451 research outputs found

    Micro-X-Ray Fluorescence, Micro-X-Ray Absorption Spectroscopy, and Micro-X-Ray Diffraction Investigation of Lead Speciation after the Addition of Different Phosphorus Amendments to a Smelter-Contaminated Soil

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    Citation: Baker, Lucas R., Gary M. Pierzynski, Ganga M. Hettiarachchi, Kirk G. Scheckel, and Matthew Newville. “Micro-X-Ray Fluorescence, Micro-X-Ray Absorption Spectroscopy, and Micro-X-Ray Diffraction Investigation of Lead Speciation after the Addition of Different Phosphorus Amendments to a Smelter-Contaminated Soil.” Journal of Environmental Quality 43, no. 2 (2014): 488–97. https://doi.org/10.2134/jeq2013.07.0281.The stabilization of Pb on additions of P to contaminated soils and mine spoil materials has been well documented. It is clear from the literature that different P sources result in different efficacies of Pb stabilization in the same contaminated material. We hypothesized that the differences in the efficacy of Pb stabilization in contaminated soils on fluid or granular P amendment addition is due to different P reaction processes in and around fertilizer granules and fluid droplets. We used a combination of several synchrotron-based techniques (i.e., spatially resolved micro-X-ray fluorescence, micro-X-ray absorption near-edge structure spectroscopy, and micro-X-ray diffraction) to speciate Pb at two incubation times in a smelter-contaminated soil on addition of several fluid and granular P amendments. The results indicated that the Pb phosphate mineral plumbogummite was an intermediate phase of pyromorphite formation. Additionally, all fluid and granular P sources were able to induce Pb phosphate formation, but fluid phosphoric acid (PA) was the most effective with time and distance from the treatment. Granular phosphate rock and triple super phosphate (TSP) amendments reacted to generate Pb phosphate minerals, with TSP being more effective at greater distances from the point of application. As a result, PA and TSP were the most effective P amendments at inducing Pb phosphate formation, but caution needs to be exercised when adding large amounts of soluble P to the environment

    Speciation of phosphorus in a fertilized, reduced-till soil system: in-field treatment incubation study

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    Citation: Khatiwada, Raju, Ganga M. Hettiarachchi, David B. Mengel, and Mingwei Fei. “Speciation of Phosphorus in a Fertilized, Reduced-Till Soil System: In-Field Treatment Incubation Study.” Soil Science Society of America Journal 76, no. 6 (2012): 2006–18. https://doi.org/10.2136/sssaj2011.0299.Phosphorus management in reduced-tillage systems is a great concern for farmers. Conclusive positive results of deep-banding P fertilizers compared with broadcast application and the chemistry of reduced-tillage systems remain unclear. Knowledge of the dominant solid P species present in soil following application of P fertilizers and the resulting potential P availability would help us understand and efficiently manage P in reduced-tillage systems. The objective of this research was to study the influence of placement (broadcast vs. deep-band P), fertilizer source (granular vs. liquid P), and time on the reaction products of P under field conditions. Changes in soil pH, resin-extractable P, total P, and speciation of P were determined at different distances from the point of fertilizer application at 5 wk and 6 mo after P application at a rate of 75 kg ha−1 to a soil system that was under long-term reduced tillage. Resin-extractable P was lower for broadcast treatments compared with deep-band treatments for both time periods. Resin-extractable P was greater in the liquid P-treated soils than in the granular P-treated soils. Speciation results showed that granular P fertilizers tended to form Fe–P-like forms, whereas liquid forms remained in adsorbed P-like forms in the soil 5 wk after application; moreover, speciation results showed granular P fertilizers precipitated less when deep-banded. During the 6-mo period following application, reaction products of broadcast granular, broadcast liquid, and deep-band granular fertilizers transformed to Ca-phosphate or mixtures of Ca-, Fe- and adsorbed-phosphate-like forms, whereas deep-band liquid P remained as mainly adsorbed P-like forms. Deep-banding of P would most likely provide a solution that is both agronomically and environmentally efficient for reduced-till farmers

    Why the Russia-Ukraine war isn't just about NATO and Putin

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    Most explanations of Russia’s invasion of Ukraine focus on NATO expansion or Vladimir Putin’s personal ambitions. Yet as Gabriel A. Pierzynski and Jonathan Joseph argue, such accounts miss that Russia’s imperial state structure shapes the state’s behaviour regardless of who leads it or how the West reacts

    Patrimonial imperialism: a taxonomy of the causes of the Russo‐Ukrainian war

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    Explanations of the causes of the Russo‐Ukrainian war tend to drift towards one of two lines of argument. These are the ‘NATO expansion’ argument, chiefly focusing on the structure of the international system and the possibility of the acceptance of Ukraine into NATO, and the ‘Putin's war’ argument, which attempts to place the bulk of blame for the war on the actions and agency of Putin himself. Both arguments might better be considered as focused on processes rather than structures, and this leads to explanations operating at the level of actual manifestation of causes rather than real and underlying structures. Critical realism cannot tell us what structures are the right ones to study, but a plausible explanation might lie in the notion of the patrimonial imperialism of Russian state–society relations. To address the issue of an alternative to these arguments, one overly structural and the other overly agential, this article proposes a framework referred to as patrimonial imperialism. It will attempt to show how an imperialist state structure can come to perpetuate and ingrain itself and thereby induce actors to behave in certain ways consistent with the state structure. The above framework will be integrated into a model of stratified reality and will situate the constituent arguments surrounding the causes of the war into an ontological framework that will allow greater clarity and coherence of thought when attempting to grapple with the causes of the Russo‐Ukrainian war

    Surface Runoff Characteristics from Claypan Soil in Southeastern Kansas Receiving Different Plant Nutrient Sources and Tillage

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    Preliminary results show that two-year average total nitrogen (N) runoff losses and ortho-phosphorus (P) and total P runoff losses in the second year were greater with N-based turkey litter/no-till applications than P-based turkey litter or fertilizer-only applications. Incorporation of turkey litter applied based on N requirements resulted in N and P losses that did not differ from losses from P-based or fertilizer-only treatments. Chemical and statistical analyses of third-year samples will allow for final results and interpretation

    Response of Soybean Grown on a Claypan Soil in Southeastern Kansas to the Residual of Different Plant Nutrient Sources and Tillage

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    The residual from previous high rate turkey litter applications, which were based on N requirements of the previous grain sorghum crop, increased soybean yield above that obtained from the residual of P-based turkey litter applications (low rate), commercial fertilizer, or the control. Even though early soybean growth was not significantly affected by residual treatments, the greatest dry matter production at the R6 growth stage was where the N-based litter had been applied and incorporated

    Response of Soybean Grown on a Claypan Soil in Southeastern Kansas to the Residual of Different Plant Nutrient Sources and Tillage

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    The residual effects of turkey litter and fertilizer amendments applied in previous years had little effect on the yield, yield components, and dry matter production of the following soybean crop grown in 2014

    Response of Soybean Grown on a Claypan Soil in Southeastern Kansas to the Residual of Different Plant Nutrient Sources and Tillage

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    The residual from previous high rate turkey litter applications, which were based on N requirements of the previous grain sorghum crop, increased soybean yield above that obtained from the residual of P-based turkey litter applications (low rate), commercial fertilizer, or the control. Even though early soybean growth was not significantly affected by residual treatments, the greatest dry matter production at the R6 growth stage was where the N-based litter had been applied and incorporated
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