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Liming represents a common agricultural practice for abating soil acidity. Nevertheless, elevated amounts of agricultural lime in Oxisols, with or without cultural residue addition, could alter soil physicochemical properties and impact soil structure. In this context, the physical, chemical, and structural behaviors of an Oxisol under the addition of lime and straw were assessed. Lime doses (0, 3.9, 7.8, and 15.6 Mg ha-1) were either applied on the surface or incorporated into the 0- to 5-cm soil layer. Straw applications followed the same procedure with quantities of 0, 4, 12, or 16 Mg ha-1. The effects on the soil profile were evaluated through physicochemical (specific surface area, ς potential, and pH), physical (density, penetration resistance, water dispersible clay, and total porosity), and micromorphological properties (surface area, volume, connectivity, size, and pore anisotropy) 1 yr after soil incubation in polyvinyl chloride cylinders 30 cm long and 14.5 cm in diameter. Lime application on the surface or into the 0- to 5-cm layer increased soil pH to values above 7.0 and the electronegative potential of soil colloid surface, promoting clay dispersion. Water-dispersed clay migrated in the soil profile, causing pore obstruction, and higher soil density and penetration resistance. In addition, excessive lime decreased specific surface area, anisotropy degree and the connectivity of the soil pore system. Straw addition promoted a slight increase of colloids electronegative potential but did not alter soil physical properties. [ABSTRACT FROM AUTHOR]

See Parker et al., "A database of soil physical properties for the Kansas Mesonet", https://doi.org/10.1002/saj2.20465. B On the cover b : Nathaniel Parker collecting undisturbed soil samples from the top 50-cm soil profile at the Clay Center station of the Kansas Mesonet. [Extracted from the article]

The management of clay-rich soils in agriculture is mainly dependent on their hydromechanical properties that govern their structural evolutions. These structural evolutions are commonly described along the shrinkage curves obtained in a laboratory. Nevertheless, the field survey needs tools of in situ investigations able to characterize the structural profile evolutions of soils through the seasons. This paper presents a method based on the cone penetration and resistivity measurement by penetrometer-salinometer coupling that was gauged in the West Marsh of the French Atlantic Coast. First, the parallel measurements of water and cone resistance (Qd) profiles in clay dominant soils, characterized by very large ranges of water content (W), allows the calculation of a Perdock's-type equation that links the Qd profiles and the shrinkage curve of the clay dominant material. Second, thanks to the homogeneity of mineralogy and cationic exchange capacity of the soil, the structure-resistivity relationship was gauged according to the Archie's law taking into account porosity (Φ), saturation index of the soil (Sat), and the resistivity of the wetting fluid (ρw). The vertical evolutions of structure, resistivity, and cone resistance can be represented in a crossed diagram showing the shrinkage curve-resistivity and Qd profile relationships. Finally, the structural profiles of soils can be modeled from the recorded resistivity and Qd profiles taking into account the ρw. [ABSTRACT FROM AUTHOR]

Management scenarios aimed at optimizing irrigation in a Sicilian vineyard characterized by a cracking clay soil irrigated with saline water were explored for seven soil profiles (Baglio 1-Baglio 7), by using the simulation model soil-water-atmosphere-plant environment (SWAP), which accounts for shrinkage and cracking. Accurate pre- diction of water content, θ, was obtained for the seven profiles by expressing the soil hydraulic properties according to the Brutsaert retention equation coupled with the hydraulic conductivity model proposed by Gardner (B-G model). A satisfactory prediction of the electrical conductivity of saturated extract (ECsat) was obtained using for the dispersivity (Ldis), a calibration value of 20 cm. Different irrigation schedulings and alternating waters of different quality were then explored as viable management options. The results showed that bypass flow determined a favorable water distribution, and that the best irrigation strategy was to make a minimum number of irrigations, by maximizing at the same time the amount of water supplied at each irrigation. Water storage in cracks was found to promote salt-leaching; neglecting cracks and bypass flow was shown to overestimate salinization. Alternating two different irrigation waters proved to be the best strategy, which could be adopted to reduce soil salinization and enhance crop transpiration. Findings concerning the role of cracks in the process of salt-leaching suggested that, under field conditions, application of a leaching solution was more efficient if the soil presented a considerable degree of cracking. [ABSTRACT FROM AUTHOR]

Land leveling is a government-subsidized, water-conserving agricultural practice common in the Mississippi River Delta region of the midsouthern United States. Though practiced to more uniformly deliver irrigation water, land leveling is a severe soil disturbance that alters the quasi-equilibrium among near-surface soil biogeochemical properties. The objectives of this study were to characterize the short-term impacts of land leveling on the magnitude, variance, and spatial variability and distributions of soil physical and biological properties and to evaluate the impact of land leveling on the relationships among soil properties in a Sharkey clay (very-fine, smectitic, thermic Chromic Epiaquert) used for irrigated soybean [GIycine max (L.) Merr.] and rice (Oryza saliva L.) production in the Mississippi Delta region of northeast Arkansas. Bulk density and clay increased (P < 0.001), while sand, silt, fungal biomass, and fungal/bacterial biomass ratio decreased (P <0.001) as a result of land leveling. Despite the effect on the fungal/bacterial biomass ratio, hence a significant alteration of the soil microbial community structure, soil bacterial biomass was unaffected by land leveling. The variance associated with silt increased (P < 0.01), while the variance for fungal biomass and the fungal/bacterial biomass ratio increased (P < 0.001) as a result of land leveling. Spatial variability and distributions of soil physical and biological properties and relationships among them were noticeably altered by land leveling. Increased variations in soil physical and biological properties as a result of any soil disturbance will make uniform field management difficult. Compared to a similar study, the magnitudes of near-surface soil physical and biological property change as a result of land leveling were lower on a clayey Vertisol than on a silt-loam Alfisol. [ABSTRACT FROM AUTHOR]