Soil health: A common focus for one health and planetary health interventions.

Proponents of both the One Health and Planetary Health paradigms have acknowledged that current methods of agricultural food production are driving many environmental changes with negative human health consequences, including climate change, deforestation, and the emergence of zoonotic disease and antimicrobial resistance. Currently, the training of human health, veterinary, and public health professionals typically does not include aspects of soil health. Much of the resultant discussion in One Health and Planetary Health circles regarding interventions to address the health impact of agricultural practices has focused on measures such as advocating for dietary change toward plant based diets and increasing food safety, biosecurity, disease surveillance and antimicrobial stewardship. A greater understanding of soil health and its relationship to agricultural practices could prove foundational to many of the problems that the One Health and Planetary Health perspectives aim to address, including antimicrobial resistance, zoonotic disease emergence, food security, and climate change. A consequent global focus on the health of soils offers a promise of specific opportunities for preventive interventions and a greater convergence between the One Health and Planetary Health approaches.

Trends in soil organic matter and topsoil thickness under regenerative practices at the University of Washington student farm.

Conventional methods of agriculture, especially tillage, are often accompanied by soil degradation in the form of erosion and organic matter depletion. Regenerative agricultural methods seek to repair soil ecosystems by building topsoil and soil organic matter (SOM), decreasing reliance on chemical fertilizers and increasing both water retention capacity and the diversity and quantity of soil microbial and fungal communities. The University of Washington (UW) student farm is an organic and regeneratively managed site on the UW Seattle campus. Over the past 20 years the farm gradually expanded so locations on the farm encompass both unimproved topsoil and soils managed regeneratively for periods of 5 to 20 years. This arrangement allows a time-trend analysis of soil development under regenerative methods. Measurements of topsoil thickness (defined as the distance from the ground surface to the base of the soil A horizon) and organic matter content were collected across 14 distinct plots on the farm to quantify trends over time and estimate net change in SOM (and soil organic carbon, or SOC). While SOM content weakly increased by 0.5% per year, topsoil thickness exhibited a significant linear increase of 0.86 cm per year. Over a twenty-year period under the management practices of the UW Farm total organic carbon storage in soils, determined using topsoil thickness, density, and SOC content, increased by between 4 and 14 t ha-1 yr-1. The general increases in topsoil thickness, SOM content, and total soil carbon demonstrate the potential of soil-health-focused practices to help maintain a productive and efficient urban growing space.

Soil health and nutrient density: preliminary comparison of regenerative and conventional farming.

Several independent comparisons indicate regenerative farming practices enhance the nutritional profiles of crops and livestock. Measurements from paired farms across the United States indicate differences in soil health and crop nutrient density between fields worked with conventional (synthetically-fertilized and herbicide-treated) or regenerative practices for 5 to 10 years. Specifically, regenerative farms that combined no-till, cover crops, and diverse rotations-a system known as Conservation Agriculture-produced crops with higher soil organic matter levels, soil health scores, and levels of certain vitamins, minerals, and phytochemicals. In addition, crops from two regenerative no-till vegetable farms, one in California and the other in Connecticut, had higher levels of phytochemicals than values reported previously from New York supermarkets. Moreover, a comparison of wheat from adjacent regenerative and conventional no-till fields in northern Oregon found a higher density of mineral micronutrients in the regenerative crop. Finally, a comparison of the unsaturated fatty acid profile of beef and pork raised on one of the regenerative farms to a regional health-promoting brand and conventional meat from local supermarkets, found higher levels of omega-3 fats and a more health-beneficial ratio of omega-6 to omega-3 fats. Despite small sample sizes, all three crop comparisons show differences in micronutrient and phytochemical concentrations that suggest soil health is an under appreciated influence on nutrient density, particularly for phytochemicals not conventionally considered nutrients but nonetheless relevant to chronic disease prevention. Likewise, regenerative grazing practices produced meat with a better fatty acid profile than conventional and regional health-promoting brands. Together these comparisons offer preliminary support for the conclusion that regenerative soil-building farming practices can enhance the nutritional profile of conventionally grown plant and animal foods.

Evidence for repeated failure of the giant Yigong landslide on the edge of the Tibetan Plateau.

Field surveys and radiocarbon dating of detrital materials provide evidence that repeated landslides dammed the Yigong Tsangpo River ca. 3500 BC, 1300 BC, 1000 BC, 600 BC, and twice more recently. Together with historical slides in 1900 and 2000, these six older slides make for a total of eight known channel-damming landslide events at the same location over the past six millennia, indicating sub-millennia recurrence intervals over this time period. Together with the likely incomplete nature of the sedimentary record of past channel-damming episodes uncovered to date, our findings indicate late Holocene multi-century-scale recurrence intervals for large landslides at this location. Hence, the riverbed at and immediately upstream of this location may have been inundated by sediment, and therefore not incising, for much of the post-glacial period. Together with the location of this landslide complex at the head of the major knickzone defining the fluvial edge of the Tibetan Plateau, our findings support the hypothesis that repeated glacial and landslide damming in this region inhibited headward propagation of river incision into the Tibetan Plateau.

Extra Nodal Rosai-Dorfman Disease Originating in the Nasal and Paranasal Complex and Gnathic Bones: A Systematic Analysis of Seven Cases and Review of Literature.

Rosai-Dorfman disease (RDD) is a benign, self-limiting histiocytosis of unknown etiology. The classic form of the condition includes a painless cervical lymphaenopathy accompanied by fever, weight loss and an elevated ESR. Extra nodal RDD (ENRDD) is most frequent in the head and neck. Thirty-eight cases of ENRDD have been described. Seven cases of ENRDD were identified in our pathology biopsy services. The demographic and clinical information was tabulated logically on the basis of age, gender, location and presence or absence of symptoms, treatment and follow-up. Radiographic and histopathological features were also examined. The findings in these cases were correlated with those available from the previously reported cases. Six cases affected women and one case was diagnosed in a male. The age ranged from 22-55 years. Three cases presented as a nasal mass. One of these lesions extended into the paranasal sinuses. One case was located in the maxilla and extended to involve the maxillary sinus. Three cases were diagnosed in the mandible. The maxillary and one mandibular lesion (Case 2) resulted in significant painful irregular bone destruction with a non-healing socket and tooth mobility respectively. One mandibular lesion was asymptomatic (Case 6). The third case affecting the mandible presented as a rapidly expansile mass following a tooth extraction (Case 7). Nasal masses presented with symptoms of obstruction. Nasal masses were excised with no recurrence from up to 2-3 years of follow-up. The mandibular lesions were curetted aggressively. The oral mass in Case 7 was excised synchronously. No recurrence up to 2 years was recorded in Case 2. Follow-up information is not available for Cases 6 and 7. The maxillary lesion was not intervened surgically. The patient has persistent but stable disease for a follow-up period of 2 years. ENRDD is rarely considered in the differential diagnosis in the absence of lymph node involvement. Lesions of ENRDD resemble many other histiocytic and histiocyte-rich lesions of the head and neck. This makes the diagnosis of ENRDD challenging with the potential for under diagnosis or misdiagnosis and delay in treatment.

Anthropogenic strath terrace formation caused by reduced sediment retention.

Across North America, human activities have been shown to cause river incision into unconsolidated alluvium. Human-caused erosion through bedrock, however, has only been observed in local and isolated outcrops. Here, we test whether splash-dam logging, which decreased in-stream alluvial cover by removing much of the alluvium-trapping wood, caused basin-wide bedrock river incision in a forested mountain catchment in Washington State. We date incision of the youngest of four strath terraces, using dendrochronology and radiocarbon, to between 1893 CE and 1937 CE in the Middle Fork Teanaway River and 1900 CE and 1970 CE in the West Fork Teanaway River, coincident with timber harvesting and splash damming in the basins. Other potential drivers of river incision lack a recognized mechanism to cause T1 incision or are not synchronous with T1 incision. Hence, the close temporal correspondence suggests that reduced sediment retention triggered by splash damming led to the observed 1.1 mm⋅y-1 to 23 mm⋅y-1 of bedrock river incision and reduction of the active floodplain to 20% and 53% of its preincision extent on the Middle and West Forks, respectively. The development of such anthropogenic bedrock terraces may be an emerging, globally widespread physiographic signature of the Anthropocene.

Tectonic control on the persistence of glacially sculpted topography.

One of the most fundamental insights for understanding how landscapes evolve is based on determining the extent to which topography was shaped by glaciers or by rivers. More than 10(4) years after the last major glaciation the topography of mountain ranges worldwide remains dominated by characteristic glacial landforms such as U-shaped valleys, but an understanding of the persistence of such landforms is lacking. Here we use digital topographic data to analyse valley shapes at sites worldwide to demonstrate that the persistence of U-shaped valleys is controlled by the erosional response to tectonic forcing. Our findings indicate that glacial topography in Earth's most rapidly uplifting mountain ranges is rapidly replaced by fluvial topography and hence valley forms do not reflect the cumulative action of multiple glacial periods, implying that the classic physiographic signature of glaciated landscapes is best expressed in, and indeed limited by, the extent of relatively low-uplift terrain.

Glaciated valleys in Europe and western Asia.

In recent years, remote sensing, morphometric analysis, and other computational concepts and tools have invigorated the field of geomorphological mapping. Automated interpretation of digital terrain data based on impartial rules holds substantial promise for large dataset processing and objective landscape classification. However, the geomorphological realm presents tremendous complexity and challenges in the translation of qualitative descriptions into geomorphometric semantics. Here, the simple, conventional distinction of V-shaped fluvial and U-shaped glacial valleys was analyzed quantitatively using multi-scale curvature and a novel morphometric variable termed Difference of Minimum Curvature (DMC). We used this automated terrain analysis approach to produce a raster map at a scale of 1:6,000,000 showing the distribution of glaciated valleys across Europe and western Asia. The data set has a cell size of 3 arc seconds and consists of more than 40 billion grid cells. Glaciated U-shaped valleys commonly associated with erosion by warm-based glaciers are abundant in the alpine regions of mid Europe and western Asia but also occur at the margins of mountain ice sheets in Scandinavia. The high-level correspondence with field mapping and the fully transferable semantics validate this approach for automated analysis of yet unexplored terrain around the globe and qualify for potential applications on other planetary bodies like Mars.

Multi-scale curvature for automated identification of glaciated mountain landscapes.

Erosion by glacial and fluvial processes shapes mountain landscapes in a long-recognized and characteristic way. Upland valleys incised by fluvial processes typically have a V-shaped cross-section with uniform and moderately steep slopes, whereas glacial valleys tend to have a U-shaped profile with a changing slope gradient. We present a novel regional approach to automatically differentiate between fluvial and glacial mountain landscapes based on the relation of multi-scale curvature and drainage area. Sample catchments are delineated and multiple moving window sizes are used to calculate per-cell curvature over a variety of scales ranging from the vicinity of the flow path at the valley bottom to catchment sections fully including valley sides. Single-scale curvature can take similar values for glaciated and non-glaciated catchments but a comparison of multi-scale curvature leads to different results according to the typical cross-sectional shapes. To adapt these differences for automated classification of mountain landscapes into areas with V- and U-shaped valleys, curvature values are correlated with drainage area and a new and simple morphometric parameter, the Difference of Minimum Curvature (DMC), is developed. At three study sites in the western United States the DMC thresholds determined from catchment analysis are used to automatically identify 5 × 5 km quadrats of glaciated and non-glaciated landscapes and the distinctions are validated by field-based geological and geomorphological maps. Our results demonstrate that DMC is a good predictor of glacial imprint, allowing automated delineation of glacially and fluvially incised mountain landscapes.

Rapid soil production and weathering in the Southern Alps, New Zealand.

Evaluating conflicting theories about the influence of mountains on carbon dioxide cycling and climate requires understanding weathering fluxes from tectonically uplifting landscapes. The lack of soil production and weathering rate measurements in Earth's most rapidly uplifting mountains has made it difficult to determine whether weathering rates increase or decline in response to rapid erosion. Beryllium-10 concentrations in soils from the western Southern Alps, New Zealand, demonstrate that soil is produced from bedrock more rapidly than previously recognized, at rates up to 2.5 millimeters per year. Weathering intensity data further indicate that soil chemical denudation rates increase proportionally with erosion rates. These high weathering rates support the view that mountains play a key role in global-scale chemical weathering and thus have potentially important implications for the global carbon cycle.

A process-based hierarchical framework for monitoring glaciated alpine headwaters.

Recent studies have demonstrated the geomorphic complexity and wide range of hydrologic regimes found in alpine headwater channels that provide complex habitats for aquatic taxa. These geohydrologic elements are fundamental to better understand patterns in species assemblages and indicator taxa and are necessary to aquatic monitoring protocols that aim to track changes in physical conditions. Complex physical variables shape many biological and ecological traits, including life history strategies, but these mechanisms can only be understood if critical physical variables are adequately represented within the sampling framework. To better align sampling design protocols with current geohydrologic knowledge, we present a conceptual framework that incorporates regional-scale conditions, basin-scale longitudinal profiles, valley-scale glacial macroform structure, valley segment-scale (i.e., colluvial, alluvial, and bedrock), and reach-scale channel types. At the valley segment- and reach-scales, these hierarchical levels are associated with differences in streamflow and sediment regime, water source contribution and water temperature. Examples of linked physical-ecological hypotheses placed in a landscape context and a case study using the proposed framework are presented to demonstrate the usefulness of this approach for monitoring complex temporal and spatial patterns and processes in glaciated basins. This approach is meant to aid in comparisons between mountain regions on a global scale and to improve management of potentially endangered alpine species affected by climate change and other stressors.

Glacier and landslide feedbacks to topographic relief in the Himalayan syntaxes.

Despite longstanding research on the age and formation of the Tibetan Plateau, the controls on the erosional decay of its margins remain controversial. Pronounced aridity and highly localized rock uplift have traditionally been viewed as limits to the dissection of the plateau by bedrock rivers. Recently, however, glacier dynamics and landsliding have been argued to retard headward fluvial erosion into the plateau interior by forming dams and protective alluvial fill. Here, we report a conspicuous clustering of hundreds of natural dams along the Indus and the Tsangpo Rivers where these cross the Himalayan syntaxes. The Indus is riddled by hundreds of dams composed of debris from catastrophic rock avalanches, forming the largest concentration of giant landslide dams known worldwide, whereas the Tsangpo seems devoid of comparable landslide dams. In contrast, glacial dams such as river-blocking moraines in the headwaters of both rivers are limited to where isolated mountain ranges intersect the regional snowline. We find that to first-order, high local topographic relief along both rivers corresponds to conspicuously different knickzones and differences in the type and potential longevity of these dams. In both syntaxes, glacier and landslide dams act as a negative feedback in response to fluvial dissection of the plateau margins. Natural damming protects bedrock from river incision and delays headward knickpoint migration, thereby helping stabilize the southwestern and southeastern margins of the Tibetan Plateau in concert with the effects of upstream aridity and localized rock uplift.

Tibetan plateau river incision inhibited by glacial stabilization of the Tsangpo gorge.

A considerable amount of research has focused on how and when the Tibetan plateau formed in the wake of tectonic convergence between India and Asia. Although far less enquiry has addressed the controls on river incision into the plateau itself, widely accepted theory predicts that steep fluvial knick points (river reaches with very steep gradients) in the eastern Himalayan syntaxis at the southeastern plateau margin should erode rapidly, driving a wave of incision back into the plateau. Preservation of the plateau edge thus presents something of a conundrum that may be resolved by invoking either differential rock uplift matching erosional decay, or other mechanisms for retarding bedrock river incision in this region where high stream power excludes the potential for aridity as a simple limit to dissection of the plateau. Here we report morphologic evidence showing that Quaternary depression of the regional equilibrium line altitude, where long-term glacier mass gain equals mass loss, was sufficient to repeatedly form moraine dams on major rivers: such damming substantially impeded river incision into the southeastern edge of the Tibetan plateau through the coupled effects of upstream impoundment and interglacial aggradation. Such glacial stabilization of the resulting highly focused river incision centred on the Tsangpo gorge could further contribute to initiating and accentuating a locus of rapid exhumation, known as tectonic anaeurysm.

Channel and perennial flow initiation in headwater streams: management implications of variability in source-area size.

Despite increasing attention to management of headwater streams as sources of water, sediment, and wood to downstream rivers, the extent of headwater channels and perennial flow remain poorly known and inaccurately depicted on topographic maps and in digital hydrographic data. This study reports field mapping of channel head and perennial flow initiation locations in forested landscapes underlain by sandstone and basalt lithologies in Washington State, USA. Contributing source areas were delineated for each feature using a digital elevation model (DEM) as well as a Global Positioning System device in the field. Systematic source area-slope relationships described in other landscapes were not evident for channel heads in either lithology. In addition, substantial variability in DEM-derived source area sizes relative to field-delineated source areas indicates that in this area, identification of an area-slope relationship, should one even exist, would be difficult. However, channel heads and stream heads, here defined as the start of perennial flow, appear to be co-located within both of the lithologies, which together with lateral expansion and contraction of surface water around channel heads on a seasonal cycle in the basalt lithology, suggest a controlling influence of bedrock springs for that location. While management strategies for determining locations of channel heads and perennial flow initiation in comparable areas could assign standard source area sizes based on limited field data collection within that landscape, field-mapped source areas that support perennial flow are much smaller than recognized by current Washington State regulations.

Soil erosion and agricultural sustainability.

Data drawn from a global compilation of studies quantitatively confirm the long-articulated contention that erosion rates from conventionally plowed agricultural fields average 1-2 orders of magnitude greater than rates of soil production, erosion under native vegetation, and long-term geological erosion. The general equivalence of the latter indicates that, considered globally, hillslope soil production and erosion evolve to balance geologic and climate forcing, whereas conventional plow-based agriculture increases erosion rates enough to prove unsustainable. In contrast to how net soil erosion rates in conventionally plowed fields ( approximately 1 mm/yr) can erode through a typical hillslope soil profile over time scales comparable to the longevity of major civilizations, no-till agriculture produces erosion rates much closer to soil production rates and therefore could provide a foundation for sustainable agriculture.

Planetary science: are there active glaciers on Mars?

Head et al. interpret spectacular images from the Mars Express high-resolution stereo camera as evidence of geologically recent rock glaciers in Tharsis and of a piedmont ('hourglass') glacier at the base of a 3-km-high massif east of Hellas. They attribute growth of the low-latitude glaciers to snowfall during periods of increased spin-axis obliquity. The age of the hourglass glacier, considered to be inactive and slowly shrinking beneath a debris cover in the absence of modern snowfall, is estimated to be more than 40 Myr. Although we agree that the maximum glacier extent was climatically controlled, we find evidence in the images to support local augmentation of accumulation from snowfall through a mechanism that does not require climate change on Mars.