Author
L. T. Kurtz
Bio: L. T. Kurtz is an academic researcher. The author has contributed to research in topics: Soil water & Phosphorus. The author has an hindex of 1, co-authored 1 publications receiving 6078 citations.
Topics: Soil water, Phosphorus
Papers
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TL;DR: Bray and KURTZ as mentioned in this paper verified the total, organically and accessible forMS of phosphorus in soil, and showed that they are available in the US.
Abstract: DETERMINATION OF TOTAL, ORGANIC, AND AVAILABLE FORMS OF PHOSPHORUS IN SOILS ROGER BRAY;L. KURTZ; Soil Science
6,767 citations
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07 Oct 2018
10,515 citations
TL;DR: The Mehlich 3 (M3) extractant as discussed by the authors is composed of 0.2N CH3COOH, 0.25N NH4N03•0.015NNH4F, 0,013NHN03−0.001M EDTA.
Abstract: The objectives of this study were to modify the Mehlich 2 (M2) extractant to include Cu among the extractable nutrients, retain or enhance the wide range of soils for which it is suitable and minimize it's corrosive properties. The substitution of nitrate for chloride anions and the addition of EDTA accomplished those objectives. The new extracting solution, already designated Mehlich 3 (M3) is composed of 0.2N CH3COOH‐0.25N NH4N03‐0.015NNH4F‐0.013NHN03‐0.001M EDTA. Extractions from 105 soils using M3, M2, Bray 1 (Bl) and Ammonium Acetate (AA) were compared to evaluate the new extractant. The quantity of F extracted by M3 exceeded that by M2 20% and that by Bl 4% but the results from all extractions were highly correlated. Extractions of both K and Mg by M3 were 6–8% higher than those by AA and 3–4% higher than those by M2, but, again, there was high correlation among methods. Addition of EDTA increased Cu extractions by 170%, Mn by 50% and Zn by 25%. Cu extractions by M3 correlated with those fr...
4,798 citations
TL;DR: In this paper, a survey of the recent literature shows that the sequential fractionation proposed by Hedley et al. can also be used to separate forms of organically bound soil phosphorus from the geochemically bound fractions.
1,004 citations
TL;DR: The primary mode of interaction of dissolved phosphate with fluvial inorganic suspended particles is via a reversible two-step sorption process as discussed by the authors, which is dependent on the time history of the previous surface sorption and the chemistry of the solid diffusional layer.
Abstract: The primary mode of interaction of dissolved phosphate with fluvial inorganic suspended particles is via a reversible two-step sorption process. The first step, adsorption/desorption on surfaces, has fast kinetics (minutes-hours). The second step, solid-state diffusion of adsorbed phosphate from the surface into the interior of particles, has slow kinetics (days-months) and is dependent on the time history of the previous surface sorption and the chemistry of the solid diffusional layer. Natural clay particles with a surficial armoring of reactive iron and aluminum hydroxyoxides resulting from chemical weathering of rocks and soils have a high capacity for absorbing phosphate in the second step and for maintaining low “equilibrium phosphate concentrations” in solution. Extrapolation of laboratory sorption and extraction experiments with natural soils and suspended sediments to the environment suggests that the phosphate concentrations of unperturbed turbid rivers (SPM > 50 mg liter I) are controlled near the dynamic equilibrium phosphate concentration of their particles (EPC, = 0.2-l .5 PM) and that fluvial suspended particles “at equilibrium” contain up to 10 pmol-P g-l that is desorbable. Release of this phosphate from particles entering the sea produces the characteristic shape and magnitude of input profiles of dissolved phosphate observed in unperturbed estuaries. On a global scale, fluvial particulates could transport from 1.4 to 14 x 1O’O mol yr-I of reactive phosphate to the sea, some 2-5 times more than that in the dissolved load alone.
977 citations
King Juan Carlos University1, University of Vermont2, Pablo de Olavide University3, Technical University of Madrid4, Northern Arizona University5, University of La Serena6, Instituto Potosino de Investigación Científica y Tecnológica7, Universidad Simón Rodríguez8, Ben-Gurion University of the Negev9, State University of Feira de Santana10, Universidad Técnica Particular de Loja11, University of Sfax12, University of New South Wales13, Central University of Venezuela14, National University of San Juan15, University of the Bío Bío16, Virginia Tech College of Natural Resources and Environment17, Ohio State University18, National Agrarian University19, National University of La Pampa20, University of New England (Australia)21, Office of Environment and Heritage22, Spanish National Research Council23, Northeast Normal University24, Agricultural Research Organization, Volcani Center25
TL;DR: A global empirical study relating plant species richness and abiotic factors to multifunctionality in drylands, which collectively cover 41% of Earth’s land surface and support over 38% of the human population, suggests that the preservation of plant biodiversity is crucial to buffer negative effects of climate change and desertification in dryland.
Abstract: Experiments suggest that biodiversity enhances the ability of ecosystems to maintain multiple functions, such as carbon storage, productivity, and the buildup of nutrient pools (multifunctionality). However, the relationship between biodiversity and multifunctionality has never been assessed globally in natural ecosystems. We report here on a global empirical study relating plant species richness and abiotic factors to multifunctionality in drylands, which collectively cover 41% of Earth’s land surface and support over 38% of the human population. Multifunctionality was positively and significantly related to species richness. The best-fitting models accounted for over 55% of the variation in multifunctionality and always included species richness as a predictor variable. Our results suggest that the preservation of plant biodiversity is crucial to buffer negative effects of climate change and desertification in drylands.
941 citations