N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar d 15 N may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root d 15 N and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar d 15 N than the regional driver of N deposition. Foliar d 15 N increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar d 15 N was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root d 15 N was more tightly coupled to forest floor properties than was foliar d 15 N. We observed a pattern of decreasing foliar d 15 N values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar d 15 N included species composition and climate. Relationships between foliar d 15 N and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar d 15 N, due to the importance of ammonium deposition in this region. Our results suggest that examining d 15 N values of foliage may improve understanding of how forests respond to the cascading effects of N deposition.

Use of metal-rich sewage sludge as soil fertilizer may result in trace- metal contamination of soils. This study was conducted to evaluate the effects of long-term sludge application on trace-metal (Zn, Cu, Pb, and Ni) distribution and potential bioavailability in Nigerian soils under a tropical wet-dry climate. Total metal analyses, sequential chemical fractionation, and DTPA extractions were carried out on samples of control and sludge-amended pedons in Nigeria (a Rhodic Kandiustult and two Rhodic Kandiustalfs from Nigeria, respectively). The sewage sludge applied to the soils contained higher levels of Zn and Cu than Pb and Ni. The control pedon contained low levels of all four metals. Soil enrichment factors (EF) were calculated for each metal in the sludge-amended pedons. Compared with the control soil, the sludge-amended pedons showed elevated levels of Zn and Cu, reflecting the trace-metal composition of the sewage sludge. Zinc and Cu in the sludge-amended soils were strongly enriched at all depths in the profile, indicating that they had moved below the zone of sludge application. The sequential extraction and DTPA analyses indicated that the sludge-amended soils contained more readily extractable and bioavailable metal ions than the unamended soil.

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Core Ideas Enrollment increased in most soil science courses from 2009 to 2013. Students from many different majors took soil science coursework. Total female enrollment increased, but the percentage of female students decreased. Soil judging participation remained consistent. Student to faculty ratio went up between 2009 and 2013. Data were collected from 10 universities in the United States on declared academic majors and gender of students enrolled in seven different soil science courses over a 5‐yr period. Combined trends for all courses and trends for each individual course were evaluated. Data were also collected on the number of students participating in soil judging as well as tenure track and non‐tenure track full time equivalent (FTE) soil science faculty positions. Environmental science, crop science/horticulture/agronomy, and other agricultural students enrolled in soil science courses in the greatest numbers. Environmental science and engineering students showed rapid increases in enrollment, while crop science/horticulture/agronomy and soil science student enrollment declined. Soil physics was the only class where declared soil science students were the single largest enrolled group. Soil judging numbers were consistent, while FTE faculty showed a slight decline. Students from many different academic majors took soil science courses at the universities investigated, and the most common majors in these courses depended on the course and the material it addressed. Overall student enrollment increased in all subject areas investigated except soil physics. While the results from this study are somewhat mixed, the overall growth in student enrollment in soil science courses at the investigated universities, as well as the broad range of majors enrolled in soil science coursework, indicate an upward trajectory in soil science education at these universities.

Forest management practices such as prescribed burning and thinning are commonly used to restore degraded forest communities in the Southern Appalachians. Prescribed treatments influence physical and chemical properties of soils and change the balance of nutrients such as carbon and nitrogen. This study was conducted to investigate the initial impacts of prescribed burning, thinning and a combination of prescribed thinning and burning on total carbon and nitrogen pools, as well as other properties, in soil and forest floor. Effects of these disturbance regimes were tested on Typic Hapludults at the Bankhead National Forest in Northern Alabama. Results show that prescribed burning alone led to significant increases in total C and N contents in soil surface horizons. Burning alone also resulted in changes in exchangeable Na pools and significant increases in pH values throughout the study sites. Combination of prescribed thinning and burning did not result in significant changes in total C and N concentrations. However, significant increases in K and Na concentrations were observed in these sites. Prescribed thinning alone did not appear to impact total C and total N concentrations, soil acidity or exchangeable Ca and Mg concentrations, but caused significant increases in Na and decreases in K concentrations. Results of the study indicated that prescribed burning alone appeared to have a stronger impact on total C and N pools than a combination of prescribed thinning and burning. Use of prescribed thinning alone did not have any effect on total C and N pools in soils and forest floor. While prescribed burning alone and a combination of thinning and burning led to changes in exchangeable K and Na pools, no change was detected in either Ca or Mg concentrations.