ratio. Although fertilization had no significant effect on the distribution of dry-sieved aggregates, application of organic compounds and NPK could significantly increase the organic carbon content of small aggregates, which may have a protective effect on soil organic carbon.