Soil porosity estimated conventionally cannot provide the spatial distribution and geometrical properties of pore networks. This on‐farm study assessed the impacts of grassland–cropland conversion on soil pore characteristics. This study aimed to quantify the microscale changes in pores near the soil surface (0–10 cm) under grasslands converted to croplands managed with a rotation of corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] (CS); an integrated crop–livestock system (ICLS) of corn–soybean–oats (Avena sativa L.)–cover crops (CCs), with livestock grazing on corn and soybean residue after harvest and on CCs; and the native grassland (NG). Intact soil cores (diameter: 76.2 mm; length: 76.2 mm) were collected in three replications from CS, ICLS, and NG areas located adjacent to each other. Soil cores were scanned via X‐ray computed tomography (CT) (pixel resolution: 0.226 by 0.226 mm; slice thickness: 0.5 mm). Soils under CS converted from NG significantly decreased CT‐measured macroporosity eightfold. However, it increased sevenfold when CS was converted to ICLS. Higher connected porosity, connection probability, and macroporosity under ICLS and NG enhanced the saturated hydraulic conductivity (K_sat) compared with CS. The soil organic carbon (SOC) stock was increased by 13% at 0‐ to 10‐cm depth, when soils under CS were converted to improved management (ICLS). Significant correlations of CT‐measured pore parameters were found with K_sat. We conclude that CS converted from grasslands degraded SOC, pores, and other hydro‐physical properties, which can be enhanced by integrating CCs and grazing on CCs and crop residues.

中文翻译：

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通过X射线计算机断层摄影术测量的草原转化为农田影响了土壤孔隙参数

常规估算的土壤孔隙度无法提供孔隙网络的空间分布和几何特性。这项农场上的研究评估了草地－农田转换对土壤孔隙特征的影响。这项研究旨在量化在由玉米（Zea mays L。）-大豆[ Glycine max（L.）Merr。]（ CS）; 玉米-大豆-燕麦的综合农作物－畜牧系统（ICLS）（燕麦）L.）–覆盖农作物（CCs），牲畜在收获后和在CCs上放牧于玉米和大豆残留物上；和原生草原（NG）。分别从彼此相邻的CS，ICLS和NG区域分三次采集完整的土壤核心（直径：76.2 mm；长度：76.2 mm）。通过X射线计算机断层扫描（CT）扫描土壤核心（像素分辨率：0.226 x 0.226 mm；切片厚度：0.5 mm）。从天然气转化为CS的土壤使CT测得的大孔隙率显着降低了八倍。但是，当CS转换为ICLS时，它增加了七倍。在ICLS和NG条件下，较高的连通孔隙度，连通概率和大孔隙度提高了饱和导水率（K _sat）与CS相比。当CS下的土壤转换为改良管理（ICLS）时，在0至10 cm深度处，土壤有机碳（SOC）储量增加了13％。发现CT测量的孔隙参数与K _sat显着相关。我们得出的结论是，从草地转换而来的CS会降低SOC，孔隙和其他水物理特性，这可以通过整合CC和放牧CC和农作物残留物来增强。