Early Soil Physics into the Mid-20th Century

Gardner, Wayne A.

doi:10.1007/978-1-4613-8612-4_1

Cited by 17 publications

(5 citation statements)

References 326 publications

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“…Soil tests conducted by the Penn State Agricultural Analytical Services Laboratory included P, K, Mg, Ca, S, Zn, Cu, CEC, CEC-K%, CEC-CA%, CEC-Mg% and soil organic matter by loss-on-ignition (LOI). Additional tests were pH and electrical conductivity (1:2 soil:water slurries), particle size analysis by the pipet method 71 , gravimetric water content 72 , matric potential 73 , and POXC 74 . Soil organic matter determined by LOI reflects both labile and recalcitrant organic matter in the soil, whereas permanganate oxidizable carbon reflects the labile pool that supports biological activity more readily 75 .…”

Section: Soil Chemical and Physical Measurements And Analyses Data Fmentioning

confidence: 99%

Fungal community shifts in soils with varied cover crop treatments and edaphic properties

Cloutier

Murrell

Barbercheck

et al. 2020

Sci Rep

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Cover cropping is proposed to enhance soil microbial diversity and activity, with cover crop type affecting microbial groups in different ways. We compared fungal community compositions of bulk soils differing by cover crop treatment, season, and edaphic properties in the third year of an organic, conventionally tilled rotation of corn-soybean-wheat planted with winter cover crops. We used Illumina amplicon sequencing fungal assemblages to evaluate effects of nine treatments, each replicated four times, consisting of six single winter cover crop species, a three-species mixture, a six-species mixture, and fallow. Alpha-diversity of fungal communities was not affected by cover crop species identity, function, or diversity. Sampling season influenced community composition as well as genus-level abundances of arbuscular mycorrhizal (AM) fungi. Cover crop mixtures, specifically the three-species mixture, had distinct AM fungal community compositions, while cereal rye and forage radish monocultures had unique Core OTU compositions. Soil texture, pH, permanganate oxidizable carbon, and chemical properties including Cu, and P were important variables in models of fungal OTU distributions across groupings. These results showed how fungal composition and potential functions were shaped by cover crop treatment as well as soil heterogeneity.Microbial diversity is an important aspect of soil health, as soil microbial communities mediate many biogeochemical processes and are sensitive to disturbances that can lead to long-lasting ecosystem effects 1 . Greater richness and evenness in the representation of bacteria and fungi in soils can help mitigate plant responses to environmental stressors 2 . With the advent of high-throughput DNA sequencing technologies that allow for more detailed genetic information, we can determine if and how microbial compositions shift in response to disturbance and edaphic differences and, to some degree, what those changes may mean for ecosystem processes.Cover cropping is the practice of growing ground-covering crops during the intervals between successive cash crops. Cover cropping imparts numerous benefits to soil, including the addition of organic carbon (C) from roots, root exudates, and aboveground residues and the improvement of soil structure and tilth 3-5 . Ecosystem services provided by cover crops include protection from soil erosion, enhanced soil water-holding capacity, reduced weed colonization and growth, plant resilience to pathogens and increased crop yield 5,6 . Legume cover crops provide biologically fixed nitrogen (N), while grasses take up excess soil inorganic N and improve N retention. A complete suite of ecosystem services is not deliverable by any one cover crop species. Thus, planting mixtures of cover crops has been proposed as a means to provide varied combinations of ecosystem services based on the functional traits of individual cover crop species 5,7-10 .Cover crops may alter microbial community diversity and function by varying the types and composition of exuded C...

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Section: Soil Chemical and Physical Measurements And Analyses Data Fmentioning

confidence: 99%

Fungal community shifts in soils with varied cover crop treatments and edaphic properties

Cloutier

Murrell

Barbercheck

et al. 2020

Sci Rep

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“…In the early stages of soil physics, methods have been developed for determining the WRC or the saturated conductivity (Gardner, 1986). Determination of the water retention characteristic can be done directly, by pairing water content and water potential measurements in the laboratory or in the field.…”

Section: Classification Of Methodsmentioning

confidence: 99%

Determining Soil Hydraulic Properties

Durner

Lipsius

2005

Encyclopedia of Hydrological Sciences

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Hydraulic properties are required for modeling water and solute transport in unsaturated soils. The bottleneck for the successful application of numerical simulation models lays usually in their parameter estimation requirements. Methods to determine hydraulic properties can be classified into indirect and direct approaches. Indirect methods encompass the estimation of hydraulic properties by pedotransfer functions from more easily measured soil properties, and the prediction of the unsaturated hydraulic conductivity function from the water retention curve ( WRC ). In direct methods, observations of flow attributes from laboratory or field experiments are evaluated. This article reviews common methods to estimate the hydraulic conductivity function from the water retention characteristic and various direct measurement techniques in the laboratory and the field. We conclude with an outlook on contemporary developments in measurement techniques, stressing the key role of inverse modeling of experiments to derive optimum hydraulic properties and the importance of a future combination of noninvasive measurement techniques with inverse modeling by stochastic data fusion.

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“…At the turn of the 20th century, Milton Whitney, who believed that soil physical properties affected crop productivity more profoundly than soil fertility (Nimmo & Landa, 2005), was appointed head of the U.S. Department of Agriculture (USDA) Division of Soils, and later the Bureau of Soils (BOS) (Gardner, 1986). Under the lead of Whitney, Lyman Briggs investigated the ability of soil to retain water through experiments with vertical soil columns predicated on the basis of interactions between capillarity and gravitational forces (Briggs, 1897; Landa & Nimmo, 2003).…”

Section: Energy Concept Of Soil Watermentioning

confidence: 99%

Soil water potential: A historical perspective and recent breakthroughs

Luo

Zhang

et al. 2022

Vadose Zone Journal

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Soil water potential is a cornerstone in defining the thermodynamic state of soil water required to quantify phenomena such as water phase change, water movement, heat transfer, electric current, chemical transport, and mechanical stress and deformation in the earth's shallow subsurface environment. This potential has historically been conceptualized as free energy stored in a until volume of soil water. Though the concept of soil water potential has been evolving over the past 120 yr, a consensual definition is still lacking, and answers to some fundamental questions remain controversial and elusive. What are the origins and mechanisms for the free energy of soil water? Can the common mathematical expression of soil water potential as superposition of gravitational, osmotic, and matric potentials be used to define water phase transitions in soil? Are these major components of soil water potential independent or coupled? Is pore water pressure always tensile under unsaturated conditions? If so, how can soil water density be as high as 1.7 g cm −3 ? How do adsorptive soilwater interactions originating from the electromagnetic field around and within soil particles transfer to mechanical pore pressure? In this review, the authors (a) provide critical analysis of historical definitions of soil water potential to identify their strengths, limitations, and flaws; (b) synthesize the origins of electromagnetic energies in soil to clarify the fundamental differences between adsorptive and capillary soil water potential mechanisms; (c) introduce a recently emerging concept of soil matric potential that unifies contributions of adsorption and capillarity to soil water potential; and (d) illustrate the generality and promise of the unified definition of soil water potential for answering some of the fundamental questions that remain elusive to the hydrology, geoengineering, and geoscience communities.

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Early Soil Physics into the Mid-20th Century

Cited by 17 publications

References 326 publications

Fungal community shifts in soils with varied cover crop treatments and edaphic properties

Fungal community shifts in soils with varied cover crop treatments and edaphic properties

Determining Soil Hydraulic Properties

Soil water potential: A historical perspective and recent breakthroughs

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