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At least 775 records · Page 43Linked to original sources
USGS2009

Modeling to evaluate the response of savanna-derived cropland to warming–drying stress and nitrogen fertilizers

Many savannas in West Africa have been converted to croplands and are among the world’s regions most vulnerable to climate change due to deteriorating soil quality. We focused on the savanna-derived cropland in northern Ghana to simulate its sensitivity to projected climate change and nitrogen fertilization scenarios. Here we show that progressive warming–drying stress over the twenty-first century will enhance soil carbon emissions from all kinds of lands of which the natural ecosystems will be more vulnerable to variation in climate variables, particularly in annual precipitation. The carbon emissions from all croplands, however, could be mitigated by applying nitrogen fertilizer at 30–60 kg N ha − 1 year − 1 . The uncertainties of soil organic carbon budgets and crop yields depend mainly on the nitrogen fertilization rate during the first 40 years and then are dominated by climate drying stress. The replenishment of soil nutrients, especially of nitrogen through fertilization, could be one of the priority options for policy makers and farm managers as they evaluate mitigation and adaptation strategies of cropping systems and management practices to sustain agriculture and ensure food security under a changing climate.

Climatic Change↗
USGS1956

Silica in hot-spring waters

The silica in hot-spring waters and in a few cold waters was studied by moans of the colorimetrie ammonium-molybdate method of analysis. Murata found in 1947 that only a part of the total silica in aged samples of high-silica waters was determinable by the colorimetric method. Weitz , franck And schuchard later showed that ammonium molybdate reacts readily with the monomeric form of silica (probably H 4 SiO 4 ) but very slowly with polymeric silica. If the colorimetric measurement is completed in two or three minutes, only the monomer is determined. Nearly all silica of hot springs is in the monomeric form. Solubility equilibrium exists between dissolved (monomeric) and amorphous silica. For the hot springs that were studied, the solubility is about 315 p.p.m. at 90°C and 110 p.p.m. at 25°C, which is very similar to Krauskopf's experimental data. Monomeric silica polymerizes so slowly to colloidal silica that many waters are supersaturated with respect to amorphous silica. The rate of polymerization is influenced by pH, temperature, degree of supersaturation, presence of previously formed colloidal and gelatinous silica and contact with opal and other substances. Supersaturated acid waters and alkaline waters with less than 100% supersaturation tend to remain supersaturated almost indefinitely, with little or no change. Precipitation of colloidal silica is favoured by high temperature and contact with opal. Many connate and other ground waters, including some thermal springs, are much below saturation with respect to amorphous silica, probably because low-solubility quartz and chalcedony have been precipitating. Quartz is favoured by relatively high temperature, slow rale of precipitation, and low degree of supersaturation, and is believed to form by deposition of monomeric molecules. Chalcedony is probably deposited when the degree of supersaturation is moderately high and the rate of deposition is relatively fast. The ranges of temperature over which quartz and chalcedony deposit no doubt overlap, but, if other factors are equal, quartz is favoured by high temperature. Opal is favoured by relatively low temperature and rapid rate of precipitation. Although opal has probably been deposited at temperatures as high as 140°C, it is unstable and is slowly converted to chalcedony or quartz. Water that is saturated with respect to opal is highly supersaturated with respect to quartz. Opal is probably formed from monomeric or more probably, the smaller polymeric molecules of silica, retaining some of their water content. Evidence is lacking for the direct conversion of gelatinous silica to opal. Some differences in solubility probably exist between amorphous opal and opal that shows X-ray patterns like that of cristobalite. The suggestion is made that clay minerals form by combination of monomeric silica and a comparable form of monomeric alumina, which must have very low solubility in waters within the pH range of 5 to 9. Because of the abundance and relatively high solubility of silica, the proposed reaction, dissolved alumina + dissolved silica ⇌ clay, is ordinarily displaced strongly to the right in hydrothermal alteration and in ordinary soil formation. With removal of free silica, aided by tropical rainfall and temperatures, the reaction may be displaced to the left by dissolution and removal of silica from the system. Alumina, because of its very low solubility, remains as bauxite.

Geochimica et Cosmochimica Acta↗
USGS2009

Vadose water

Vadose water is subsurface water between the land surface and the saturated zone below the water table. The vadose (or unsaturated) zone includes soil water, which is immediately available to the biosphere. It acts as a controlling agent in the transmission of water and other substances between various components of the earth system: aquifers, land surface, bodies of water, atmosphere, and so on. As an accessible body of material near the earth's surface, the vadose zone is a focus of much human activity, including agriculture, mining, construction, and waste disposal. Thus, it is affected by anthropogenic modifications of its chemical and physical components. Modern hydrology must consider interactions not only among the natural constituents, but also with a wide variety of contaminants, including pesticides, fertilizers, irrigation wastewater, sewage, toxic chemicals, radioactive substances, bacteria, mine wastes, and organic liquids.

Book chapter↗
USGS2015

Dynamic response of desert wetlands to abrupt climate change

Desert wetlands are keystone ecosystems in arid environments and are preserved in the geologic record as groundwater discharge (GWD) deposits. GWD deposits are inherently discontinuous and stratigraphically complex, which has limited our understanding of how desert wetlands responded to past episodes of rapid climate change. Previous studies have shown that wetlands responded to climate change on glacial to interglacial timescales, but their sensitivity to short-lived climate perturbations is largely unknown. Here, we show that GWD deposits in the Las Vegas Valley (southern Nevada, United States) provide a detailed and nearly complete record of dynamic hydrologic changes during the past 35 ka (thousands of calibrated 14 C years before present), including cycles of wetland expansion and contraction that correlate tightly with climatic oscillations recorded in the Greenland ice cores. Cessation of discharge associated with rapid warming events resulted in the collapse of entire wetland systems in the Las Vegas Valley at multiple times during the late Quaternary. On average, drought-like conditions, as recorded by widespread erosion and the formation of desert soils, lasted for a few centuries. This record illustrates the vulnerability of desert wetland flora and fauna to abrupt climate change. It also shows that GWD deposits can be used to reconstruct paleohydrologic conditions at millennial to submillennial timescales and informs conservation efforts aimed at protecting these fragile ecosystems in the face of anthropogenic warming.

Nevada↗
USGS2026

Initial condition uncertainty exerts a large and persistent influence on model simulations of ecosystem carbon dynamics in California

Uncertainties in terrestrial ecosystem models limit their predictive power. Efforts to reduce projection error have rarely focused on constraining uncertainty in the initial state of the ecosystem, however, despite evidence that matching model initial conditions to real-world observations reduces overall model bias. Here we use an integrated land change and carbon gain-loss model to evaluate the influence of initial condition uncertainty on simulations of California wildland ecosystems during the years 1985–2020. We generated 36 initial conditions scenarios by varying the source data used to initialize state variables and then ran simulations based on each of these scenarios under a constant set of historical conditions. We found that discrepancies in initial forest extent and initial forest age among scenarios generated wide uncertainty ranges in model estimates of terrestrial ecosystem carbon stocks and flux rates at the outset of the simulation period, but differences in initial forest composition had no impact. Over time, forest age became more homogeneous across model scenarios leading to exponential rates of decline in the uncertainty ranges of live biomass and dead wood carbon but little to no impact on uncertainties in litter and soil organic carbon. Uncertainties in individual carbon flux rates were consistent with uncertainties in their source pools. In contrast, model estimates of ecosystem carbon balance demonstrated a shift in system behavior not apparent in trends for individual carbon stocks and fluxes. Specifically, estimates of ecosystem carbon balance converged across scenarios for the first 20 years of the simulation period but then began to diverge at an accelerating rate, possibly due to weakened resilience to the increased frequency and severity of climate-driven disturbances. Our results demonstrate that uncertainty in the initial state of the system can have large and persistent impacts on the predictability of ecosystem carbon dynamics, and that ongoing shifts in external forcing by climate and climate-driven disturbances can exacerbate these impacts.

California↗
USGS2022

A framework for integrating inferred movement behavior into disease risk models

Movement behavior is an important contributor to habitat selection and its incorporation in disease risk models has been somewhat neglected. The habitat preferences of host individuals affect their probability of exposure to pathogens. If preference behavior can be incorporated in ecological niche models (ENMs) when data on pathogen distributions are available, then variation in such behavior may dramatically impact exposure risk. Here we use data from the anthrax endemic system of Etosha National Park, Namibia, to demonstrate how integrating inferred movement behavior alters the construction of disease risk maps. We used a Maximum Entropy (MaxEnt) model that associated soil, bioclimatic, and vegetation variables with the best available pathogen presence data collected at anthrax carcass sites to map areas of most likely Bacillus anthracis (the causative bacterium of anthrax) persistence. We then used a hidden Markov model (HMM) to distinguish foraging and non-foraging behavioral states along the movement tracks of nine zebra ( Equus quagga ) during the 2009 and 2010 anthrax seasons. The resulting tracks, decomposed on the basis of the inferred behavioral state, formed the basis of step-selection functions (SSFs) that used the MaxEnt output as a potential predictor variable. Our analyses revealed different risks of exposure during different zebra behavioral states, which were obscured when the full movement tracks were analyzed without consideration of the underlying behavioral states of individuals. Pathogen (or vector) distribution models may be misleading with regard to the actual risk faced by host animal populations when specific behavioral states are not explicitly accounted for in selection analyses. To more accurately evaluate exposure risk, especially in the case of environmentally transmitted pathogens, selection functions could be built for each identified behavioral state and then used to assess the comparative exposure risk across relevant states. The scale of data collection and analysis, however, introduces complexities and limitations for consideration when interpreting results.

Etosha National Park↗
USGS2014

A synopsis of short-term response to alternative restoration treatments in sagebrush-steppe: the SageSTEP project

The Sagebrush Steppe Treatment Evaluation Project (SageSTEP) is an integrated long-term study that evaluates ecological effects of alternative treatments designed to reduce woody fuels and to stimulate the herbaceous understory of sagebrush steppe communities of the Intermountain West. This synopsis summarizes results through 3 yr posttreatment. Woody vegetation reduction by prescribed fire, mechanical treatments, or herbicides initiated a cascade of effects, beginning with increased availability of nitrogen and soil water, followed by increased growth of herbaceous vegetation. Response of butterflies and magnitudes of runoff and erosion closely followed herbaceous vegetation recovery. Effects on shrubs, biological soil crust, tree cover, surface woody fuel loads, and sagebrush-obligate bird communities will take longer to be fully expressed. In the short term, cool wet sites were more resilient than warm dry sites, and resistance was mostly dependent on pretreatment herbaceous cover. At least 10 yr of posttreatment time will likely be necessary to determine outcomes for most sites. Mechanical treatments did not serve as surrogates for prescribed fire in how each influenced the fuel bed, the soil, erosion, and sage-obligate bird communities. Woody vegetation reduction by any means resulted in increased availability of soil water, higher herbaceous cover, and greater butterfly numbers. We identified several trade-offs (desirable outcomes for some variables, undesirable for others), involving most components of the study system. Trade-offs are inevitable when managing complex natural systems, and they underline the importance of asking questions about the whole system when developing management objectives. Substantial spatial and temporal heterogeneity in sagebrush steppe ecosystems emphasizes the point that there will rarely be a “recipe” for choosing management actions on any specific area. Use of a consistent evaluation process linked to monitoring may be the best chance managers have for arresting woodland expansion and cheatgrass invasion that may accelerate in a future warming climate.

Rangeland Ecology and Management↗
USGS2000

Factors associated with plant species richness in a coastal tall-grass prairie

In this study we examine the factors associated with variations in species richness within a remnant tall-grass prairie in order to gain insight into the relative importance of controlling variables. The study area was a small, isolated prairie surrounded by wetlands and located within the coastal prairie region, which occurs along the northwestern Gulf of Mexico coastal plain. Samples were taken along three transects that spanned the prairie. Parameters measured included micro-elevation, soil characteristics, indications of recent disturbance, above-ground biomass (including litter), light penetration through the plant canopy, and species richness. Species richness was found to correlate with micro-elevation, certain soil parameters, and light penetration through the canopy, but not with above-ground biomass. Structural equation analysis was used to assess the direct and indirect effects of micro-elevation, soil properties, disturbance, and indicators of plant abundance on species richness. The results of this analysis showed that observed variations in species richness were primarily associated with variations in environmental effects (from soil and microtopography) and were largely unrelated to variations in measures of plant abundance (biomass and light penetration). These findings suggest that observed variations in species richness in this system primarily resulted from environmental effects on the species pool. These results fit with a growing body of information that suggests that environmental effects on species richness are of widespread importance.

Journal of Vegetation Science↗
USGS1993

Ground-water quality at the Management Systems Evaluation Area (MSEA) near Princeton, Minnesota, 1991

The northern cornbelt sand-plains Management Systems Evaluation Area (MSEA) program is a multiagency, multistate initiative to evaluate the effects of modified and prevailing fanning systems on water quality in a sand-plain area in Minnesota and at satellite areas in North and South Dakota, and Wisconsin (Delin and others, 1992). The primary objective of the northern cornbelt sand-plains MSEA is to evaluate the effects of ridge-tillage practices in a corn and soybean farming system on ground-water quality. The Minnesota MSEA program is a cooperative study primarily between the U.S. Department of Agriculture-Agricultural Research Service, the University of Minnesota Soil Science Department, and the U.S. Geological Survey. The Minnesota Pollution Control Agency and the Department of Geology and Geophysics at the University of Minnesota are also cooperating in the evaluation of ground-water quality at the MSEA.

Minnesota↗
USGS2008

Spatial Distribution of Ground-Water Recharge Estimated with a Water-Budget Method for the Jordan Creek Watershed, Lehigh County, Pennsylvania

This report presents the results of a study by the U.S. Geological Survey, in cooperation with the Pennsylvania Geological Survey, to illustrate a water-budget method for mapping the spatial distribution of ground-water recharge for a 76-square-mile part of the Jordan Creek watershed, northwest of Allentown, in Lehigh County, Pennsylvania. Recharge was estimated by using the Hydrological Evaluation of Landfill Performance (HELP) water-budget model for 577 landscape units in Jordan Creek watershed, delineated on the basis of their soils, land use/land cover, and mean annual precipitation during 1951-2000. The water-budget model routes precipitation falling on each landscape unit to components of evapotranspiration, surface runoff, storage, and vertical percolation (recharge) for a five-layer soil column on a daily basis. The spatial distribution of mean annual recharge during 1951-2000 for each landscape unit was mapped by the use of a geographic information system. Recharge simulated by the water-budget model in Jordan Creek watershed during 1951-2000 averaged 12.3 inches per year and ranged by landscape unit from 0.11 to 17.05 inches per year. Mean annual recharge during 1951-2000 simulated by the water-budget model was most sensitive to changes to input values for precipitation and runoff-curve number. Mean annual recharge values for the crop, forest, pasture, and low-density urban land-use/land-cover classes were similar (11.2 to 12.2 inches per year) but were substantially less for high-density urban (6.8 inches per year), herbaceous wetlands (2.5 inches per year), and forested wetlands (1.3 inches per year). Recharge rates simulated for the crop, forest, pasture, and low-density urban land-cover classes were similar because those land-use/land-cover classes are represented in the model with parameter values that either did not significantly affect simulated recharge or tended to have offsetting effects on recharge. For example, for landscapes with forest land cover, values of runoff-curve number assigned to the model were smaller than for other land-use/land-cover classes (causing more recharge and less runoff), but the maximum depth of evapotranspiration was larger than for other land-use/ land-cover classes because of deeper root penetration in forests (causing more evapotranspiration and less recharge). The smaller simulated recharge for high-density urban and wetland land-use/land-cover classes was caused by the large values of runoff-curve number (greater than 90) assigned to those classes. The large runoff-curve number, however, certainly is not realistic for all wetlands; some wetlands act as areas of ground-water discharge and some as areas of recharge. Simulated mean annual recharge computed by the water-budget model for the 53-square-mile part of the watershed upstream from the streamflow-gaging station near Schnecksville was compared to estimates of recharge and base flow determined by analysis of streamflow records from 1967 to 2000. The mean annual recharge of 12.4 inches per year simulated by the water-budget method for 1967-2000 was less than estimates of mean annual recharge of 19.3 inches per year computed from the RORA computer program and base flow computed by the PART computer program (15.1 inches per year). In theory, the water-budget method provides a practical tool for estimating differences in recharge at local scales of interest, and the watershed- average recharge rate of 12.4 inches per year computed by the method is reasonable. However, the mean annual surface runoff of 4.5 inches per year simulated by the model is unrealistically small. The sum of surface runoff and recharge simulated by the water-budget model (16.9 inches per year) is 7 inches per year less than the streamflow measured at the gaging station near Schnecksville (23.9 inches per year) during 1967-2000, indicating that evapotranspiration is overestimated by the water-budget model by that amount. This discrepancy ca

Scientific Investigations Report↗
USGS2015

PRMS-IV, the precipitation-runoff modeling system, version 4

Computer models that simulate the hydrologic cycle at a watershed scale facilitate assessment of variability in climate, biota, geology, and human activities on water availability and flow. This report describes an updated version of the Precipitation-Runoff Modeling System. The Precipitation-Runoff Modeling System is a deterministic, distributed-parameter, physical-process-based modeling system developed to evaluate the response of various combinations of climate and land use on streamflow and general watershed hydrology. Several new model components were developed, and all existing components were updated, to enhance performance and supportability. This report describes the history, application, concepts, organization, and mathematical formulation of the Precipitation-Runoff Modeling System and its model components. This updated version provides improvements in (1) system flexibility for integrated science, (2) verification of conservation of water during simulation, (3) methods for spatial distribution of climate boundary conditions, and (4) methods for simulation of soil-water flow and storage.

Techniques and Methods↗
USGS2025

Discovery of an intact Quaternary paleosol, Georgia Bight, USA

A previously buried paleosol was found on the continental shelf during a study of sea floor scour, nucleated by large artificial reef structures such as vessel hulks, barges, train cars, military vehicles, etc., called “scour nuclei”. It is a relic paleo-land surface of sapling-sized tree stumps, root systems, and fossil animal bone exhumed by scour processes active adjacent to the artificial reef structure. Over the span of five research cruises to the site in 2022–2024, soil samples were taken using hand excavation, PONAR grab samplers, split spoon, hollow tube auger, and a modified Shelby-style push box. High-definition (HD) video was taken using a Remotely Operated Vehicle (ROV) and diver-held cameras. Radiocarbon dating of wood samples returned ages of 42,015–43,417 calibrated years before present (cal yrBP). Pollen studies, together with the recovered macrobotanical remains, support our interpretation of the site as a freshwater forested wetland whose keystone tree species was Taxodium distichum —bald cypress. The paleosol was identified as an Aquult, a sub-order of Ultisols where water tables are at or near the surface year-round. A deep (0.25 m+) argillic horizon comprised the bulk of the preserved soil. Comparable Ultisols found in Georgia wetlands include Typic Paleaquult (Grady and Bayboro series) soils.

Georgia↗
USGS2022

Natural infrastructure in dryland streams (NIDS) can establish regenerative wetland sinks that reverse desertification and strengthen climate resilience

In this article we describe the natural hydrogeomorphological and biogeochemical cycles of dryland fluvial ecosystems that make them unique, yet vulnerable to land use activities and climate change. We introduce Natural Infrastructure in Dryland Streams (NIDS), which are structures naturally or anthropogenically created from earth, wood, debris, or rock that can restore implicit function of these systems. This manuscript further discusses the capability of and functional similarities between beaver dams and anthropogenic NIDS, documented by decades of scientific study. In addition, we present the novel, evidence-based finding that NIDS can create wetlands in water-scarce riparian zones, with soil organic carbon stock as much as 200 to 1400 Mg C/ha in the top meter of soil. We identify the key restorative action of NIDS, which is to slow the drainage of water from the landscape such that more of it can infiltrate and be used to facilitate natural physical, chemical, and biological processes in fluvial environments. Specifically, we assert that the rapid drainage of water from such environments can be reversed through the restoration of natural infrastructure that once existed. We then explore how NIDS can be used to restore the natural biogeochemical feedback loops in these systems. We provide examples of how NIDS have been used to restore such feedback loops, the lessons learned from installation of NIDS in the dryland streams of the southwestern United States, how such efforts might be scaled up, and what the implications are for mitigating climate change effects. Our synthesis portrays how restoration using NIDS can support adaptation to and protection from climate-related disturbances and stressors such as drought, water shortages, flooding, heatwaves, dust storms, wildfire, biodiversity losses, and food insecurity.

Science of the Total Environment↗
USGS2003

Vulnerability of ground water to contamination, northern Bexar County, Texas

The Trinity aquifer, composed of Lower Cretaceous carbonate rocks, largely controls the ground-water hydrology in the study area of northern Bexar County, Texas. Discharge from the Trinity aquifer recharges the downgradient, hydraulically connected Edwards aquifer one of the most permeable and productive aquifers in the Nation and the sole source of water for more than a million people in south-central Texas. The unconfined, karstic outcrop of the Edwards aquifer makes it particularly vulnerable to contamination resulting from urbanization that is spreading rapidly northward across an "environmentally sensitive" recharge zone of the Edwards aquifer and its upgradient "catchment area," composed mostly of the less permeable Trinity aquifer. A better understanding of the Trinity aquifer is needed to evaluate water-management decisions affecting the quality of water in both the Trinity and Edwards aquifers. A study was made, therefore, in cooperation with the San Antonio Water System to assess northern Bexar County's vulnerability to ground-water contamination. The vulnerability of ground water to contamination in this area varies with the effects of five categories of natural features (hydrogeologic units, faults, caves and (or) sinkholes, slopes, and soils) that occur on the outcrop and in the shallow subcrop of the Glen Rose Limestone. Where faults affect the rates of recharge or discharge or the patterns of ground-water flow in the Glen Rose Limestone, they likewise affect the risk of water-quality degradation. Caves and sinkholes generally increase the vulnerability of ground water to contamination, especially where their occurrences are concentrated. The slope of land surface can affect the vulnerability of ground water by controlling where and how long a potential contaminant remains on the surface. Disregarding the exception of steep slopes which are assumed to have no soil cover the greater the slope, the less the risk of ground-water contamination. Because most soils in the study area are uniformly thin, they have only minimal effect on the vulnerability of ground water to contamination. The results of hydrogeologic mapping during the present study divide the outcrop of the Glen Rose Limestone into five mappable intervals, labeled (youngest to oldest) A through E. Of these intervals, only the middle (C) and the lowermost (E) generally provide appreciable permeability. The vulnerability assessment provided herein was determined by combining the presumed effects of selected natural features (with individual vulnerability ratings ranging from 0 through 35) using a grid-based, multilayer system of digital datasets and geographic information system analysis. The resulting vulnerability map comprises composite vulnerability ratings that range from 26 through 104. The relatively less vulnerable areas those containing no faults, sinkholes, or caves occupy about 92 percent of the study area. The most vulnerable areas are those containing both a fault and one or more caves. The distribution of the most vulnerable areas which trend from southwest to northeast, roughly parallel to the Balcones fault zone occur mainly where faults intersect caves.

Texas↗
USGS2026

Ecovoltaic solar energy development creates novel microclimate, temperature, and soil moisture patterns under solar panels in a warm desert

Background: As solar energy development expands in desert regions, new installation practices and solar technologies seek to balance ecosystem conservation and energy generation (ecovoltaics). The Gemini Solar Project, a large ecovoltaic facility located in the northeastern Mojave Desert, employed low impact installation methods to reduce disturbance of the desert ecosystem within arrays of bifacial panels mounted on solar tracking systems. We evaluated microclimate and environmental conditions across five locations: four within-facility microsites (underneath solar panels, east and west panel driplines, and interspaces between panel rows) and one in the undisturbed desert outside the facility. Results: Under panel microsites experienced lower solar radiation and evaporative demand than panel driplines, and driplines experienced lower solar radiation and evaporative demand than interspaces and undisturbed desert outside the facility. Air temperature was similar among microsites, whereas soil surface temperature was highest in interspaces and lower in under-panel and dripline microsites due to diurnal panel shading. Soil temperature was higher under panels compared to interspaces from March to September and lower in other months, and higher during daytime and lower at nighttime periods. Panel tracking and the more frequent occurrence of afternoon precipitation promoted higher soil moisture in west driplines. Water redistribution was also influenced by soil hydraulic conductivity—deep soils experienced greater west dripline soil moisture, whereas shallow soils experienced surface water pooling and greater soil moisture in the west dripline and under solar panels. Conclusions: Gemini’s ecovoltaic design promotes microclimate heterogeneity, moderating some environmental conditions while intensifying others, and often differing from fixed panel facilities with higher disturbance. This research provides critical information to balance renewable energy expansion and ecological function in warm deserts.

Nevada↗
USGS2025

Increased soil greenhouse gas emissions from the combined use of cover crops and no‐tillage in producer‐ managed fields

Cover crop adoption offers multiple benefits and climate mitigation potential for agroecosystems, but is still an underutilized conservation practice. Recently, the combined use of cover cropping plus no-tillage (CCNT) has been increasingly promoted to achieve its synergistic effectiveness. Yet, how this combined practice affects soil greenhouse gas (GHG) emission remains a topic of debate. Existing studies are predominantly based on research-managed settings and often fail to assess all three major GHGs of carbon dioxide (CO 2 ), nitrous oxide (N 2 O), and methane (CH 4 ). To address these knowledge gaps, this study conducted a 30-month monitoring from producer-managed fields to quantify the soil greenhouse gas responses to CCNT compared to no-tillage (NT) alone. The findings showed that CCNT increased the soil global warming potential (GWP) by 15.2% relative to NT. CO 2 is the main contributor, accounting for over 91.7% of the total GWP. On average, the daily fluxes of CO 2 , N 2 O, and CH 4 were increased by 16.2%, 32.3%, and 55.6% under CCNT, respectively. Meteorological variables explained 85.3% of the CO 2 increase and 46.1% of the N 2 O increase associated with CCNT. Furthermore, two types of CCNT practices differed in GHG emission responses, though both strategies significantly reduced nitrogen losses. These quantitative results, derived from actual production systems, provide informed decision-making among local producers regarding the adoption of cover crops. Moreover, this field-based evidence offers a robust empirical foundation for future modeling efforts aimed at assessing the ecological benefits of cover crops under varying climatic and soil conditions.

Indiana↗
USGS2023

The future of Indiana's water resources: A report from the Indiana climate change impacts assessment

Indiana’s water resources—in streams and lakes, in plants and soils, and underground—are a critical component of the state’s economy and well-being. Availability of this important resource is driven by precipitation and temperature patterns, both of which have shifted in recent decades, and is also highly influenced by how we manage natural and human systems. As local temperatures continue to rise and rainfall patterns shift, managing the multiple water needs of communities, natural systems, recreation, industry, and agriculture will become increasingly difficult. Ensuring that enough water is available in the right places and at the right times will require awareness of Indiana’s changing water resources and planning at regional and state levels. This report from the Indiana Climate Change Impacts Assessment (IN CCIA) applies climate change projections for the state to explore how continued changes in Indiana’s climate are going to affect all aspects of water resources, including soil water, evaporation, runoff, snow cover, streamflow, drought, and flooding. The findings presented here are primarily based on the IN CCIA Water Resources Working Group technical report (Cherkauer et al., 2021) and the IN CCIA report Indiana’s Past and Future Climate (Widhalm et al., 2018).

Indiana↗
USGS2011

Enhanced decomposition offsets enhanced productivity and soil carbon accumulation in coastal wetlands responding to climate change

Coastal wetlands are responsible for about half of all carbon burial in oceans, and their persistence as a valuable ecosystem depends largely on the ability to accumulate organic material at rates equivalent to relative sea level rise. Recent work suggests that 5 elevated CO2 and temperature warming will increase organic matter productivity and the ability of marshes to survive sea level rise. However, we find that organic decomposition rates increase by about 12% per degree of warming. Our measured temperature sensitivity is similar to studies from terrestrial systems, twice as high as the response of salt marsh productivity to temperature warming, and roughly equivalent to the productivity response associated with elevated CO2 10 in C3 marsh plants. Therefore, enhanced CO2 and warmer temperatures may actually make marshes less resilient to sea level rise, and tend to promote a release of soil carbon. Simple projections indicate that elevated temperatures will increase rates of sea level rise more than any acceleration in organic matter accumulation, suggesting the possibility of a positive feedback between 15 climate, sea level rise, and carbon emissions in coastal environment

Biogeosciences Discussions↗