亚热带几种典型稻田与旱作土壤中外源输入秸秆的分解与转化差异
发布时间：2019-02-16 16:01
【摘要】：选取亚热带四种典型母质(花岗岩风化物、第四纪红色粘土、板页岩风化物、近代河流沉积物)发育的稻田土壤,以毗邻的旱作土壤为对比,通过室内模拟培养试验研究45%田间持水量(WHC)条件下稻田和旱作土壤中外源输入秸秆矿化和转化的特征与差异。结果表明:在180 d的培养期内,所选4种稻田土壤中外源输入秸秆的累积矿化率(18%—21%)均显著低于对应的旱作土壤(21%—28%),外源秸秆的输入对土壤原有有机碳矿化的激发效应也是以稻田土壤(5%—30%)明显低于对应的旱作土壤(17%—65%)。外源秸秆在土壤中的分解产物主要向颗粒有机碳(POC)和铁铝结合态有机碳(Fe/Al-OC)分配,分配比例分别为9%—21%和12%—24%,其次为腐殖质碳(HMC)(11%—15%),而向微生物生物量碳(MBC)和溶解性有机碳(DOC)分配的比例极小,分别仅为2%—7%和0.1%-0.7%。与旱作土壤相比,稻田土壤中外源秸秆的分解产物向POC、Fe/Al-OC和MBC分配的比例较高,分别为15%—21%、17%—24%和6%—7%,而旱作土壤为9%—17%、13%—18%和2%—4%。此外,外源秸秆分解产物向2000—250μm水稳性粗团聚体分配的比例也以稻田土壤(10%—13%)高于旱作土壤(6%—7%),其它粒径中稻田与对应的旱作土壤之间并无显著差异。本研究结果说明,稻田土壤中外源输入秸秆的矿化率低于旱作土壤的现象在不同母质类型的土壤中可能普遍存在,这可能与稻田土壤中外源秸秆分解产物受水稳性团聚体的物理保护、与氧化铁铝的化学键合以及向有机碳稳定组分的分配作用较强有关,从而贡献于稻田土壤较高的有机碳积累。
[Abstract]:Four typical parent materials (granite weathering, Quaternary red clay, plate shale weathering, modern river sediment) developed in the subtropics were selected and compared with adjacent dryland soils. The characteristics and differences of exogenous straw mineralization and transformation in paddy field and dryland soil under the condition of 45% field water holding capacity (WHC) were studied by simulated cultivation in laboratory. The results showed that the cumulative mineralization rate (18-21%) of exogenous straw in the selected four paddy soils was significantly lower than that in the corresponding dryland soil (21-28%) during the 180 d culture period. The stimulation effect of exogenous straw on the mineralization of soil organic carbon was also significantly lower in paddy soil (5- 30%) than in the corresponding dryland soil (17-65%). The decomposition products of exogenous straw in soil were mainly distributed to particulate organic carbon (POC) and iron-aluminum bound organic carbon (Fe/Al-OC), with the distribution ratios of 9- 21% and 12-24%, respectively. The next was humus carbon (HMC) (11-15%), but the proportion to microbial biomass carbon (MBC) and dissolved organic carbon (DOC) was very small, which was only 2 -7% and 0.1% -0.7%, respectively. Compared with dry soil, the ratio of decomposition products of exogenous straw to POC,Fe/Al-OC and MBC in paddy soil was 15-21%, 17-24% and 6-7%, respectively, while that in dryland soil was 9-17%. 13-18% and 2-4%. In addition, the proportion of decomposition products of exogenous straw to water-stable coarse aggregates of 2000-250 渭 m was also higher in paddy soil (10- 13%) than in dryland soil (6- 7%). There was no significant difference between the paddy field and the corresponding dry soil in other particle sizes. The results show that the mineralization rate of exogenous straw in paddy soil is lower than that in dry soil, which may be widespread in different parent material types of soil. This may be related to the physical protection of exogenous straw decomposition products from water-stable aggregates in paddy soils, the chemical bonding of iron and aluminum oxide and the distribution of organic carbon stable components. Thus contribute to the higher accumulation of organic carbon in paddy soil.
【作者单位】： 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室;中国科学院大学;
【基金】：国家自然科学基金项目(41371252,41430860,41671242) 国家重点研发计划项目(2016YFD0300902)
【分类号】：S141;S153
[Abstract]:Four typical parent materials (granite weathering, Quaternary red clay, plate shale weathering, modern river sediment) developed in the subtropics were selected and compared with adjacent dryland soils. The characteristics and differences of exogenous straw mineralization and transformation in paddy field and dryland soil under the condition of 45% field water holding capacity (WHC) were studied by simulated cultivation in laboratory. The results showed that the cumulative mineralization rate (18-21%) of exogenous straw in the selected four paddy soils was significantly lower than that in the corresponding dryland soil (21-28%) during the 180 d culture period. The stimulation effect of exogenous straw on the mineralization of soil organic carbon was also significantly lower in paddy soil (5- 30%) than in the corresponding dryland soil (17-65%). The decomposition products of exogenous straw in soil were mainly distributed to particulate organic carbon (POC) and iron-aluminum bound organic carbon (Fe/Al-OC), with the distribution ratios of 9- 21% and 12-24%, respectively. The next was humus carbon (HMC) (11-15%), but the proportion to microbial biomass carbon (MBC) and dissolved organic carbon (DOC) was very small, which was only 2 -7% and 0.1% -0.7%, respectively. Compared with dry soil, the ratio of decomposition products of exogenous straw to POC,Fe/Al-OC and MBC in paddy soil was 15-21%, 17-24% and 6-7%, respectively, while that in dryland soil was 9-17%. 13-18% and 2-4%. In addition, the proportion of decomposition products of exogenous straw to water-stable coarse aggregates of 2000-250 渭 m was also higher in paddy soil (10- 13%) than in dryland soil (6- 7%). There was no significant difference between the paddy field and the corresponding dry soil in other particle sizes. The results show that the mineralization rate of exogenous straw in paddy soil is lower than that in dry soil, which may be widespread in different parent material types of soil. This may be related to the physical protection of exogenous straw decomposition products from water-stable aggregates in paddy soils, the chemical bonding of iron and aluminum oxide and the distribution of organic carbon stable components. Thus contribute to the higher accumulation of organic carbon in paddy soil.
【作者单位】： 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室;中国科学院大学;
【基金】：国家自然科学基金项目(41371252,41430860,41671242) 国家重点研发计划项目(2016YFD0300902)
【分类号】：S141;S153
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