Cover crop effects on X-ray computed tomography–derived soil pore characteristics

• Published in: Journal of soils and sediments 2024, Vol.24 (1), p.111-125
• Main Authors: Kaur, Preetika, Lamba, Jasmeet, Way, Thomas R., Sandhu, Vishawjot, Balkcom, Kipling S., Sanz-Saez, Alvaro, Watts, Dexter B.
• Format: Article
• Language: English
• Subjects: Agricultural practices; Computed tomography; Contaminants; Cores; Correlation; Cotton; Cover crops; Crops; Earth and Environmental Science; Environ Risk Assess; Environment; Environmental Physics; Groundwater; Image resolution; Medical imaging; Pollution transport; Porosity; Probability theory; Research facilities; Sec 2 • Global Change; Secale cereale; Soil; Soil columns; Soil contamination; Soil dynamics; Soil management; Soil pollution; Soil porosity; Soil profiles; Soil properties; Soil Science & Conservation; Soils; Strip; Surface water; Surface-groundwater relations; Sustainable Land Use • Research Article; Tomography; Tortuosity; Trifolium incarnatum; X rays
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-023-03596-7

Purpose Cover crops have been used as an effective soil management practice to enhance soil health. However, this practice may create connected soil pore networks that can cause preferential transport of contaminants to the groundwater or surface water via subsurface flow pathways. The main objective of this study was to compare the effect of cover crops on the soil macropore characteristics in the soil profile. Methods The study was conducted on soil columns collected from E.V. Smith Research Center, Shorter, AL, USA. This study evaluated the influence of cover crop (CC) vs. no cover crop (NC) on soil pore characteristics in strip-tillage cotton ( Gossypium hirsutum L.). The cover crop treatment consisted of a mixture of cereal rye ( Secale cereale L.) and crimson clover ( Trifolium incarnatum L.). Six replicated intact undisturbed soil cores (150 mm diameter and 500 mm deep) were collected for the column study from each treatment class, i.e., CC and NC, and subjected to non-invasive X-ray computed tomography (CT) scanning, giving 0.35-mm-resolution images. The high-resolution images were analyzed in ImageJ to determine all the soil pore characteristics. Results and discussion The results of the comparison of pore characteristics as a function of treatments showed that soil columns under CC had comparatively higher values of porosity and pore number density for the top 100 mm of soil. Pore geometry metrics such as tortuosity did not show significant differences among the treatments (CC vs NC). Connection probability was significantly higher for CC in the subsurface depth class (200–400 mm). Significant correlations were also observed between CT-derived pore characteristics and root characteristics from which it can be inferred that cover crop roots influenced the X-ray CT-derived pore properties. Conclusions Cover cropping significantly impacted the macropore properties of the strip-till cotton field. This was attributed primarily to the influence of root networks on macropores. Our study’s correlations between root properties and macropore characteristics also indicated that larger root volumes were significantly correlated with complex and irregularly shaped macropores. These variables are critical for a better understanding of the flow dynamics of contaminants through the soil profile and for developing appropriate management strategies.