Applying fertilizers on a long-term basis can promote the accumulation of soil organic matter and increase soil aggregation. The effects of organic and inorganic fertilizers on soil structure have manifested as different morphological characteristics for different soil types. To quantify the three-dimensional (3D) pore structure of soil cores after long-term fertilization, we collected cinnamon soil (Chromic Luvisol) aggregates and 2 cm x 2 cm x 2 cm soil cores from a long-term fertilization field trial beginning in 1989. The treatment groups included no fertilization (CK), inorganic fertilization (NPK) and organic fertilization (OF). Synchrotron radiation-based X-ray microcomputer tomography (SR-mu CT) and digital image analysis were used to determine the soil core structure. The results showed that the long-term practices of OF treatment increased the stability of wet aggregates. Combined visualization of the soil structure and morphological parameters consistently revealed that the soil pore systems under OF treatment were more connected and multilevel than those under the CK treatment after 22 years. The soil pore structures under the CK and NPK treatments were similar but significantly different from the structure under the OF treatment.
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机译:长期施肥可以促进土壤有机质的积累,增加土壤团聚。有机肥和无机肥对土壤结构的影响表现为不同土壤类型不同的形态特征。为了量化长期施肥后土壤核心的三维(3D)孔隙结构,我们从1989年开始的长期施肥田间试验中收集了肉桂土(Chromic Luvisol)团聚体和2 cm x 2 cm x 2 cm土壤核心。处理组包括不施肥(CK)、无机施肥(NPK)和有机施肥(OF)。采用基于同步辐射的X射线微机断层扫描(SR-mu CT)和数字图像分析技术对土核结构进行了测定。结果表明,长期的OF处理提高了湿骨料的稳定性。土壤结构和形态参数的综合可视化结果一致表明,22年后,OF处理下的土壤孔隙系统比CK处理下的土壤孔隙系统更具连通性和多层次性。CK和NPK处理下的土壤孔隙结构与OF处理的土壤孔隙结构相似,但差异显著。
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