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Background and aims There is an urgent need to develop new high throughput approaches to phenotype roots in the field. Excavating roots to make direct measurements is labour intensive. An alternative to excavation is to measure soil drying profiles and to infer root activity. Methods We grew 23 lines of wheat in 2013, 2014 and 2015. In each year we estimated soil water profiles with electrical resistance tomography (ERT), electromagnetic inductance (EMI), penetrometer measurements and measurements of soil water content. We determined the relationships between the measured variable and soil water content and matric potential. Results We found that ERT and penetrometer measurements were closely related to soil matric potential and produced the best discrimination between wheat lines. We found genotypic differences in depth of water uptake in soil water profiles and in the extent of surface drying. Conclusions Penetrometer measurements can provide a reliable approach to comparing soil drying profiles by different wheat lines, and genotypic rankings are repeatable across years. EMI, which is more sensitive to soil water content than matric potential, and is less effective in drier soils than the penetrometer or ERT, nevertheless can be used to rapidly screen large populations for differences in root activity.

Irrigation with water containing ultrafine bubbles (UFB) promotes crop growth under environmental stress conditions. This study evaluated the changes in soil physical properties when using low-cost UFB for paddy field irrigation. An experimental paddy field was divided into eight sections, with regular agricultural (control) and UFB irrigation, and rice cultivation was conducted over three seasons. The findings indicate that the sand content, linked to the fragmentation of gravel, increased 2.6% due to UFB irrigation over two years. A one-week stirring experiment was conducted in the laboratory to observe the accelerated fragmentation of the soil particles. A UFB containing distilled water significantly decreased the sand content by 3.5–7.1% and increased the clay content by 5.3–5.6% compared to the control distilled water. The thickness of the viscous colloidal layer on the soil surface increased by a maximum of 29 mm, and the penetrometer resistance decreased with UFB irrigation under submerged paddy conditions. These results indicated that continuous irrigation with low-cost UFB water from air and agricultural water promotes soil particle fragmentation and reduces soil penetrometer resistance. This study provides valuable insights into the potential benefits and limitations of UFB irrigation in sustainable agricultural practices.

The article presents the results of measurements regarding the impact of the MHT9002HV tracked harvester on surface deformations and changing the physical parameters of the soil of three operational trails. The measurements were made in the terrain with a longitudinal slope of up to 14.9° (33.2%) and a transverse slope of up to 8.8° (17.9%). Spruce deadwood trees in mountain forest habitats were harvested. Static Eijkelkamp Penetrologger 0615SA and dynamic own design penetrometer were used to measure penetration resistance, soil samples were taken to determine bulk density, moisture content, and ground deformations on the trails were measured with a laser profilometer. A statistically significant increase in soil penetration resistance measured with penetrometers occurred for trails in the left rut at a depth of 16–20 cm. The change in the bulk density and moisture content proved statistically insignificant. The maximum ground deformation on the trails reached an average of 5.9 cm. The selection of a machine with low unit pressures (33 kPa), under the given favorable atmospheric conditions (there was a high temperature reaching 35 °C), with low soil moisture, protective organic layer of high thickness, and post-limbing residues, was optimal. The comparison of the results of the compactness measurements made with different penetrometers shows that the values obtained for the static penetrometer 0615SA are lower than those of the dynamic penetrometer of our own design. This is due to the lack of registration of high compactness in the memory of the 0615SA device. In the case of the impact penetrometer measurement, this problem does not occur, however, the presented solution does not allow performing a large number of measurements, and data processing in the case of such a simple solution is tedious. There is a need to develop a new penetrometer useful for determining soil compaction under similar difficult measurement conditions.

Root elongation in drying soil is generally limited by a combination of mechanical impedance and water stress. Relationships between root elongation rate, water stress (matric potential), and mechanical impedance (penetration resistance) are reviewed, detailing the interactions between these closely related stresses. Root elongation is typically halved in repacked soils with penetrometer resistances >0.8-2 MPa, in the absence of water stress. Root elongation is halved by matric potentials drier than about -0.5 MPa in the absence of mechanical impedance. The likelihood of each stress limiting root elongation is discussed in relation to the soil strength characteristics of arable soils. A survey of 19 soils, with textures ranging from loamy sand to silty clay loam, found that ~10% of penetration resistances were >2 MPa at a matric potential of -10 kPa, rising to nearly 50% >2 MPa at - 200 kPa. This suggests that mechanical impedance is often a major limitation to root elongation in these soils even under moderately wet conditions, and is important to consider in breeding programmes for drought-resistant crops. Root tip traits that may improve root penetration are considered with respect to overcoming the external (soil) and internal (cell wall) pressures resisting elongation. The potential role of root hairs in mechanically anchoring root tips is considered theoretically, and is judged particularly relevant to roots growing in biopores or from a loose seed bed into a compacted layer of soil.

Ball penetrometers have been employed in both centrifuge tests and field experiments for soil profile interpolation. Nevertheless, it has become apparent that the performance of the ball penetrometer in centrifuge tests significantly deviates from that in field tests. In this study, a more comprehensive analysis utilizing the larger deformation finite element method was undertaken to gain deeper insights into the behavior of ball penetrometers when used in nonhomogeneous clay within the centrifuge testing environment. This investigation accounts for the influence of the unique scale and shaft ratio of the ball penetrometer in centrifuge tests. The numerical model developed in this study was rigorously validated against previously published data, demonstrating a high degree of agreement. Subsequently, a parametric study was conducted to investigate potential influencing factors. As a result, a novel method for quantifying the bearing capacity factor was proposed. This method offers the promise of obtaining more precise data regarding the continuous shear strength in centrifuge tests, thereby providing valuable guidance for soil profile determination within this experimental setting.

Brassica carinata, a nonfood oilseed crop, is used to produce renewable fuels because of its high oil content and favorable fatty acid profile. Production in the southeastern United States is relatively new, and information on agronomic management practices to optimize growth and yield is limited. Since optimal seeding rate may depend on the land preparation method for this small‐seeded crop, a study was conducted to evaluate the effect of tillage system (conventional, no‐till, broadcast‐disc, and ripper‐roller) and seeding rate (1.12, 5.60, 10.09, and 14.57 kg seed ha−1) on the performance of B. carinata. A randomized complete block design with a strip‐plot restriction on randomization and four replications was implemented in Headland, AL, Jay, FL, and Quincy, FL, over five site‐years during the 2017–2018 and 2018–2019 growing seasons. Data were collected on soil residue cover; plant population; soil penetrometer resistance and moisture; biomass (including carbon and nitrogen); stalk diameter; yield and yield components; seed oil, protein, and glucosinolates concentration; and oil composition. Soil penetrometer resistance was significantly affected by tillage system, with the ripper‐roller consistently having the lowest penetration resistance values across all site‐years. Ripper‐roller tillage had the highest oil content and lowest protein and glucosinolate contents. Yield response to tillage system was variable. Among seeding rate treatments, yield was lowest at 1.12 kg seed ha−1 and similar among 5.60, 10.09, and 14.57 kg seed ha−1 at all site‐years. There was no tillage by seeding rate interaction for yield. Results indicate that among seeding rate treatments used, 5.6 kg seed ha−1 rate was optimal at all site‐years regardless of land preparation method and is thus the recommended seeding rate for commercial carinata production in the Southeastern United States. Carinata commercialization was first introduced to the Southeastern United States in 2014 to be grown as a winter crop to produce jet fuel, seed meal, and other high‐value co‐products. However, several agronomic management issues related to production emerged, among which are tillage and seeding rates. These issues require resolution. A study was conducted over five site‐years to evaluate the effect of tillage system (conventional, no‐till, broadcast‐disc, and ripper‐roller) and seeding rate (1.12, 5.60, 10.09, and 14.57 kg seed ha−1) on the performance of carinata. Results indicate that among seeding rate treatments used, 5.6 kg seed ha−1 rate was optimal at all site‐years regardless of land preparation method.

This research introduces the development of a sequential limit analysis (SLA) method in OPTUM. The plane-strain analysis capability of the original SLA has been extended to encompass both plane-strain and axis-symmetric problems, and the usability has been expanded to a broader spectrum of users. Moreover, refinements in addressing nodal velocities during soil collapse under gravity, specifically in scenarios featuring a stiff soil berm leading to slope instability, have been implemented, to enable proper modelling of more extreme conditions and complex model geometries. A detailed validation has been made against various penetration problems. It is revealed that SLA simulations can be executed with displacement increments at the order of 1% of the characteristic size of the object. In addition, a succinct parametric study on ball penetration is presented. Penetration resistance with strain softening is reduced by up to 34.5% compared to the non-softening case. An equivalent plastic strain factor was adopted to enhance the accuracy of measuring soil strength through ball penetrometer tests. The enhanced SLA method could also serve as a powerful tool for analysing large deformation soil-structure interaction problems for piles, spudcans, and cone / ball penetrometers in offshore engineering.

The seabed surface provides habitat for abundant and diverse fauna, whose burrowing activities have been shown to modify geotechnical properties of surface sediments. Whether these impacts affect geotechnical properties on larger scales of traditional measurements has not been well studied. This study represents an initial attempt to assess whether infaunal activity affects seabed properties on a scale relevant for, and therefore, detectable in portable free fall penetrometer measurements. Specifically, we examine sediment strength profiles of the upper 10–70 cm of sandy (poorly graded sand and muddy sand) seabed sediments in Mobile Bay, Alabama, USA, hypothesizing that infauna create heterogeneity in sediment structure that would lead to variability in PFFP vertical profiles as well as among replicate measurements at a site. Sediments were composed predominantly of sands, with only 17% of the sites featuring sand contents < 97% and median grain sizes ranging from 0.0987 to 0.3457 mm. Sediment strength generally decreased with a decreasing sand content, but variability was not explained by sand content alone. PFFP impacts in sandier sites (> 97% sand) were limited to the surface few cm, but considerable vertical and spatial variability in muddy sands and lower strength at sites with abundant burrowing infauna suggest that infaunal activities may affect PFFP measurements in these sediments.

Background Sugarcane ( Saccharum spp. ) is the core crop for sugar and bioethanol production over the world. A major problem in sugarcane production is stalk lodging due to weak mechanical strength. Rind penetrometer resistance (RPR) and breaking force are two kinds of regular parameters for mechanical strength characterization. However, due to the lack of efficient methods for determining RPR and breaking force in sugarcane, genetic approaches for improving these traits are generally limited. This study was designed to use near-infrared spectroscopy (NIRS) calibration assay to accurately assess mechanical strength on a high-throughput basis for the first time. Results Based on well-established laboratory measurements of sugarcane stalk internodes collected in the years 2019 and 2020, considerable variations in RPR and breaking force were observed in the stalk internodes. Following a standard NIRS calibration process, two online models were obtained with a high coefficient of determination ( R 2 ) and the ratio of prediction to deviation (RPD) values during calibration, internal cross-validation, and external validation. Remarkably, the equation for RPR exhibited R 2 and RPD values as high as 0.997 and 17.70, as well as showing relatively low root mean square error values at 0.44 N mm −2 during global modeling, demonstrating excellent predictive performance. Conclusions This study delivered a successful attempt for rapid and precise prediction of rind penetrometer resistance and breaking force in sugarcane stalk by NIRS assay. These established models can be used to improve phenotyping jobs for sugarcane germplasm on a large scale.

Large deformation finite element simulations of the dynamic penetration of underwater free-fall spherical penetrometers into clay are carried out using the coupled Eulerian–Lagrangian approach. Two undrained total stress analysis models are constructed and applied to simulate four well-documented centrifuge tests of sphere penetration. Model A is a new model that simulates both the free-fall process in water and the penetration process in clay. Model B, as usual, simulates only the penetration process in clay in the absence of overlying water. The simulation of the free-fall process in water is validated against an analytical solution and calibrated against the measured impact velocities of the tested spheres upon hitting the clay surface. The ability of the two models to predict the dynamic penetration behavior in clay is evaluated by comparing their results with the centrifuge test results. Model A provides a better prediction of the penetration behavior than Model B. Fully open, partially closed, and fully closed cavities formed by the passages of the sphere and water were reproduced by Model A. The water flow in the wake of the penetrating sphere is shown to have an important influence on the deformations of the clay surface and cavity wall.