X‐ray computed tomography–measured soil pore parameters as influenced by crop rotations and cover crops

Abstract

This study examined the effect of crop rotations and winter cover crops (CCs) on near‐surface pore characteristics of a silty clay loam soil in a 27‐yr no‐till field experiment. The crop rotation treatments included a 2‐yr corn (Zea mays L.)–soybean [Glycine max L. (Merr.)] (CS) rotation and a 4‐yr corn–soybean–oat (Avena sativa L.)–winter wheat (Triticum aestivum L.) (CSOW) rotation. The subplot treatment was CC and no‐CC (fallow). Intact soil cores (7.62 by 7.62 cm) were extracted from each treatment in July 2018 from soybean plots and examined for X‐ray computed tomography (CT)‐measured pore parameters and other soil physical and hydrological properties. Data showed that, compared with fallow, the CC reduced bulk density (ρb) by 6% and increased saturated hydraulic conductivity (Ksat) and water infiltration rate (qs) by 1.5 times. Soils under CSOW rotation had 16, 14, and 4% higher values of soil organic carbon (SOC), total nitrogen (TN), and wet aggregate stability (WAS) compared with those under CS rotation, respectively. The CSOW rotation significantly (P < .05) increased number of CT‐measured pores, number of macropores (>1,000 μm diameter), coarse mesopores (226–1,000 μm diameter), macroporosity, and mesoporosity compared with the CS system. The CT‐measured total porosity, number of macropores, and macroporosity were 43, 34, and 60%, respectively, higher with CC as compared to the fallow plots. The CT‐measured pore parameters were well correlated with soil ρb, Ksat, qs, SOC, TN, and WAS. This study emphasizes that cropping systems that include diverse crop rotations (CSOW) and CC has potential to enhance SOC, pore characteristics, and associated physical and hydrological properties.

Assessing the influence of cover crop on soil water dynamics using soil moisture measurements and hydrus‐1D simulations

“…The study area has a mean annual air temperature ranging from –14.1 °C in January to 31.8 °C in July, and average precipitation of 620 mm per year. Several studies were conducted in these experimental plots to report the influence of tillage, crop rotation, and CC on soil physical and hydrological properties (e.g., Alhameid et al., 2017; Alhameid et al., 2019; Singh & Kumar, 2021; Singh et al., 2020). In the present study, we installed sensors in six plots under a 2‐yr corn–soybean rotation and no‐till system for three consecutive years (2017, 2018, and 2019), three plots with and three plots without winter CC.…”

“…Among the various management practices to improve soil physical condition, the use of cover crops (CCs) has emerged as an important component of crop rotations (Lu et al., 2000). Particularly, the use of CC in no‐till farming systems helps in building up soil organic matter and the extensive living roots of the CC improve soil structure and water infiltration (Hoorman et al., 2009; Singh et al., 2020). Cover crops such as winter rye ( Secale cereale L.) provide large quantities of surface residue as well as a soil‐stabilizing root system that could alter the hydrological properties to a deeper soil depth (Lu et al., 2000).…”

Soil matrix study using a hybrid a-Se/CMOS pixel detector for CT scanning

“…Based on previous investigations related to the study of root-soil characteristics using X-ray CT scanning [5][6][7][8][9][10], we have investigated the use of a direct conversion CMOS ROIC, the 1Mp detector, to improve the image quality and resolution of the pixel detector currently implemented in the Artis Zeego. CMOS direct charge sensors may be capable of improving the limitations caused by the ratio between sample size and resolution (voxel size), as well as the smaller resolution for larger sample sizes [20].…”

“…Previous investigations using CT for studying the root-soil interactions have highlighted challenges such as [5][6][7][8][9][10]:…”

Spatial and fractal characterization of soil hydraulic properties along a catena

“…The K sat of the soil is influenced by SOC, ρ b , and pore space and connectivity . Higher SOC and total pores as well as lower ρb values are presumed to be responsible for higher K sat at the toe slopes (Centeno et al, 2020;Singh et al, 2020). Furthermore, increased deposition and saturation at the toe slope (Garcia-Pausas et al, 2007) suggest that the soils may remain saturated for a long enough time to allow macropore flow under gravitational potential.…”