Download or read book Processes and Effects of Root induced Changes to Soil Hydraulic Properties written by Craig Anthony Scanlan and published by . This book was released on 2009 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated abstract] Root-induced changes to soil hydraulic properties (SHP) are an essential component in understanding the hydrology of an ecosystem, and the resilience of these to climate change. However, at present our capacity to predict how roots will modify SHP and the consequences of this is limited because our knowledge of the processes and effects are highly fragmented. Also, current models used to investigate the relationship between plants and root-induced changes to SHP are based on empirical relationships which have limited applicability to the various and often contrasting ecosystems that occur. This thesis focuses specifically on the quantifying the processes by which roots modify SHP and developing models that can predict changes to these and the water balance. Both increase and decreases in saturated hydraulic conductivity have been attributed to the presence of roots. In general, decreases occur when the root system is relatively young, and increases occur when the roots senesce and begin to decay, creating voids for water flow. The evidence available suggests that the change in pore geometry created by roots is the dominant process by which roots modify SHP because they are more permanent and of a greater magnitude than changes to fluid properties or soil structure. We first quantified the effects of wheat roots on SHP of a coarse sand with a laboratory experiment where we measured changes in both SHP and the root system at 3, 5, 7 and 9 weeks after sowing (weeks). ... The main message that can be drawn from this thesis is that root-induced changes to SHP are dynamic, and dependent upon the combination of soil texture, connectivity of root-modified pores and the ratio of root radius to pore radius. Consequently, root-induced changes to the water balance have the same dependencies. The work in this thesis provides a significant first step towards improving our capacity to predict how roots modify soil hydraulic properties. By defining the range for the parameters used to predict how the soil is modified by roots, we are able to make quantitative assessments of how a property such as hydraulic conductivity will change for a realistic circumstance. Also , for the first time we have measured changes in soil hydraulic properties and roots and have been able to establish why a rapid change from a root-induced decrease to increase in Ks occurred. The link between physiological stage of the root system, and the changes that are likely to occur has implications for understanding how roots modify SHP: it may provide an effective tool for predicting when the switch from a decrease to increase occurs. Further work is required to test the validity of the assumptions we have made in our models that predict changes to SHP. While we have endeavoured to define the parameter space for those parameters that we have introduced, there is still some uncertainty about the connectivity of root-modified pores. Also, the parameterisation of the soil domain with roots is based upon work that measures 'fine' roots only which may not provide a true representation of the effect trees and perennial shrubs have on SHP. It is inevitable that root-induced changes to SHP will affect the fate of solutes in the soil, and temporal dynamics of root-induced changes to these may be particularly important for the timing of nutrient and pesticide leaching.

Download or read book Plant induced soil changes Processes and feedbacks written by N. van Breemen and published by Springer Science & Business Media. This book was released on 1998-08-31 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book by soil scientists and ecologists reviews how and why plants influence soils. Topics include effects on mineral weathering, soil structure, and soil organic matter and nutrient dynamics, case studies of soil-plant interactions in specific biomes and of secondary chemicals influencing nutrient cycling, the rhizosphere, and potential evolutionary consequences of plant-induced soil changes. This is the first volume that specifically highlights the effects of plants on soils and their feedbacks to plants. By contrast, other texts on soil-plant relationships emphasize effects of soil fertility on plants, following the strongly agronomic character of most research in this area. The aspects discussed in this volume are crucial for understanding terrestrial ecosystems, biogeochemistry and soil genesis. The book is directed to terrestrial ecologists, foresters, soil scientists, environmental scientists and biogeochemists, and to students following specialist courses in these fields.

Download or read book Root induced Compaction and Its Effects on Soil Microstructure and Soil Hydraulic Properties Using X ray Micro tomography and Numerical Simulations written by Jazmín Estefanía Aravena Ibáñez and published by . This book was released on 2011 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil is a challenging environment where resources, such as water, nutrients and air, are scarce and patchy. Plants and soil microorganisms have limited ability to move toward nutrient-enriched zones, compared with animals. Plants and roots have evolved to adapt and influence their physical environment as a way to create favorable conditions for its development. On the other hand, the structure of the soil controls its ability to receive, store and transmit water, to cycle carbon and nutrients, and to disperse anthropogenic and natural contaminants. As roots grow, soil structure changes; the pressure exerted produces a decrease in soil porosity and an increase in soil density, creating complex soil-root interactions. The scales of interest in the study of soil structure range from angstroms to kilometers. To study processes such as plant growth, root penetration, storage of water, and movement of nutrients, the most relevant scales range from microns to centimeters. Recent advances in X-ray micro-tomography (XMT) imaging have allowed the study of rhizosphere on spatial scale hitherto unreachable. This dissertation investigates utilization of XMT to study root-induced compaction on soil micro-structure and its effect on soil hydraulic properties. The current state of the art in soil-plant-root interactions using XMT is presented. Techniques to improve sensitivity of XMT images when roots are being scanned, are discussed. Feasibility of various segmentation techniques and examples of their use to quantify soil properties are addressed. XMT data quantification is then used in the study to feed numerical flow models. At bulk-scale, soil compaction has been associated with decrease in porosity and hydraulic conductivity and thus a reduction in soil productivity and fertility. However, at the aggregate scale, this study shows that natural root-induced compaction increases contact areas between aggregates, which may lead to an increase in unsaturated hydraulic conductivity of the soil adjacent to the roots. An analytical model to estimate the effect aggregate compaction on its effective hydraulic conductivity was developed. It was found that the effective hydraulic conductivity of a pair of aggregates, undergoing uniaxial stress, increased following a non-linear relationship as inter-aggregate contact area increased. Additionally, this study presents numerical modeling using actual XMT images of aggregated soil around a root surrogate to demonstrate how root-induced deformation increases unsaturated water flow towards the root, providing insight into the growth and water uptake patterns of roots in natural soils. Finally, this study presents a novel procedure that allowed coupling mechanical induced compaction with fluid flow simulation to model root-induced compaction in the rhizosphere. XMT images were used to describe in detail the rhizosphere microstructure. Then, finite element simulations were used to study the effect of an expanding root on root water uptake. The effect of increase aggregate connectivity, increase in effective hydraulic conductivity, root-soil contact area, and increase in local and global hydraulic gradient were evaluated. These results contribute to a better understanding of soil-waterroot interactions.

Download or read book Soil Physics with Python written by Marco Bittelli and published by . This book was released on 2015 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: This innovative study presents concepts and problems in soil physics, and provides solutions using original computer programs. It provides a close examination of physical environments of soil, including an analysis of the movement of heat, water and gases. The authors employ the programminglanguage Python, which is now widely used for numerical problem solving in the sciences. In contrast to the majority of the literature on soil physics, this text focuses on solving, not deriving, differential equations for transport. Using numerical procedures to solve differential equations allowsthe solution of quite difficult problems with fairly simple mathematical tools. Numerical methods convert differential into algebraic equations, which can be solved using conventional methods of linear algebra. Each chapter introduces a soil physics concept, and proceeds to develop computer programsto solve the equations and illustrate the points made in the discussion.Problems at the end of each chapter help the reader practise using the concepts introduced. The text is suitable for advanced undergraduates, graduates and researchers of soil physics. It employs an open source philosophy where computer code is presented, explained and discussed, and provides thereader with a full understanding of the solutions. Once mastered, the code can be adapted and expanded for the user's own models, fostering further developments. The Python tools provide a simple syntax, Object Oriented Programming techniques, powerful mathematical and numerical tools, and a userfriendly environment.

Download or read book The Root Systems in Sustainable Agricultural Intensification written by Zed Rengel and published by John Wiley & Sons. This book was released on 2021-04-22 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore an in-depth and insightful collection of resources discussing various aspects of root structure and function in intensive agricultural systems The Root Systems in Sustainable Agricultural Intensification delivers a comprehensive treatment of state-of-the-art concepts in the theoretical and practical aspects of agricultural management to enhance root system architecture and function. The book emphasizes the agricultural measures that enhance root capacity to develop and function under a range of water and nutrient regimes to maximize food, feed, and fibre production, as well as minimize undesirable water and nutrient losses to the environment. This reference includes resources that discuss a variety of soil, plant, agronomy, farming system, breeding, molecular and modelling aspects to the subject. It also discusses strategies and mechanisms that underpin increased water- and nutrient-use efficiency and combines consideration of natural and agricultural systems to show the continuity of traits and mechanisms. Finally, the book explores issues related to the global economy as well as widespread social issues that arise from, or are underpinned by, agricultural intensification. Readers will also benefit from the inclusion of: A thorough introduction to sustainable intensification, including its meaning, the need for the technology, components, and the role of root systems Exploration of the dynamics of root systems in crop and pasture genotypes over the last 100 years Discussion of the interplay between root structure and function with soil microbiome in enhancing efficiency of nitrogen and phosphorus acquisition Evaluation of water uptake in drying soil, including balancing supply and demand Perfect for agronomists, horticulturalists, plant and soil scientists, breeders, and soil microbiologists, The Root Systems in Sustainable Agricultural Intensification will also earn a place in the libraries of advanced undergraduate and postgraduate students in this field who seek a one-stop reference in the area of root structure and function.

Download or read book Root Methods written by A.L. Smit and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive review of all modern methods for plant root research, both in the field and in the laboratory. It covers the effects of environmental interactions with root growth and function, focussing in particular on the assessment of root distribution and dynamics. It also describes and discusses the processing of root observations, analysis and modelling of root growth and architecture, root-image analysis, computer-assisted tomography and magnetic resonance imaging. Furthermore, a survey of the application of isotope techniques in root physiology is given.

Download or read book Encyclopedia of Agrophysics written by Jan Gliński and published by Springer Science & Business Media. This book was released on 2011-06-07 with total page 1075 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Encyclopedia of Agrophysics will provide up-to-date information on the physical properties and processes affecting the quality of the environment and plant production. It will be a "first-up" volume which will nicely complement the recently published Encyclopedia of Soil Science, (November 2007) which was published in the same series. In a single authoritative volume a collection of about 250 informative articles and ca 400 glossary terms covering all aspects of agrophysics will be presented. The authors will be renowned specialists in various aspects in agrophysics from a wide variety of countries. Agrophysics is important both for research and practical use not only in agriculture, but also in areas like environmental science, land reclamation, food processing etc. Agrophysics is a relatively new interdisciplinary field closely related to Agrochemistry, Agrobiology, Agroclimatology and Agroecology. Nowadays it has been fully accepted as an agricultural and environmental discipline. As such this Encyclopedia volume will be an indispensable working tool for scientists and practitioners from different disciplines, like agriculture, soil science, geosciences, environmental science, geography, and engineering.

Download or read book Persistence of Subsoiling Effects on the Soil Physical and Hydraulic Properties in a Reconstructed Soil written by Christina C. Hebb and published by . This book was released on 2015 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface mining is one of the most significant forms of anthropogenic disturbance to natural and managed ecosystems. In Alberta, mining disturbs large areas in the Mixedwood Boreal natural region and recovery is often slow because of poor soil quality, specifically the high degree of compaction. Soil compaction, caused by repeated traffic of heavy machinery during soil reconstruction of surface mined lands, hinders the re-establishment of vegetation. Compaction causes changes to soil physical properties such as increased bulk density and reduced macroporosity which reduce soil infiltration capacity, drainage and water holding capacity. The disruption of the soil water balance as a result of these compaction-induced changes to the soil further negatively effects the chemical and biological functioning in the soil because of poor aeration. In compacted forest soils, subsoiling with heavy-duty rip ploughs has been shown to be an effective method at ameliorating compaction by breaking up large compacted layers, into smaller aggregates and peds which significantly increases macroporosity, infiltration, drainage and aeration. The main objective of this research is to quantify any medium-term (~ 4 yrs) benefits of subsoiling with a heavy-duty rip plough on reconstructed soil at a coal mine. In 2010, an experimental research site was established at the Genesee Prairie Mine, 70 km west of Edmonton to investigate the potential for compaction amelioration using a McNabb winged subsoiler D7R XR to a 60 cm depth. Results showed that medium-term effects of ripping are variable with depth. Ripping effects on pore size distribution, saturated hydraulic conductivity, and bulk density were most pronounced in the 15-20 cm depth. Infiltration rates were increased by ripping which is expected to reduce hydraulic barriers at the soil surface. Evidence suggests non-ripped surface layers (5-10 cm depth) showed improvements in soil properties (bulk density, saturated hydraulic conductivity) as a result of natural processes (i.e., plant root expansion and drying-shrinkage). Over time, it appears that the effects of ripping have decreased, with a simultaneous improvement in non-ripped soils.

Download or read book Advanced Unsaturated Soil Mechanics written by Charles W.W. Ng and published by CRC Press. This book was released on 2024-10-24 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unsaturated soil is a three-phase material that is ubiquitous on the Earth’s surface and exhibits complex behaviour, which becomes more complex in response to the Earth’s changing climate and increasing engineering activities. This is because the former affects its moisture and temperature conditions significantly and the latter governs its stress state and suction condition. This book is designed to meet the increasing challenges of climate change and engineering activities by covering the mechanics and engineering of unsaturated soil in a logical manner. It comprises four major parts: Water retention and flow characteristics Shear strength and stiffness at various temperatures State-dependent elasto-plastic constitutive modelling Field monitoring and engineering applications This second edition uniquely covers fundamental topics on unsaturated soil that are not covered in other similar books, including: the state- dependency of soil- water retention behaviour and water permeability functions, such as dependence on engineering activities small strain stiffness considering the influence of wetting- drying cycles and recent suction history, such as that due to climate change suction effects on dilatancy and peak shear strength cyclic thermal effects on soil behaviour state- dependent elastoplastic constitutive modelling of monotonic and cyclic behaviour engineering applications such as the South-to-North Water Transfer Project; an earthen landfill cover system devoid of geomembrane in the Xiaping landfill, Shenzhen; and a 15-m-deep multi- propped excavation in Tianjin, China

Download or read book Unsaturated Soils Research Applications written by Adrian R. Russell and published by CRC Press. This book was released on 2020-09-23 with total page 907 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the contributions to the Second European Conference on Unsaturated Soils, E-UNSAT 2012, held in Napoli, Italy, in June 2012, and includes more than one hundred papers, addressing three thematic areas: experimental, modelling, and engineering.

Download or read book Guidelines Land Evaluation for Irrigated Agriculture written by Food and Agriculture Organization of the United Nations. Soil Resources, Management, and Conservation Service and published by . This book was released on 1985 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plant Soil Slope Interaction written by Charles Wang Wai Ng and published by CRC Press. This book was released on 2019-07-01 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: This inter-disciplinary book provides the latest advanced knowledge of plant effects on vegetated soil properties such as water retention capability, water permeability function, shear strength, slope hydrology, movements and failure mechanisms, and applies this knowledge to the solution of slope stability problems. It is the first book to cover in detail not only the mechanical effects of root reinforcement but more importantly the hydrological effects of plant transpiration on soil suction, soil shear strength, and water permeability. The book also offers a fundamental understanding of soil-plant-water interaction. Analytical equations are provided for predicting the combined hydrological and mechanical effects of plant roots on slope stability. A novel method is also given for simulating transpiration-induced suction in a geotechnical centrifuge. Application of this method to the study of the failure mechanisms of vegetated slopes reinforced by roots with different architectures is discussed. This book is essential reading for senior undergraduate and postgraduate students as well as researchers in civil engineering, geo-environmental engineering, plant ecology, agricultural science, hydrology and water resources. It also provides advanced knowledge for civil engineers seeking "green" engineering solutions to combat the negative impact of climate change on the long-term engineering sustainability of infrastructure slopes. Professionals other than civil engineers, such as ecologists, agriculturists, botanists, environmentalists, and hydrologists, would also find the book relevant and useful.

Download or read book Soil Water Root Processes written by Stephen H. Anderson and published by John Wiley & Sons. This book was released on 2020-01-22 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid advances in tomography and imaging techniques and their successful application in soil and plant science are changing our sciences today. Many more articles using imaging and tomography are being published currently compared to 20 years ago. Soil–Water–Root Processes: Advances in Tomography and Imaging is a unique assemblage of contributions exploring applications of imaging and tomography systems in soil science—it provides an updated collection of X-ray computed tomography, synchrotron microtomography, neutron imaging, magnetic resonance imaging, geophysical imaging tools, and other tomography techniques for evaluating soils and roots. Exciting new procedures and applications have been developed, with the promise to propel forward our understanding of soil and plant properties and processes.

Download or read book Unsaturated Soils Research Applications written by Nasser Khalili and published by CRC Press. This book was released on 2014-06-05 with total page 1872 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unsaturated Soils: Research and Applications contains 247 papers presented at 6th International Conference on Unsaturated Soils (UNSAT2014, Sydney, Australia, 2-4 July 2014). The two volumes provide an overview of recent experimental and theoretical advances in a wide variety of topics related to unsaturated soil mechanics:- Unsaturated Soil Behavi

Download or read book Mycorrhizal Mediation of Soil written by Nancy Collins Johnson and published by Elsevier. This book was released on 2016-11-03 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mycorrhizal Mediation of Soil: Fertility, Structure, and Carbon Storage offers a better understanding of mycorrhizal mediation that will help inform earth system models and subsequently improve the accuracy of global carbon model predictions. Mycorrhizas transport tremendous quantities of plant-derived carbon below ground and are increasingly recognized for their importance in the creation, structure, and function of soils. Different global carbon models vary widely in their predictions of the dynamics of the terrestrial carbon pool, ranging from a large sink to a large source. This edited book presents a unique synthesis of the influence of environmental change on mycorrhizas across a wide range of ecosystems, as well as a clear examination of new discoveries and challenges for the future, to inform land management practices that preserve or increase below ground carbon storage. - Synthesizes the abundance of research on the influence of environmental change on mycorrhizas across a wide range of ecosystems from a variety of leading international researchers - Focuses on the specific role of mycorrhizal fungi in soil processes, with an emphasis on soil development and carbon storage, including coverage of cutting-edge methods and perspectives - Includes a chapter in each section on future avenues for further study

Download or read book Effect of Root Activity on Soil Hydraulic Properties written by B. A. Riseley and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optimization of Plant Nutrition written by M.A. Fragoso and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world-wide shortage of plant production menacing the survival of many people demands for more and better research, particularly on how to increase food and where it is most needed. Major problems of international concern for the scientific community are the availability in soil media of macro and micro nutrients and the efficiency of nutrient uptake by plant roots, the interactions between nutrients and other factors, the distribution of nutrients in different plant species, biochemical functions of nutrient elements, and their contribution to plant growth, yield and product quality. Feasibility and profit are also permanent concerns about plant nutrition in crop management, to which new require ments are now imposed by the need to decrease pollution hazards, a problem of prime importance to preserve the environment of the future. is A deeper insight into basic knowledge further required as well as into practical problems in the domains of agriculture, horticulture, and forestry. Such has been the concern of the International Association for the Optimization of Plant Nutrition (IAOPN) since 1964, promoting International Colloquia every four years as an opportunity for scientists concerned with plant nutrition to report new findings and to exchange ideas, experiences, and techniques. The Eighth International Colloquium for the Optimization of Plant Nutrition was hosted by Portugal and held in Lisbon from 31 August to 8 September 1992, with 280 delegates from 34 countries.