Effect of compost-, sand-, or gypsum-amended waste foundry sands on turfgrass yield and nutrient content

To prevent the 7 to 11 million metric tons of waste foundry sand (WFS) produced annually in the USA from entering landfi lls, current research is focused on the reuse of WFSs as soil amendments. Th e eff ects of diff erent WFS-containing amendments on turfgrass growth and nutrient content were tested by planting perennial ryegrass (Lolium perenne L.) and tall fescue (Schedonorus phoenix (Scop.) Holub) in diff erent blends containing WFS. Blends of WFS were created with compost or acid-washed sand (AWS) at varying percent by volume with WFS or by amendment with gypsum (9.6 g gypsum kg–1 WFS). Measurements of soil strength, shoot and root dry weight, plant surface coverage, and micronutrients (Al, Fe, Mn, Cu, Zn, B, Na) and macronutrients (N, P, K, S, Ca, Mg) were performed for each blend and compared with pure WFS and with a commercial potting media control. Results showed that strength was not a factor for any of the parameters studied, but the K/Na base saturation ratio of WFS:compost mixes was highly correlated with total shoot dry weight for perennial ryegrass (r = 0.995) and tall fescue (r = 0.94). Th is was further substantiated because total shoot dry weight was also correlated with shoot K/Na concentration of perennial ryegrass (r = 0.99) and tall fescue (r = 0.95). A compost blend containing 40% WFS was determined to be the optimal amendment for the reuse of WFS because it incorporated the greatest possible amount of WFS without major reduction in turfgrass growth

Redox reactions involving chromium, plutonium, and manganese in soils

Plutonium speciation in soils is discussed. Chromium was selected as a model for studying soil Pu. Similarities between Cr and Pu are pointed out, and a hypotheses concerning Pu speciation in soils is presented. Findings from Cr oxidation studies that may be relevant to the problem of Pu oxidation in soils are discussed. (JGB

Development and application of a soil organic matter based soil quality index in mineralized terrane of the Western US

Soil quality indices provide a means of distilling large amounts of data into a single metric that evaluates the soil’s ability to carry out key ecosystem functions. Primarily developed in agroecosytems, then forested ecosystems, we set out to develop and apply an index using the relation between soil organic matter and key soil abiotic and biotic properties in more semi-arid of the Western US arid systems impacted by different geologic mineralization types. We studied these relations in three different mineralization types: serpentine, acid sulfate and Cu/Mo porphyry systems at four different sites in California and Nevada. Soil samples were collected from undisturbed soils in both mineralized and nearby unmineralized terrane as well as waste rock and tailings. We measured eight different microbial parameters (carbon substrate utilization, microbial biomass-C, mineralized-C, mineralized-N and enzyme activities of acid phosphatase, alkaline phosphatase, arylsulfatase, and fluorescein diacetate) along with a number of physicochemical parameters. We developed multiple linear regression models between these parameters and both total organic carbon and total nitrogen, and used the ratio of predicted to measured values as our soil quality index. In most instances, pooling unmineralized and mineralized soil data within a given study site resulted in lower model correlations. Enzyme activity was a consistent explanatory variable in the models across the study sites, while carbon substrate utilization rarely occurred in the models. Though similar indicators were significant in models across different mineralization types, pooling data across sites inhibited model differentiation of undisturbed and disturbed sites. This procedure could be used to monitor recovery of disturbed systems in mineralized terrane and to help link scientific and management disciplines