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The article discusses the Area IV Soil Conservation Districts Cooperative Research Farm located near Mandan, North Dakota, U.S. Topics mentioned include the history and influence of one long-term cropping systems research in northern Great Plains to improve cropping system sustainability, the goals set by the Research Advisory Committee served as guide the past 30 years, and the major accomplishments such as management practices to reduce soil erosion.

There are concerns that restored grasslands currently under the Conservation Reserve Program (CRP) will experience increased soil erosion when they are returned to crop production. Our objective was to compare runoff, erosion, and erodibility on CRP land converted to annum hay production (permanent hayed, PH) and crop production under conventional-till (preplant disk tillage, CT) and no-till (NT) management. Erosion study was conducted in central North Dakota on Typic Argiustoll soil 6 yr after the CRP land had been converted to hay production and crop production with a spring wheat (Triticum aestivura L.) -winter wheat-dry pea (Pisum sativum L.) rotation. Runoff volumes and soil loss (by alum precipitation of sediment) were measured on 1.5 by 5 m bordered plots on 4% slope under a rainfall simulator delivering 1- to 3-h rains at 50 or 75 mm h-1, followed by three rains of 20 min or less at rates from 25 to 125 mm h-1. Erodibility was calculated from ratios and regressions of soil loss rates versus runoff rates measured at relative steady state. Runoff rates from 50 and 75 mm h-1 rains for CT, NT, and PH averaged 9, 12, and 21 mm h-1, respectively, and supported soil loss rates of 20, 7, and 8 g m-2 h-1. Erodibility of undisturbed CT, NT, and PH was 1.65, 0.29, and 0.28 g m-2 mm-1, respectively, showing NT did not differ from PH and that CT management increased erodibility six-fold above PH. Thorough disk tillage increased erodibility three-fold over CT, 15-fold over NT, and nine-fold over PH. Complete, nondisturbing residue removal increased erodibility less than tillage, from 1.2 times for CT to 2.5 times for NT. Chemically weeded NT exhibited the same Iow erodibility as the grassland PH treatment under the conditions of study-4% land slope, above average precipitation, and a residueproductive crop rotation. However, erodibility of tilled NT was significantiy higher than that of tilled PH, showing the higher inherent stability of grassland surface soil with its perennial plant root structures. [ABSTRACT FROM AUTHOR]

Presents a study which evaluated the four approaches to point-scale assessment of soil quality. Materials and methods; Description of assessment approaches; Development of data classes; Comparison of the assessment approaches; Results and discussion.

During periods of no or low crop growth in dryland cropping systems, tillage can reduce residue coverage and thereby elevate wind erosion risk. We measured wind erosion on a silt loam, Haplustoll soil in North Dakota (456 mm precipitation yr–1) in response to levels of tillage applied once in spring during fallow following a small grain–sunflower (Helianthus annuus L.) rotation. Treatments were no‐tillage (NT), one‐pass tandem disk tillage (TDT), and two‐pass offset disk tillage (ODT). Erosion flux was measured with sediment samplers near peripheries of >1‐ha replicated plots from May through September 2003 and 2004. Soil losses in ODT, TDT, and NT were 12.0, 4.8, and 2.1 Mg ha–1, respectively, in 2003 and 2.6, 1.6, and 1.4 Mg ha–1 in 2004. The greatest loss, 12.0 Mg ha–1, was equivalent to 1‐mm soil depth. The two‐ to fivefold greater erosion in 2003, a year with 2 mo of <30% of average precipitation, appears linked to a decline in residue coverage. Coverage remained about the same in NT and increased in tilled treatments during 2004 with more average precipitation. Our measurements of wind erosion have shown how the residue‐destroying effects of a single tillage event can be considerably exacerbated by a moderate, seasonal drought. This indicates the critical importance of NT for limiting soil and residue disturbance and reducing wind erosion risk from drought‐affected plant growth failure in semiarid cropping systems. Core Ideas: Wind erosion loss was two‐ to sixfold greater under disk tillage than no‐tillage.Seasonal drought led to less weed growth and residue coverage.Seasonal drought resulted in two‐ to fivefold greater wind erosion loss.The Revised Wind Erosion Equation (RWEQ) model indicated that residue coverage conferred the greatest resistance to erosion. [ABSTRACT FROM AUTHOR]

A global, unified dataset on Soil Organic Carbon (SOC) changes under perennial crops has not existed till now. We present a global, harmonised database on SOC change resulting from perennial crop cultivation. It contains information about 1605 paired-comparison empirical values (some of which are aggregated data) from 180 different peer-reviewed studies, 709 sites, on 58 different perennial crop types, from 32 countries in temperate, tropical and boreal areas; including species used for food, bioenergy and bio-products. The database also contains information on climate, soil characteristics, management and topography. This is the first such global compilation and will act as a baseline for SOC changes in perennial crops. It will be key to supporting global modelling of land use and carbon cycle feedbacks, and supporting agricultural policy development. Design Type(s) data integration objective • data collection and processing objective • factorial design Measurement Type(s) amount of carbon atom in soil Technology Type(s) digital curation Factor Type(s) climate • Species • experimental condition • age Sample Characteristic(s) Brazil • cultivated environment • Canada • United States of America • New Zealand • Italy • Germany • Cameroon • India • Sri Lanka • Venezuela • Kingdom of Denmark • Republic of Ireland • French Republic • United Kingdom • Kingdom of Spain • Costa Rica • Ethiopia • Ghana • Indonesia • Mexico • Nigeria • Republic of South Africa • Portuguese Republic • China • Malaysia • Turkey • Israel • Sweden • italy • Georgia • Puerto Rico • Tanzania • Australia Machine-accessible metadata file describing the reported data (ISA-Tab format) [ABSTRACT FROM AUTHOR]

Conservation agriculture is often assumed to reduce soil N2O emissions. Yet, studies analyzing the specific effect of conservation agriculture practices on N2O emissions give contradictory results. Herein, we synthesized a comprehensive database on the three main conservation agriculture practices (cover crops, diversified crop rotations, and no-till and/or reduced tillage (NT/RT)) to elucidate the role of conservation practices on N2O emissions. Further, we used a random meta-forest approach to identify the most important predictors of the effects of these practices on soil N2O emissions. Averaged across all comparisons, NT/RT significantly decreased soil N2O emissions by 11% (95% CI: –19 to –1%) compared to conventional tillage. The reductions due to NT/RT were more commonly observed in humid climates and in soils with an initial carbon content < 20 g kg–1. The implementation of cover crops and diversified crop rotations led to variable effects on soil N2O emissions. Cover crops were more likely to reduce soil N2O emissions at neutral soil pH, and in soils with intermediate carbon (~20 g kg–1) and nitrogen (~3 g kg–1) contents. Diversified crop rotations tended to increase soil N2O emissions in temperate regions and neutral to alkaline soils. Our results provide a comprehensive predictive framework to understand the conditions in which the adoption of various conservation agriculture practices can contribute to climate change mitigation. Combining these results with a similar mechanistic understanding of conservation agriculture impacts on ecosystem services and crop production will pave the way for a wider adoption globally of these management practices. [ABSTRACT FROM AUTHOR]

Understanding controls on soil organic carbon (SOC) will be crucial to managing soils for climate change mitigation and food security. Climate exerts an overarching influence on SOC, affecting both carbon (C) inputs to soil and soil physicochemical properties participating in C retention. To test our hypothesis that climate, C inputs, and soil properties would differently affect particulate organic carbon (POC) and mineral-associated organic carbon (MAOC), we sampled 16 agricultural sites (n = 124 plots) in the United States, ranging in climate (mean annual precipitation (MAP)—potential evapotranspiration (PET; MAP-PET)), soil pH (5.8–7.9), and soil texture (silt + clay = 13–96%). As MAP-PET increased, soils increased in oxalate-extractable iron (FeO) and aluminum (AlO), decreased in exchangeable calcium (Caex) and magnesium (Mgex), and received greater C inputs. Soil physicochemical properties did not strongly predict POC, confirming the relative independence of this SOC fraction from the soil matrix. In contrast, MAOC was well predicted by combining AlO + [1/2]FeO with Caex + Mgex in a 'matrix capacity index', which performed better than individual soil physicochemical properties across all pH levels (r > 0.79). Structural equation modeling indicated a similar total effect of MAP-PET on MAOC and POC, which was mediated by total C inputs and the matrix capacity index for MAOC but not POC. Our results emphasize the need to separately conceptualize controls on MAOC and POC and justify the use of a unified soil matrix capacity index for predicting soil MAOC storage. [ABSTRACT FROM AUTHOR]

Integrated crop–livestock (ICL) systems have shown potential to provide a variety of environmental benefits including soil carbon (C) increases relative to conventional row cropping systems. However, studies documenting C dynamics of ICL systems in the northern Great Plains are lacking relative to other agroecosystems. Soil carbon dioxide (CO2) efflux, crop biomass, and soil organic matter (SOM) pools were monitored over 3 years in an ICL rotation (corn [Zea mays L.]/soybean [Glycine max L.]–spring wheat [Triticum aestivum L.] + cover crop–cover crop) with fall grazing, a conventional cropping system rotation (corn–spring wheat–soybean) and fall grazed and ungrazed mixed‐grass pasture near Mandan, ND. Cropped treatments were under no‐till management. Annual aboveground crop residue biomass C was similar in the ICL and conventional systems, while less in the grazed pasture (4.18, 3.83, and 1.21 Mg C ha−1 year−1 respectively; p = 0.039). Annual soil CO2 efflux was greater in the ICL, grazed, and ungrazed pasture systems than the conventional system (8.05, 8.73, 8.25, and 5.81 Mg C ha−1 year−1, respectively; p < 0.001). Among crop phases in the ICL and conventional cropping systems, cover crops contributed to greater CO2 efflux in the spring and fall. SOM and C mineralization were greater at 0–5 cm in the ICL system compared to the conventional cropping system (6.6% vs. 6.3%, p = 0.028 and 248 vs. 184 mg CO2–C kg−1, p < 0.001, respectively). Interseeded cover crops in ICL systems can contribute increased root respiration and enhanced SOM pools relative to conventional cropping systems under semiarid conditions. Core Ideas: Soil carbon (C) dynamics in integrated crop–livestock (ICL) systems are not well understood.Soil carbon dioxide (CO2) efflux and labile pools of soil organic matter (SOM) were evaluated over 3 years.Soil CO2 efflux was greater in the ICL system compared to conventional cropping.SOM and C mineralization were also greater in the ICL system compared to conventional cropping.Interseeded cover crops in ICL systems can enhance soil C pools and biological activity. [ABSTRACT FROM AUTHOR]

A correction to the article "Diversification and ecosystem services for conservation agriculture: Outcomes from pastures and integrated crop-livestock systems" that was published in the March 11, 2013 issue is presented.

Abstract: Biologically derived emissions of carbon dioxide (CO2) and nitrous oxide (N2O) at 0 °C vary with soil depth during soil thawing. Micro-site soil properties, especially those which influence porosity and substrate availability, also vary with depth and may help explain gas emissions. Intact soil cores collected to a depth of 80 cm from an undisturbed prairie Mollisol in central North Dakota were uniformly subjected to distinct temperature steps during a simulated soil thaw (−15 to 5 °C) and sampled for CO2 and N2O emissions throughout the soil profile. Emission data were fit to a first order exponential equation (E = αe βT ). Cores were then analyzed in 10 cm depth increments for micro-site properties including root length and mass, aggregation, and organic substrate availability (available, aggregate-protected and mineral-bound pools). Both CO2 and N2O emissions at 0 °C declined exponentially with depth. Emissions of CO2 and N2O at 0 °C were strongly related to root length (R 2 = 0.80 and 0.76, respectively), root mass (R 2 = 0.56 and 0.74), large macroaggregate mass (R 2 = 0.63 and 0.54), and aggregate-protected organic matter (R 2 > 0.57), while available organic matter was related to CO2 (R 2 > 0.60) and not N2O. When CO2 and N2O emissions were normalized by available and aggregate-protected carbon pools, respectively, nutrient use efficiency increased significantly with depth. Results suggest CO2 and N2O emissions are (1) positively influenced by the rhizosphere and (2) differentially affected by substrate pool or location. CO2 emissions were more positively affected by available substrate, while N2O emissions were more positively affected by less labile, aggregate-protected substrate. [Copyright &y& Elsevier]

Abstract: The fate of carbon (C) and nitrogen (N) belowground is important to current and future climate models as soils warm in northern latitudes. Currently, little is known about the sensitivity of microbial respiration to temperature changes at depths below 15 cm. We used whole-core (7.6 cm dia. × 90 cm) laboratory incubations to determine if temperature response quotients (Q 10) for CO2 and N2O varied with depth for undisturbed prairie while plants were senescent and clipped at the surface. We collected intact soil cores from an undisturbed prairie in central North Dakota and uniformly subjected them to freezing (5 to −15 °C) and thawing (−15 to 5 °C). We measured rates of CO2 and N2O emissions at 5 °C temperature increments at 0, 15, 30, 45, 60, and 75 cm depths. During freezing, active and sterilized core emissions occurred only between 0 and −10 °C. During thawing, a simple first-order exponential model, E = αeβT, fit observed CO2 and N2O emissions (R 2 = 0.91 and 0.99, respectively). Parameter estimates for β were not significantly different across depths for CO2 and for N2O (Q 10 = 4.8 and 13.7, respectively). Parameter estimates for α (emissions when temperature is 0 °C) exponentially declined with depth for both gases for similar depth-response curves. Stepwise regressions of soil properties on α parameter estimates indicated emissions of CO2 and N2O at 0 °C during thawing were positively correlated (R 2 > 0.6) with soil porosity. Results indicate pedogenic properties associated with depth may not necessarily influence temperature response curves during thawing but will affect emissions at 0 °C for both CO2 and N2O. [Copyright &y& Elsevier]

• We developed water budgets for 18 Long-Term Agroecosystem Research sites. • We estimated uncertainty of all the water budget components. • The average water budget uncertainty was 25% of precipitation. • Uncertainties were greatest for percolation and evapotranspiration. • LTAR sites span a 0.4 – 1.1 evaporative fraction and a 0.8 – 4.8 aridity index. Understanding the movement and storage of water within agricultural landscapes as functions of management and climate is essential for more efficient and sustainable water use. However, knowledge of water storage and fluxes on U.S. agricultural lands is largely incomplete. The Long-Term Agroecosystem Research (LTAR) network provides a unique and geographically diverse set of agricultural study sites in the United States. The objectives of this study were to: 1) characterize the hydrologic variability across the LTAR network; 2) identify data gaps in the water budgets across the LTAR network; and 3) identify opportunities to leverage the LTAR network to improve understanding of water budgets across agricultural landscapes. For each of the 18 LTAR sites, we developed water budgets on an average annual basis. Uncertainty propagation methods combined individual component uncertainties to calculate an overall water budget uncertainty. Datasets length ranged from three to 50 years. The network covers a range of precipitation from 240 to 1400 mm yr−1, evapotranspiration from 228 to 1080 mm yr−1, and surface runoff and subsurface flow from negligible to 560 mm yr−1. However, uncertainties of where all the water is going remained high, in part because soil water storage and downward movement of water were often neglected or measured for very short periods, resulting in average water budget uncertainty of 25% of the water inputs. More accurate measurement of the major inputs and outputs, and direct measurement of water content and percolation are key to understanding how agricultural lands affect terrestrial water budgets. [ABSTRACT FROM AUTHOR]

Cropland agriculture in the northern Great Plains is challenged by variable weather, agricultural intensification, and competing use for energy development. Innovative cropland practices that address these challenges are needed to ensure regional agriculture can sustainably meet future food, fuel, and fiber demand. In response to this need, the Northern Plains Long-Term Agroecosystem Research Network site established a cropland experiment in 2019 that contrasts prevailing and alternative practices at plot and field scales over a proposed 30-year time frame. The experimental site is located on the Area IV Soil Conservation Districts Cooperative Research Farm near Mandan, ND. Cropping practices for the first 6 years of the experiment were developed with input from stakeholders and include a 3-year crop rotation of spring wheat (Triticum aestivum L.), corn (Zea mays L.), and soybean (Glycine max L.) with cover crops (alternative practice) and without (prevailing practice). The prevailing practice also involves the removal of crop residue, while a second alternative practice of perennial forages is included in the plot-scale experiment. Biophysical measurements are made at both spatial scales at frequencies aligned with approved methods for each agronomic and environmental metric. Findings from the first 6 years of the experiment will help identify tradeoffs associated with cover crop use and residue removal in dryland cropping systems. In the future, the experiment will adopt a knowledge co-production approach whereby researchers and stakeholders will work collaboratively to identify problems, implement research, and interpret results., (© 2024 The Authors. Journal of Environmental Quality published by Wiley Periodicals LLC on behalf of American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Soybean ( Glycine max (L.) Merr.) planting has increased in central and western North Dakota despite frequent drought occurrences that limit productivity. Soybean plants need high photosynthetic and transpiration rates to be productive, but they also need high water use efficiency when water is limited. Crop residues and cover crops in crop rotations may improve soybean drought tolerance in northern Great Plains. We aimed to examine how a management practice that included cover crops and residue retention impacts agronomic, ecosystem water and carbon dioxide flux, and canopy-scale physiological attributes of soybeans in the northern Great Plains under drought conditions. The experiment consisted of two soybean fields over two years with business- as -usual (no-cover crops and spring wheat residue removal) and aspirational management (cover crops and spring wheat residue retention) during a drought year. We compared yield; aboveground biomass; green chromatic coordinates, and CO 2 and H 2 O fluxes from eddy covariance, Phenocam images, and ancillary micrometeorological measurements. These measurements were used to derive ecosystem-scale physical, and physiological attributes with the 'big leaf' framework to diagnose underlying processes. Soybean yields were 29 % higher under drought conditions in the field managed in a system that included cover crops and residue retention. This yield increase was associated with a 5 day increase in the green-chromatic-coordinate defined maturity phenophase, increasing agronomic and intrinsic water use efficiency by 27 % and 33 %, respectively, increasing water uptake, and increasing the rubisco-limited photosynthetic capacity (V cmax25 ) by 42 %. The inclusion of cover crops and residue retention into a cropping system improved soybean productivity because of differences in water use, phenology timing, and photosynthetic capacity. These results suggest that farmers can improve soybean productivity and yield stability by incorporating cover crops and residue retention into their management suite because these practices to facilitate more aggressive water uptake., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Global warming potential (GWP) estimates from agroecosystems are valuable for understanding management effects on climate regulation services. However, GWP estimates are complex, including attributes with high spatiotemporal variability. Published GWP estimates from cropland were compiled and methodological attributes known to influence GWP were extracted. Results revealed considerable variation in approaches to estimate GWP. Among carbon balance methods, respiration methods were used most frequently (33%), followed by soil carbon stock change over time (30%). Twenty-six percent of studies did not account for carbon change in GWP estimates. Duration of gas flux measurements ranged from 0.5 to 60 months, with weekly and sub-weekly sampling most common (34% and 33%, respectively). Carbon dioxide equivalent conversion factors generally aligned with Intergovernmental Panel on Climate Change recommendations through 2014 but diverged thereafter. This review suggests the need for increased transparency in how GWP estimates are derived and communicated. Presentation of key metadata alongside GWP estimates is recommended., (© 2023 The Authors. Journal of Environmental Quality published by Wiley Periodicals LLC on behalf of American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.)