Search

Student-student interactions are influential parts of field experiences. While competitive judging events are a fun way to engage students in field-based learning, the focus on competition leads to an atmosphere that discourages collaboration between students. The objective of this study was to evaluate the cognitive and affective learning outcomes resulting from intercollegiate collaboration at a soil judging competition. Teams with students from two to three different universities were assigned and referred to as jumble judging teams. Jumble judging was held for the first time in the 2021 Region 5 Collegiate Soil Judging Contest. Learning outcomes were assessed using a pre- and postsurvey, as well as group and individual reflections completed in the field. Student responses were generally positive, with 70% of students expressing agreement or strong agreement that they would like jumble judging to be included in future contests, 54% citing jumble judging as one of the best parts of the contest, and 93% identifying learning outcomes or describing an affective learning experience resulting from jumble judging. Evidence of both cognitive and affective learning were identified through student surveys and reflections. Overall, the event created a collaborative and collegial atmosphere and increased interaction between students from different universities, while maintaining the competitive nature of the event that motivates many students to get involved with judging teams.

Interacting with practitioners and understanding multiple, contradictory, and complex perspectives is an important skill for effectively managing terrestrial resources in the 21st century. Addressing these needs requires innovative approaches in higher education that elevate student learning outcomes and emphasize the affective learning domain through meaningful, place-based interactions with practitioners. We describe an approach taken to expand a traditional soils field course to include emphasis on higher-level student learning outcomes in the affective learning domain. Following the completion of a week-long field study course in which students gain skills in soil description, classification, and interpretation, the expanded second module of the course includes a traveling component in which students experience soils, landscapes, and "lifescapes" (i.e., the lived experiences of practitioners). This second module incorporates practitioners as the primary source of knowledge and is structured to encourage dialogue, understanding, and co-discovery centered around soils and land management. In unstructured narratives, students identified themes in the affective domain--deep collaboration, personal and professional development and sense of place, community, and joy--as transformational experiences in the course that influenced their personal and professional growth and future ability to interact with people from across the geographic, social, and political spectrum.

A survey of introductory soil science or equivalent (ISS[subscript e]) instructors and courses at 79 institutions differing in land-grant status (38 land-grant, 41 non-land-grant) and Carnegie category (48 doctoral, 16 masters, 10 baccalaureate, 2 associate, 3 respondents did not identify by Carnegie classification) was conducted to collect information about the current state of ISS[subscript e] course offerings in the United States. Our data demonstrates little evidence for curricular differences between land-grant and non-land-grant institutions. A "depth" ranking of topical components of these courses showed that soil water concepts and soil classification were allotted the most time, on average. Pedagogical styles were diverse, with 44% of ISS[subscript e] course hours dedicated to active learning, flipped classroom, or online learning formats. There was no significant relationship between class size or institution type and the proportion of the non-lab component of the course taught in alternative formats. Over 40% of respondents expressed interest in connecting with other introductory soils instructors to share course materials and explore new approaches. The results of this survey will serve as a resource to (1) improve general knowledge of the diversity of materials, and methods used to teach introductory soil science courses; (2) assist instructors or institutions in the process of revising or reviewing their introductory soil science courses; and (3) identify opportunities for cross-institutional cooperation or development of course materials and resources.

This study investigated differences in forest structure, organic layer thickness, soil organic carbon, and permafrost depth between late-successional (LS) and postfire (PF; 90-120 years since burn) plots under black spruce (Picea mariana (Mill.) B.S.P.) growing on fine-textured, poorly drained lacustrine sediments in the Copper River Basin, Alaska. Although live stem and seedling density and organic layer thickness were not significantly different between PF and LS plots (28 [+ or -] 7 cm and 31 [+ or -] 10 cm, respectively), we did find a significant difference in soil organic carbon (SOC) stocks (30 [+ or -] 10 kg * [m.sup.-2] and 46 [+ or -] 12 * [m.sup.-2], respectively) permafrost depth (90 [+ or -] 28 cm and 56 [+ or -] 12 cm, respectively). OLT was linearly related to 1 m SOC stocks for LS plots but not for PF plots, and LS plots had a greater proportion of highly decomposed (humic) material in the organic layer. The soil properties of PF plots appear to be on a trajectory of recovery toward those of LS plots with respect to SOC stocks, permafrost depth, and organic layer composition. However, PF plots remain different despite nearly 100 years since fire disturbance and thus they are potentially more sensitive to changes in future fire frequency or climate. Key words: soil carbon, permafrost, black spruce, fire., Resume: Cette etude a examine les differences dans la structure de la foret, l'epaisseur de la couche organique (ECO), le carbone organique du sol (COS) et la profondeur du pergelisol [...]

Deep-sea ferromanganese nodules accumulate trace elements from seawater and underlying sediment porewaters during the growth of concentric mineral layers over millions of years. These trace elements have the potential to record past ocean geochemical conditions. The goal of this study was to determine whether Fe mineral alteration occurs and how the speciation of trace elements responds to alteration over ~3.7Ma of marine ferromanganese nodule (MFN) formation, a timeline constrained by estimates from 9Be/10Be concentrations in the nodule material. We determined Fe-bearing phases and Fe isotope composition in a South Pacific Gyre (SPG) nodule. Specifically, the distribution patterns and speciation of trace element uptake by these Fe phases were investigated. The time interval covered by the growth of our sample of the nodule was derived from 9Be/10Be accelerator mass spectrometry (AMS). The composition and distribution of major and trace elements were mapped at various spatial scales, using micro-X-ray fluorescence (μXRF), electron microprobe analysis (EMPA), and inductively coupled plasma mass spectrometry (ICP-MS). Fe phases were characterized by micro-extended X-ray absorption fine structure (μEXAFS) spectroscopy and micro-X-ray diffraction (μXRD). Speciation of Ti and V, associated with Fe, was measured using micro-X-ray absorption near edge structure (μXANES) spectroscopy. Iron isotope composition (δ56/54Fe) in subsamples of 1-3mm increments along the radius of the nodule was determined with multiple-collector ICP-MS (MC-ICP-MS). The SPG nodule formed through primarily hydrogeneous inputs at a rate of 4.0±0.4mm/Ma. The nodule exhibited a high diversity of Fe mineral phases: feroxyhite (δ-FeOOH), goethite (α-FeOOH), lepidocrocite (γ-FeOOH), and poorly ordered ferrihydrite-like phases. These findings provide evidence that Fe oxyhydroxides within the nodule undergo alteration to more stable phases over millions of years. Trace Ti and V were spatially correlated with Fe and found to be adsorbed to Fe-bearing minerals. Ti/Fe and V/Fe ratios, and Ti and V speciation, did not vary along the nodule radius. The δ56/54Fe values, when averaged over sample increments representing 0.25-0.75Ma, were homogeneous within uncertainty along the nodule radius, at -0.12±0.07‰ (2sd, n=10). Our results indicate that the Fe isotope composition of the nodule remained constant during nodule growth and that mineral alteration did not affect the primary Fe isotope composition of the nodule. Furthermore, the average δ56/54Fe value of -0.12‰ we find is consistent with Fe sourced from continental eolian particles (dust). Despite mineral alteration, the trace element partitioning of Ti and V, and Fe isotope composition, do not appear to change within the sensitivity of our measurements. These findings suggest that Fe oxyhydroxides within hydrogenetic ferromanganese nodules are out of geochemical contact with seawater once they are covered by subsequent concentric mineral layers. Even though Fe-bearing minerals are altered, trace element ratios, speciation and Fe isotope composition are preserved within the nodule.

A major challenge to implementing effective soil health assessments is how to distinguish the effects of management from underlying soil variability driven by inherent soil properties. This challenge has important consequences for the use of soil health indicators as tools for monitoring and assessment because soil‐forming factors constrain the range of indicator values and the magnitude of management‐induced changes. Here, we present results from a statewide survey of 15 soil health indicators measured on 30 fields on commercial farms across four major land resource areas in Minnesota. Fields included in the study differed in tillage, cover crop implementation, and crop rotation. Within each field, we collected samples from upper and lower hillslope positions to quantify the effect of topography. We consistently detected differences in soil health indicators between regions (13/15 indicators) and hillslope positions (8/15 indicators). However, only wet aggregate stability was sensitive to management across regions and years, highlighting the importance of physical indicators of soil health. This result was surprising in light of existing literature supporting the sensitivity of many soil health indicators to management, but it is consistent with other studies conducted in high organic matter soils in the Upper US Midwest. Our results highlight the need for regionally representative datasets to guide the development of interpretations and benchmarks for soil health indicators. This is particularly important when soil health indicators are applied outside traditional research contexts (such as in commercial soil health testing), where interpretation must take place without the benefit of historical baseline data. [ABSTRACT FROM AUTHOR]