Assessing the influence of the rhizosphere on soil hydraulic properties using X-ray computed tomography and numerical modelling
نویسندگان
چکیده
Understanding the dynamics of water distribution in soil is crucial for enhancing our knowledge of managing soil and water resources. The application of X-ray computed tomography (CT) to the plant and soil sciences is now well established. However, few studies have utilized the technique for visualizing water in soil pore spaces. Here this method is utilized to visualize the water in soil in situ and in three-dimensions at successive reductive matric potentials in bulk and rhizosphere soil. The measurements are combined with numerical modelling to determine the unsaturated hydraulic conductivity, providing a complete picture of the hydraulic properties of the soil. The technique was performed on soil cores that were sampled adjacent to established roots (rhizosphere soil) and from soil that had not been influenced by roots (bulk soil). A water release curve was obtained for the different soil types using measurements of their pore geometries derived from CT imaging and verified using conventional methods, such as pressure plates. The water, soil, and air phases from the images were segmented and quantified using image analysis. The water release characteristics obtained for the contrasting soils showed clear differences in hydraulic properties between rhizosphere and bulk soil, especially in clay soil. The data suggest that soils influenced by roots (rhizosphere soil) are less porous due to increased aggregation when compared with bulk soil. The information and insights obtained on the hydraulic properties of rhizosphere and bulk soil will enhance our understanding of rhizosphere biophysics and improve current water uptake models.
منابع مشابه
Assessing the influence of the rhizosphere on soil hydraulic properties using X - ray 1 Computed Tomography and numerical modelling
Short title for page headings: Influence of the rhizosphere on soil hydraulic properties 16 17 Short statement: Using non-destructive imaging techniques and numerical modelling we 18 quantify differences in hydraulic and structural properties of bulk and rhizosphere soil for 19 sand and clay loam soils. 20 21 22 2 1. Abstract 23 Understanding the dynamics of water distribution in soil is crucia...
متن کاملAssessment of X-Ray Crosstalk in a Computed Tomography Scanner with Small Detector Elements Using Monte Carlo Method
Introduction: Crosstalk is a leakage of X-ray or light produced in a matrix of X-ray detectors or array of photodiodes in one element to other elements affecting on image contrast and spatial resolution. In this study, we assessed X-ray crosstalk in a computed tomography (CT) scanner with small detector elements to estimate the effect of various parameters such as X-ray tube voltage, detector e...
متن کاملThree dimensional quantification of soil hydraulic properties using X - ray Computed 1 Tomography and image based modelling
متن کامل
Image-based modelling of nutrient movement in and around the rhizosphere
In this study, we developed a spatially explicit model for nutrient uptake by root hairs based on X-ray computed tomography images of the rhizosphere soil structure. This work extends our previous work to larger domains and hence is valid for longer times. Unlike the model used previously, which considered only a small region of soil about the root, we considered an effectively infinite volume ...
متن کاملImpact of Photon Spectra on the Sensitivity of Polymer Gel Dosimetry by X-Ray Computed Tomography
Introduction: The purpose of the current study was to investigate the effect of X-ray spectra on the sensitivity of a polymer gel dosimeter imaged with a conventional computed tomography (CT) scanner. Material and Methods: The whole process of CT imaging of an irradiated polymer gel was simulated by MCNPX Monte Carlo (MC) code. The imaging of polyacrylamide gel was accomplished by means of a co...
متن کامل