USDA Natural Resources Conservation Service Research Articles

Putting the soil health principles to the test in Iowa

AbstractOne of the most popular soil conservation campaigns is based on the USDA Natural Resource Conservation Service's Soil Health Principles (NRCS‐SHPs). The NRCS‐SHP program identifies four principles—maximize presence of living roots, minimize disturbance, maximize soil cover, and maximize biodiversity—with the underlying assumption that the more principles one follows, the greater improvements in soil health. Despite the popularity of the NRCS‐SHPs, this underlying assumption has not been rigorously tested. To do so, we used nine long‐term experiments all located in central Iowa, but with varying degree of NRCS‐SHP adoption, to determine if greater adoption increases three slow‐changing (maximum water holding capacity, bulk density [BD], and soil organic carbon) and three dynamic (microbial biomass carbon [MBC], potentially mineralizable carbon [PMC], and permanganate oxidizable carbon [POXC]) soil health indicators. We regressed these indicators with a soil health principle score that can scale soil management based on adoption of the NRCS‐SHPs. Of the slow‐changing soil properties, increased adoption of NRCS‐SHPs only decreased soil BD (R2 = 0.22, p = 0.024). On the other hand, increased adoption of NRCS‐SHPs strongly predicted increases in both MBC and PMC and across two sampling dates (R2 > 0.23, p < 0.015); POXC, however, did not increase with greater adoption. The consistent increases in MBC and PMC with greater adoption of NRCS‐SHPs supports their usefulness as sensitive indicators of positive soil health change. Our study provides scientific evidence to support the NRCS‐SHPs concept, improving its usefulness as an extension campaign, and stands as a step toward evidence‐based soil conservation.

Estimation of water inflows to reservoirs of irrigation dams in the Guinea Savannah ecological zone of Ghana

ABSTRACT The study was carried out in the northern Ghana to estimate water inflows to nine reservoirs of irrigation dams for a period of 20 years (1999–2018) using the USDA Natural Resources Conservation Service Curve Number model. The key input parameters of the model were hydrologic soil group, rainfall amount, landuse/landcover, weighted curve number, antecedent moisture condition, and potential maximum soil moisture retention. The annual rainfall within the reservoir catchments was found to vary between 617.20 and 1,382.30 mm. The estimated annual runoff depths ranged from 54.10 to 125.55 mm. A high degree of positive correlation was found between rainfall and runoff depths with a coefficient of determination (R2) ranging from 79.80 to 90.70%. Hydrologic soil groups accounted for about 67.2 and 62.5% of the variation in runoff depth and percentage runoff, respectively. The estimated annual water inflows to the reservoirs ranged from 145,206 ± 125,814 m3/y at Gambibgo to 47,074,634 ± 4,395,860 m3/y at Tono. The variation in the annual water inflows and annual storage capacity recharge among the various reservoirs was noted to be influenced by reservoir size, catchment size, rainfall, and soil characteristics in the reservoir catchments.

A short history of the phosphorus index and Andrew Sharpley's contributions from inception through development and implementation.

In the 1980s, growing recognition of agricultural phosphorus (P) sources to surface water eutrophication led to scrutiny of animal feeding operations. In 1990, the USDA-Natural Resources Conservation Service (NRCS) invited prominent scientists to find a solution. It was at an initial meeting that Dr. Andrew Sharpley suggested that P assessment could be modeled after the Universal Soil Loss Equation, where a matrix of factors influencing P loss would be associated with farm nutrient management recommendations. After codifying the P assessment into the USDA-NRCS 590 Nutrient Management Standard some 10years later, 48 states chose to develop their own P Index. Sharpley, working with many others, helped develop several state P Indices. In 2000, Sharpley secured funding from the USDA-Agricultural Research Service to support the National P Research Project, which conducted in-field P runoff assessments using standardized rainfall simulated studies across 20 states; this allowed individual trials to be aggregated for agroecological regions that were then incorporated into specific state P Indices. Eventually, comparison of P Indices across state boundaries led to a white paper at the behest of USDA-NRCS that resulted in three regional projects evaluating modeling approaches to support or replace P Indices. Sharpley's national umbrella project pointed to shortcomings in water quality models, such as APEX or TBET, as a replacement for state P Indices, which remain a key part of the USDA-590 standard. As a selfless leader, capable of attracting and assembling diverse, productive interdisciplinary teams, Sharpley was essential to the inception, development, and implementation of the P Index.

Effects of forest management on private lands in West Virginia on Cerulean Warblers (Setophaga cerulea) and the avian community

The USDA Natural Resources Conservation Service (NRCS) supports private lands conservation projects across the United States to benefit imperiled focal wildlife species using conservation practices to restore habitat. The Cerulean Warbler Appalachian Forestland Enhancement Project (CWAFEP) was initiated in 2015 to help stabilize or reverse Cerulean Warbler population declines by using forest management to create or enhance breeding habitat on private lands in Appalachian focal areas. We evaluated Cerulean Warbler occupancy on CWAFEP sites treated using NRCS conservation practices to inform adaptive management strategies. We also assessed associated forest focal species’ occupancy and species richness of avian guilds to evaluate the effects of conservation practice implementation on the avian community. We conducted point count surveys at 194 locations on 21 private properties enrolled in the CWAFEP in West Virginia during May – July 2019 and 2020. We compared occupancy among four treatments: reference, pre-treatment, 1-year post-treatment, and 2 – 4 years post-treatment sites. To examine how vegetation structure changes among treatments affected occupancy, we also collected and included vegetation variables. Cerulean Warbler occupancy estimates were not different among treatments, suggesting that post-treatment study sites surveyed did not achieve their goal of increasing Cerulean Warbler occupancy. Cerulean Warbler occupancy decreased by 91 % as elevation increased from 200 to 800 m and increased by 397 % as sapling cover increased from 0 to 100 %. Occupancy for three forest focal species (Blue-gray Gnatcatcher, Eastern Wood-pewee, and Scarlet Tanager) and species richness of four avian guilds also were not different among treatments. Thus, Cerulean Warbler occupancy and selected avian community demographics were not related to recent conservation practice implementation in the short-term (1 – 4 years post-treatment), but there are opportunities to improve NRCS conservation practice implementation for more effective Cerulean Warbler conservation. We suspect that the lack of differences in occupancy and species richness estimates was due to site selection related to ecoregion, small treatment areas, and challenges associated with private lands conservation efforts resulting in insufficient reduction in basal area. If NRCS conservation practices implemented through CWAFEP are going to help reverse Cerulean Warbler population declines, CWAFEP sites need to achieve the recommended basal area range of ∼ 9.2 – 20.7 m 2/ha (40 – 90 ft2/ac) during contract implementation. Our conclusions are critical to updating our knowledge for Cerulean Warbler best management practices and informing future regional conservation implementation.

New indicators of ecological resilience and invasion resistance to support prioritization and management in the sagebrush biome, United States

Ecosystem transformations to altered or novel ecological states are accelerating across the globe. Indicators of ecological resilience to disturbance and resistance to invasion can aid in assessing risks and prioritizing areas for conservation and restoration. The sagebrush biome encompasses parts of 11 western states and is experiencing rapid transformations due to human population growth, invasive species, altered disturbance regimes, and climate change. We built on prior use of static soil moisture and temperature regimes to develop new, ecologically relevant and climate responsive indicators of both resilience and resistance. Our new indicators were based on climate and soil water availability variables derived from process-based ecohydrological models that allow predictions of future conditions. We asked: (1) Which variables best indicate resilience and resistance? (2) What are the relationships among the indicator variables and resilience and resistance categories? (3) How do patterns of resilience and resistance vary across the area? We assembled a large database (n = 24,045) of vegetation sample plots from regional monitoring programs and derived multiple climate and soil water availability variables for each plot from ecohydrological simulations. We used USDA Natural Resources Conservation Service National Soils Survey Information, Ecological Site Descriptions, and expert knowledge to develop and assign ecological types and resilience and resistance categories to each plot. We used random forest models to derive a set of 19 climate and water availability variables that best predicted resilience and resistance categories. Our models had relatively high multiclass accuracy (80% for resilience; 75% for resistance). Top indicator variables for both resilience and resistance included mean temperature, coldest month temperature, climatic water deficit, and summer and driest month precipitation. Variable relationships and patterns differed among ecoregions but reflected environmental gradients; low resilience and resistance were indicated by warm and dry conditions with high climatic water deficits, and moderately high to high resilience and resistance were characterized by cooler and moister conditions with low climatic water deficits. The new, ecologically-relevant indicators provide information on the vulnerability of resources and likely success of management actions, and can be used to develop new approaches and tools for prioritizing areas for conservation and restoration actions.

Soil temperature variations between a Typic Fragiudults and a Typic Paleudults in the Ozark Highlands of Missouri

Soil temperature measurements from a Soil Climate Analysis Network (SCAN) monitoring site in the Ozark Highlands Major Land Resource Area (MLRA 116A) were evaluated on landscapes comprising Typic Fragiudults (Scholten series) and Typic Paleudults (Poynor series). The five soil forming factors were similarfor both soils, with the major difference between the adjacent soils being a fragipan in the Scholten series. Air and soil temperatures were collected from a weather station of the USDA-Natural Resources Conservation Service near the border of the mesic soil temperature regime and udic soil moisture regime zone. The mean annual soil temperature observed in the Scholten soil (13.5° C) was0.5° C cooler than the mean annual soil temperature in the Poynor soil (14.0° C). This study showed little difference in mean soil temperatures between soiltypes from January to April and from August to December. During the months of May, June and July, the Poynor mean soil temperature was higher (by 1.1° C, 1.4° C and 1.2° C, respectively) than the Scholten mean soil temperature.According to this study, it is possible that the mean annual soil temperature of fragipan soils is cooler than adjacent soils with no fragipan properties. Thegreatest differences between mean soil temperature and mean air temperature were observed during the months of November (5.1° C for Scholten soil and 5.3°C for Poynor soil); December (5.0° C for Scholten soil and 4.9° C for Poynor soil); and January (4.5° C for Scholten soil and 4.4° C for Poynor soil). The smallestdifference was during the month of March (0° C for Scholten soil and 0.3° C for Poynor soil). This study also indicated that the mean annual soil temperature in the Ozark Highlands can vary by soil series depending on soil properties affecting heat transfer within pedons.

Spatial and agronomic assessment of water erosion on inland Pacific Northwest cereal grain cropland

The inland Pacific Northwest (PNW) is characterized by high erosion rates attributed to hilly topography, highly erodible silt loam soils, wet winter seasons with frequent freeze-thaw events, and widespread use of conventional tillage practices. Historically, annual water erosion from cropland in the region’s Palouse River basin averaged 20.6 t ha^-1, and more recent rates are 10, 13, and 11 t ha^-1 for the low (<380 mm y^-1), intermediate (380 to 460 mm y^-1), and high (>460 mm y^-1) precipitation zones. Identifying source areas for targeted, effective management requires understanding the factors affecting water erosion, especially how tillage practices and crop rotation interact in various topographic, soil, and climatic settings. The objectives of this study were to (1) understand how hillslope hydrological and water erosion processes are influenced by key environmental factors (soil, climate, and topography) and management practices (tillage and crop rotation), and (2) assess the spatial distribution of soil erosion at the county level and by precipitation zone over the last 30 years. We compiled various combinations of soil, climate, topography, tillage, and crop rotation, and simulated these combinations county by county with the Water Erosion Prediction Project (WEPP) model. Simulated average annual erosion rates were lowest in the low-precipitation zone and highest in the intermediate-precipitation zone, exceeding the USDA Natural Resources Conservation Service tolerable limit (11 t ha^-1) in many cases. Temporally, high precipitation events and fallow periods in the rotation greatly increase erosion. Average annual erosion rates in Whitman County are 13.6, 19.0, and 15.4 t ha^-1 in the three precipitation zones: low (<380 mm y^-1), intermediate (380 to 460 mm y^-1), and high (>460 mm y^-1), respectively. The intermediate-precipitation zone produced a total annual erosion of 4.2 × 10⁶ t, despite having the smallest area. Columbia County has the highest erosion rate with 23.7 t ha^-1 y^-1. Geospatial visualizations of the simulation results reveal critical source areas (“hotspots”) where estimated erosion rates are more than five times the average rates, providing crucial information for, and advancing our understanding of, targeting management and increasing efficiency of conservation practices.

Post‐fire succession of seeding treatments in relation to reference communities in the Great Basin

AbstractQuestionsPost‐fire seeding has been widely implemented in the semiarid Great Basin because natural vegetation recovery may be compromised. Non‐native species are often seeded to rapidly establish perennial cover and compete with invasive annuals. We asked whether seeding treatments with different amounts of native and non‐native species followed different successional trajectories and whether they became more similar to reference communities over time. We considered restoration implications of seed mix choices and reference community options involving: (a) local unburned vegetation; and (b) reference states mapped by the USDA Natural Resources Conservation Service (NRCS) based on soil–vegetation associations.LocationTintic Valley, UT, USA.MethodsFour post‐fire seeding treatments differing by seed mix were installed alongside an unseeded control (USC) at two sites. Two seed mixes were comprised of native species and two were predominantly non‐native. Vegetation was monitored 1–3 and 16–18 years after fire and seeding. Reference communities were characterized and compared using hierarchical clustering. Non‐metric multidimensional scaling and permutation tests were used to determine successional trajectories of post‐fire treatments in relation to reference communities.ResultsLocal unburned reference communities had fewer herbaceous perennials and higher woody cover than NRCS reference communities, suggesting departure from conditions expected under minimal post‐settlement disturbance. USCs became more similar to reference communities over time, though less so at a site with abundant invasive annuals. Trajectories of seeded treatments were driven by seed mix species, with native‐only mixes approaching reference communities more closely than mixes with non‐natives.ConclusionsGradual recovery of reference community composition is possible without seeding but the degree and rate of recovery can vary by site. Seeding can accelerate perennial vegetation recovery but may result in alternative successional trajectories, especially if non‐native species are seeded. Carefully selected reference communities can serve as guides for formulating seed mixes when restoration of natural vegetation is desired.

Lessons Learned from the First 10 Years of the Oaks and Prairies Joint Venture’s Grassland Restoration Incentive Program (GRIP)

The Oaks and Prairies Joint Venture (OPJV) was formed in 2008 as a public-private partnership of agencies and organizations working across jurisdictional boundaries in portions of Texas and Oklahoma, USA. The OPJV’s major focus is reversing declines of bird populations by supporting strategic habitat conservation (biological planning, conservation design, conservation delivery, mission-based monitoring, and assumption-driven research) for northern bobwhite (Colinus virginianus), grasslandobligate species, and their respective habitats. Our objective for this paper is to document and share a decade of lessons learned in developing a partnership-based native grassland conservation program to meet grassland bird conservation targets. We share lessons learned about how to manage partnership-based, large-scale habitat incentive programs to better target project locations and habitat practice types. To establish initial shared purpose, OPJV partners drew from population and habitat objectives in various state, national, and international bird conservation plans, stepped down to ecoregion levels, to establish the OPJV Grassland Bird Conservation Business Plan. The plan has 4 strategies directly contributing to the achievement of OPJV grassland bird biological objectives that are directly supported by OPJV staff or resources (or both). The overall objective for 2015–2025 was 619,978 ha (1,532,000 acres) improved within 40 focal counties, representing 1/3 of all counties in the OPJV. Our main strategy was to provide financial incentives through the OPJV Grassland Restoration Incentive Program (GRIP) to private landowners for conducting beneficial grassland bird habitat management practices. Since inception in 2013, GRIP has treated over 44,515 ha (110,000 acres) on private lands in Texas and Oklahoma, with the goal of maintaining highquality grassland bird habitat on treated hectares for ≥5 years. In 2017, OPJV partners working with USDA Natural Resources Conservation Service, began a 5-year, $6.1 million partnership to provide additional technical and financial assistance to private landowners interested in grassland conservation through the Regional Conservation Partnership Program (RCPP). A project scoring system was designed to strategically encourage individual projects to include prescribed fire—one of the lowest cost practices per hectare—as a recurring practice to maintain program-achieved grassland improvements. Post-inception of the RCPP, the area treated with prescribed fire increased from approximately 809 ha (2,000 acres)/year to 3,237 ha (8,000 acres)/ year, while maintaining average annual hectares of all other beneficial practices. Beginning in 2013, bird point count surveys were conducted annually to monitor northern bobwhite and grassland bird populations, including a subset of points under the National Bobwhite Conservation Initiative (NBCI) Coordinated Implementation Plan. To

WebStart WEPS: WEPS with Remote Data Access and Cloud-Computing Functionality

HighlightsWebStart WEPS is a Java WebStart enabled browser-accessible version of WEPS.This model-as-a-service cloud-based system provides remote access to model inputs and remote model execution.Default QuickPlot reports are provided to quickly visualize model results.MapViewer revisions are provided to improve map-based site selections.Abstract. The Wind Erosion Prediction System (WEPS) is a physical process-based wind erosion model developed by the USDA Agricultural Research Service (USDA-ARS). WEPS simulates daily climate and management-driven changes to the surface, vegetation, and soil. It estimates erosion losses when surface conditions and wind speeds are sufficient for soil movement. WEPS was released in 2010 to the USDA Natural Resources Conservation Service (USDA-NRCS) for assisting land managers in controlling wind erosion, establishing field-level plans for soil conservation, and determining wind erosion susceptibility as a part of national conservation programs to conserve the soil resource. The WEPS interface allows easy user access to national-scale input data. Four primary inputs are required to set up and execute a WEPS run: (1) field dimensions; (2) field location, which automatically determines applicable local climate data; (3) a representative soil; and (4) time series of management practices. These inputs require access to a significant amount of data, which are typically stored locally; however, maintaining these data on every computer running WEPS and keeping them current were problematic for the NRCS. To address these concerns, remote access functionality was incorporated into WEPS to deliver climate and wind data, as well as soil, operation, crop/residue, and management (a date-sequenced list of management operations) records. In addition, WebStart WEPS also features the option of running WEPS components remotely “in the cloud” as web services. The Java WebStart framework provides a simplified delivery mechanism to users’ computers and offers automatic updating capability. Keywords: Cloud services, CSIP, Erosion, Java WebStart, Modeling, WEPS, Wind erosion.

Long‐term database of Beasley Lake Watershed with 25 years of agricultural conservation practices

AbstractBeasley Lake Watershed is an agriculturally influenced drainage basin in western Mississippi that has been intensively studied for 25 years. As part of the USDA Conservation Effects Assessment Project (CEAP), the watershed has archived hydrology, precipitation, and water quality data in order to measure the effects of multiple USDA Natural Resources Conservation Service conservation practices on lake water quality. The long‐term database is available to researchers using a web‐based application, Sustaining the Earth's Watersheds, Agricultural Research Data System (STEWARDS). STEWARDS is a GIS‐based data retrieval application that encompasses spatial and temporal data collected from multiple sites within the watershed. This data note describes information located in the STEWARDS Beasley Lake Watershed database, including hydrology, precipitation, and water quality data. This information is valuable to researchers and agencies beyond the USDA as an available and useful database to improve the understanding of how land‐use practices affect the water quality of shallow lake systems.

Soil Health Response of Histosols to Flooded versus Dry-Fallow Conditions during Summer

Evaluating changes in soil properties associated with flooded fields during the summer months in the Everglades Agricultural Area (EAA) provides us an opportunity to assess the effect of soil management associated with flooded versus dry-fallow field conditions on Histosols. This information will be beneficial to current and potential growers farming flooded rice in south Florida, as well as Extension agents who work on rice and soil conservation agencies such as the USDA Natural Resources Conservation Service (NRCS). This new 6-page publication was written by Jehangir H. Bhadha, Jay Capasso, Abul Rabbany, Nan Xu, and Matthew VanWeelden, and published by the UF/IFAS Department of Soil and Water Sciences.https://edis.ifas.ufl.edu/ss697

Enhancing integration of Indigenous agricultural knowledge into USDA Natural Resources Conservation Service cost-share initiatives

Agricultural management practices drawn from Indigenous agricultural knowledge (IAK) have supported people in the North American desert Southwest for thousands of years. Techniques developed and refined from generation to generation through careful observation and innovation have enhanced the sustainability and resilience of these delicate agroecosystems over millennia. USDA Natural Resources Conservation Service (NRCS) recognized the contributions of IAK practices to Environmental Quality Incentives (EQIP) and the Conservation Stewardship Programs (CSP) in the 2010 <i>Indigenous Stewardship Methods and NRCS Conservation Practices</i> (ISM) handbook. However, during fiscal year 2017 2% of EQIP and CSP contracts went to American Indian farms, which make up 2.9% of the total farms in the United States. NRCS would need to award nearly 400 more contracts to Indigenous farms to achieve proportional representation. This suggests significant potential exists for expanding American Indian participation in these conservation programs but barriers to their participation remain. For example, agriculturalists who wish to employ IAK management practices must go through an ad hoc process defined in the 2010 ISM handbook. This adds further complexity to the application process, in which applicants must navigate unique land tenure/ownership issues and tribal/federal interactions. Here we present examples of Indigenous conservation practices embedded in agricultural systems of Hopi dryland farmers, the La Courte Oreilles Band of Lake Superior Chippewa wild rice (<i>Zizania palustris</i>) harvesters, and Menominee tribal foresters to demonstrate the compatibility of IAK practices with NRCS conservation outcomes and to argue for full inclusion of Indigenous agricultural practices into something equivalent to the NRCS Field Office Technical Guides. Expansion of Indigenous agriculturalists and producers in NRCS programs can help preserve important ecosystems and help support Indigenous cultures and time-tested concepts of stewardship. Incorporation and support of IAK practices is beneficial to all stakeholders because expansion of partnerships between the NRCS and Indigenous agriculturalists and producers will help expand Indigenous conservation and agriculture practices and further the NRCS mission of “Helping People Help the Land.”

Modeling likelihood of farmer participation in the USDA Natural Resources Conservation Service Conservation Technical Assistance program in West Virginia

Food and fiber production on America’s farmlands have a major influence on the environment, rural economies, and healthy communities. Therefore, soil and water conservation practices are critical. Nonetheless, research has shown there are few, if any, universal factors that influence farmer conservation practice adoption. USDA Natural Resources Conservation Service (NRCS) has provided no-fee technical assistance for nearly 100 years through the Conservation Technical Assistance (CTA) program, which encourages farmers to engage in voluntary conservation practices without financial incentives. However, in recent years, funding for CTA, which supports NRCS staffing levels and training, has remained relatively flat. Therefore, the primary objective of this study was to determine the factors that influence farmer participation in the CTA program. Given the need for more comprehensive theoretical approaches in the literature, a holistic theory of change that contemplates individual and institutional factors was developed based on the Asset-Based Community Development (ABCD) approach and Community Capitals Framework (CCF). This theoretical model was used to develop and test hypotheses. Data from a mailed questionnaire were quantitatively analyzed to assess farmer motivations and barriers to participation. Results showed informal training, acreage, land use, viewing the farm as a monetary investment, cost-benefit analysis, income, and the role of NRCS staff as educators to be positive motivators, while culturally driven factors, such as the desire for tidy-looking landscapes, are potential barriers. Future research should continue to refine this theoretical model while also investigating the influence of social groups, farmer and nongovernmental organizational trust levels, peer lending circles, and institutional factors such as NRCS organizational capacity in greater detail.

A spatial analysis of high and low farmer participation in the USDA Natural Resources Conservation Service Conservation Technical Assistance program in West Virginia

The USDA Natural Resources Conservation Service (NRCS) is a federal agency that provides financial and technical assistance to farmers to aid them with soil and water conservation. NRCS offers no-fee technical assistance and conservation planning through the Conservation Technical Assistance (CTA) program, which encourages farmers to engage in voluntary conservation practices without financial incentives. As part of a wider study evaluating farmer participation in the CTA program in West Virginia, and NRCS’s organizational capacity to deliver it, a spatial modeling process was adapted to identify the sample population. This CTA program participation spatial modeling process utilized applied CTA practice points to conduct hot spot analyses, exploratory regression, ordinary least squares regression, geographic weighted regression, and land use analysis in a progressive manner to identify high and low farmer participation in the CTA program at the county level. The purpose of this paper is to explain and discuss that process and how the results were used to acquire a more comprehensive empirical data set, consisting of local interviews and mail survey data, for investigating the many factors that influence participation. Results had the added benefit of finding possible areas for NRCS outreach to underserved farmers. We contend this spatial modeling process uses readily available data sets and easily replicable techniques that contribute a relevant and robust method for soil and water conservation research in general and is highly applicable to other government and nongovernmental conservation programs that seek to identify communities for outreach.

Capability of high-resolution RGB imagery to accurately document residue in row-crop fields

Sustaining agriculture and civilizations requires protecting topsoil from erosion. Residue on the soil surface dissipates energy in raindrops, runoff, and wind, reducing detachment and transport of soil particles. Our objective was to contrast transect residue estimates based on (1) in-field evaluation of 100 evenly spaced points along a 15 m tape; (2) evaluation of imagery of the same tapes obtained at two ground sampling distances: 0.014 and 0.06 cm pixel^–1; and (3) a 100 point grid analysis of 50 contiguous 0.3 × 0.2 m images (0.014 cm pixel^–1) adjacent to the tape. Data were collected from May through early July of 2018 in row-crop fields in four Missouri counties: Audrain, Boone, Callaway, and Cooper. We used data from 60 15.2 m transects in 20 fields. Residue estimates based on field readings of the transect tape ranged from 6% to 99%. Reading images of tapes resulted in a mean decrease of 2.5 percentage points of residue. The bullseye grid point method documented tremendous variability along the transect (mean transect sd = 12.4) and a substantially lower estimate of residue cover compared to field tape readings (mean difference –10.3 percentage points). Consistent with a systematic bias to overestimate residue with the tape transect method, the difference increased with increasing residue for residue &lt;50%, was more pronounced with soybean (<i>Glycine max</i> [L.] Merr.) than corn (<i>Zea mays</i> L.), and the difference could be eliminated by rereading tapes with scrupulous attention to the details of transect methodology. Image-based methods have the potential to improve the accuracy of residue estimates by facilitating methods less prone to reader bias such as the bullseye grid approach. Additionally, to improve accuracy, image-based protocols should be integrated into training and quality control assurance protocols of USDA Natural Resources Conservation Service (NRCS) assessments of residue using transect methods.

Conservation plans and soil and water conservation practice use: Evidence from Iowa

Conservation planning is the primary tool the USDA Natural Resources Conservation Service (NRCS) uses to help farmers manage and protect the nation’s soil, water, air, plant, animal, energy, and human natural resources on privately owned lands. While research studies have investigated a multitude of factors that could possibly influence farmer adoption of conservation practices, no recent research exists examining the relationship between having an NRCS conservation plan and the likelihood of applying conservation practices on the ground. This is surprising given that conservation planning is considered to be the foundation for USDA’s technical and financial assistance to agricultural landowners, and recently both the updated NRCS Strategic Plan and the National Conservation Planning Partnership emphasized the need to enhance and expand conservation planning. In this study we analyzed data from 792 respondents of the 2015 and 2016 collection periods of a panel survey of Iowa farmers to examine the relationship between having an NRCS conservation plan and farmers’ implementation of 10 soil and water conservation practices in four categories: (1) soil health, (2) nitrogen (N) management, (3) structural practices, and (4) cropland converted to perennial crops. The results indicate that farmers who reported having an NRCS conservation plan are significantly more likely to have implemented two conservation practices: no-till and terraces. In addition, there was a significant relationship between the number of times a farmer visited a USDA Service Center for conservation and the likelihood they implemented 5 of the 10 selected practices, particularly in the soil health and structural practice categories. These results suggest that it is not the plan itself, but rather the sustained interaction with natural resource professionals, that makes a difference in the use of conservation practices. Implications of the study results for NRCS conservation planning moving forward in the future are discussed.

Economic dimensions of soil health practices that sequester carbon: Promising research directions

Soil health is a key element in enhancing agricultural production, environmental sustainability, and food system resilience (Farnsworth 2015; Stevens 2018). The USDA Natural Resources Conservation Service (NRCS) defines soil health as “the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans” (Pankhurst et al. 1997; Farnsworth 2015; Bowman et al. 2016). A common theme points to soil health as an indicator of the soil’s ability to support life, withstand environmental stresses, and endure as an important part of a resilient ecosystem. Because one of the key individual components of soil health is carbon (C) in organic matter (Idowu et al. 2009; Morrow et al. 2016), enhancing soil health also has a prominent role to play in addressing climate change (Stockmann et al. 2013; Schipanski et al. 2014; Paustian et al. 2016). Improving soil health is a natural climate solution (NCS) that increases C storage in soils (Poeplau and Don 2015; Griscom et al. 2017; Jian et al. 2020). Given soil health’s key role in sustaining agricultural productivity and enhancing C storage, there is significant interest in promoting …

Soil health conceptualization differs across key stakeholder groups in the Midwest

Stakeholder conceptualizations of soil health inform agricultural decision-making. Currently, diverse sources of soil health knowledge have resulted in divergent conceptualizations of soil health across groups. Using a combination of mail and online surveys of corn (<i>Zea mays</i> L.), soybean (<i>Glycine max</i> [L.] Merr.), and wheat (<i>Tritcum aestivum</i> L.) farmers (<i>n</i> = 89); USDA Natural Resources Conservation Service (NRCS) personnel (<i>n</i> = 134); and agricultural researchers (<i>n</i> = 42) in the Midwest; we (1) investigated how members of these groups perceived prioritization of soil health by farmers, (2) explored conceptual linkages with soil health, and (3) assessed the efficacy of soil testing methods. Farmers ranked soil health as a much higher priority (8.5/10) than NRCS personnel and researchers expected (4.9 and 5.7, respectively). While there were many areas of shared conceptualization, there were also key systematic differences across groups. Use of specific types of soil tests was positively associated with their valuation, with the exception of farmer use of soil health tests. Farmers ranked soil health tests as providing highly valued information but reported low use, suggesting barriers to adoption rather than a lack of interest. These findings have implications for both communication and research strategies for soil health.

WinDAM C: Analysis Tool for Predicting Breach Erosion Processes of Embankment Dams Due to Overtopping or Internal Erosion

HighlightsThe computational models comprising the current version of WinDAM, called WinDAM C, are summarized.WinDAM C estimates the response of an earthen embankment subjected to overtopping or internal erosion.WinDAM C is a model that quantifies erosion/breach processes observed in physical embankment failure tests.Understanding the current technology and limitations provides a basis for further model development.Abstract. Internal erosion and overtopping erosion of earthen embankments are the leading causes for earthen embankment failures. Challenges like reservoir sedimentation, structural deterioration, rodent damage or tree root growth, and changing hazard classification from low to significant or high have arisen with aging dams. To address these challenges, new technology and tools for predicting the performance of homogeneous, cohesive earthen embankments during overtopping or internal erosion are needed. Windows Dam Analysis Modules (WinDAM) is a modular software application developed through collaborative efforts of the United States Department of Agriculture (USDA) Agricultural Research Service (ARS), the USDA-Natural Resources Conservation Service (NRCS), and Kansas State University (KSU) in response to this need. WinDAM uses a simple storage routing model to simulate flow through a reservoir and incorporates algorithms for predicting the progression of erosion resulting from embankment overtopping or flow through an internal discontinuity in the embankment. These algorithms are based on existing literature and data and observations from physical model experiments of homogeneous, cohesive embankments conducted by scientists at the USDA-ARS Hydraulic Engineering Research Unit in Stillwater, Oklahoma. The resulting computational model is a simplified representation of the observed process of progressive erosion that may lead to embankment breach. This paper reviews the components of the erosion/breach process and the way in which these components are quantified and integrated into the current WinDAM software, WinDAM C. The scope of application of the software, limitations, and computational assumptions are also discussed. Keywords: Breach, Dams, Erodibility, Erosion Process, Failure, Internal erosion, Model, Overtopping, Piping.