<p> The quantification and prediction of soil properties is fundamental to further understanding the Critical Zone (CZ). In this study we aim to quantify and predict soil properties within a forested catchment, Marshall Gulch, AZ. Input layers of soil depth (modeled), slope, Saga wetness index, remotely sensed normalized difference vegetation index (NDVI) and national agriculture imagery program (NAIP) bands 3/2 were determined to account for 95% of landscape variance and used as model predictors. Target variables including soil depth (cm), carbon (kg/m²), clay (%), Na flux (kg/m²), pH, and strain are predicted using multivariate linear step-wise regression models. Our results show strong correlations of soil properties with the drainage systems in the MG catchment. We observe deeper soils, higher clay content, higher carbon content, and more Na loss within the drainages of the catchment in contrast to the adjacent slopes and ridgelines.</p>

<p> Carbon isotope studies are commonly used to provide a proxy for past vegetation communities and for evaluating environmental change. Original studies suggested carbon isotope ratios of soil organic matter (SOM) faithfully preserved the isotopic composition of standing vegetation with little or no modification in the pedogenic and shallow burial environment. Recent studies of modern soils and laboratory experiments suggest that this may not necessarily be the case and that degradation of SOM in the burial environment may alter the original C-isotope ratio of bulk SOM. A first step in addressing the issue is to begin to understand the transformations of SOM in the burial environment; of particular interest in this study are transformations involving microbial residues. Sedimentary sequences with stacked buried soils afford the opportunity to study the changes that may occur through time and are especially useful if numerical ages and other environmental proxies are present.</p><p> The objective of this study is to thoroughly investigate the composition and quantity of organic matter that has been preserved in the surface and buried soils at the Claussen site, using Fourier Transform Infrared Spectroscopy (FTIR), which provides an estimate for the abundance of organic matter components preserved in each paleosol's SOM. We can trace the fate of bioavailable OM and determine the magnitude of preferential decay of SOM with time by first comparing the composition of bulk SOM to the composition of physically protected carbon, located in soil microaggregates (Christensen, 1992) of the stacked buried soils. The results of this project suggest differences in the composition of paleosol and surface soil SOM that could impact paleovegetation interpretations derived from &delta;¹³C values.</p>

<p> We investigated the agricultural use of locally produced biosolids compost, the fate of the antibiotic ciprofloxacin during the composting process, community perceptions about biosolids, and sociological factors of community involvement in waste management research and decision-making. </p><p> Two biological assays were used to determine if the antibiotic ciprofloxacin selects for and amplifies ciprofloxacin-resistant bacteria during composting. A third biological assay measured the capacity of compost to adsorb ciprofloxacin from solution. Our results show that the ciprofloxacin had no selective effect on resistant populations of bacteria during composting and that the compost was capable of adsorbing and effectively neutralizing this antibiotic. </p><p> A two-year field trial was conducted to evaluate the potential of biosolids compost as a high-carbon soil amendment in local agriculture. Potatoes and small grains were grown with biosolids compost and/or synthetic fertilizer and effects on crop yield, soil fertility, and soil quality were measured. Biosolids compost increased potato tuber and grain yield in the second year, demonstrating cumulative effects of repeated compost applications. In this study, the value of biosolids compost was primarily as a source of nitrogen, plant available phosphorus, and soil organic matter. </p><p> A mail survey of 1,374 Skagit County households was conducted to gain insight into community perceptions about the use of biosolids in local agriculture, interest in using biosolids compost as a soil amendment, and desire to participate in local waste management decision-making processes. Mail survey results and participant observation were used to develop a case study of community involvement in waste management research and decision-making in the town of La Conner. </p><p> This project addressed challenges inherent in conducting research on a controversial topic while developing a new collaborative research model for the region. Scientists, public planners and biosolids managers may be able to build and improve upon what was learned here in their efforts to develop effective regional waste management solutions.</p>

<p> ¹⁰Be_met, or cosmogenic beryllium, has a long half-life of 1.4 million years and quick adsorption on soil particles, which may make it ideal for dating soil erosion in historical context. However, there are questions on about the fundamental assumptions of the retentivity of ¹⁰Be_met. This manuscript explores these assumptions and the context of nutrient cycling in a natural forest setting. </p><p> To see if ¹⁰Be_met was being cycled through the trees, and at what rate, we looked at the[¹⁰Be_met] in the soil, 4 species of trees, and their leaves. The isotopic ratio¹⁰Be/⁹Be in all four tree species was comparable to the soil on which they grow, ranging from 6-8 x 10 ^-9. However, there was one exception with hickory (<i>Carya spp.</i>) which strongly bioaccumulate beryllium with an average of 0.38 ppm dry weight in the wood. Abscised hickory leaves have a higher [Be] of 2.0 ppm, over 10 times higher than in the soil. </p><p> Using standard allometric equations relating tree biomass to trunk diameter, and assuming that belowground biomass has the same [Be] as aboveground, we calculate that hickory trees at our site contain approximately 1% of the total ¹⁰Be_met under their canopy and that ~10% of this Be is cycled annually by leaf abscission. It is not clear at this point what fraction of litterfall Be is recycled into the plant, returned to the soil, or carried to groundwater as organic chelates. </p><p> Hickory trees occupy an average of ~10% of the oak-hickory forest area. Assuming that trees are randomly distributed, that litterfall Be is returned to the soil, and maintaining a constant ¹⁰Be_met budget over time for simplicity, then more than half of all ¹⁰Be_met in the forest soil will have passed through a hickory tree over the past 10 ky. Fully 90% of all ¹⁰Be_met will pass through a hickory tree over a period of ~25 ky. It is clear that hickory trees can transport a sizable fraction of the total ¹⁰Be_met in their nutrient cycle, and that they may be responsible for landscape-scale Be mobility.</p>

Thesis (Ph.D.)--University of California, Davis, 2005. / (UnM)AAI3191201. Source: Dissertation Abstracts International, Volume: 66-10, Section: A, page: 3746. Adviser: Richard Howitt.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7212. Adviser: Tim R. Ellsworth. Includes bibliographical references (leaves 152-162) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph. D.)--Syracuse University, 2003. / "Publication number AAT 3113254."

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3662. Adviser: Praveen Kumar. Includes bibliographical references (leaves 133-139) Available on microfilm from Pro Quest Information and Learning.

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