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A critical question is whether there are agricultural management practices that can attain the multiple management goals of increasing yields, preventing nutrient losses, and suppressing greenhouse gas (GHG) emissions. No-till and manure application methods, such as manure injection, can enhance nutrient retention, but both may also enhance emissions of nitrous oxide (N 2 O), a powerful GHG. We assessed differences in soil N 2 O and carbon dioxide (CO 2 ) emissions, nitrate and ammonium retention, and crop yield and protein content under combinations of vertical-till, no-till, manure injection, and manure broadcast without incorporation in a corn (Zea mays L.) silage system. During the growing seasons of 2015-2017, GHG emissions and soil mineral nitrogen (N) were measured every other week or more frequently after management events. Crop yield and protein content were measured annually at harvest. No-till reduced CO 2 emissions but had no impact on N 2 O emissions relative to vertical-till. Manure injection increased N 2 O and CO 2 emissions, with the magnitude of this effect being greatest for 1 mo post-application. Manure injection also increased soil ammonium and nitrate but did not increase yield or crop quality relative to broadcast application. Similarly, tillage did not affect crop yield or protein content. Despite the tradeoffs between mineral N retention and elevated GHG emissions, manure injection in no-till systems benefits farmers by reducing soil carbon losses as CO 2 , retaining mineral N, and maintaining crop yields and quality., (© 2020 The Authors. Journal of Environmental Quality © 2020 American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.)

Uncontrolled proliferation of eastern redcedar tree (Juniperus virginiana) in the Midwest United States requires new alternatives for utilization of waste wood, such as mulching, that promotes efficient tree management by landowners. Similarly, efficient use of manure from animal feeding operations in cropping systems can reduce negative environmental impacts and increase cropland productivity. The objectives of this study were to quantify the nitrogen (N) and carbon (C) decomposition rates, availability, and effects on soil chemical properties of eastern redcedar wood chips (WC), cattle manure (CM), and the combination of cattle manure and wood chips (MW). A 120-day incubation and a 12-month field experiment were conducted in Nebraska. In the incubation study, CM decomposed the fastest, followed by MW and WC. At the end of the experiment, WC induced N immobilization. In the field experiment, most decomposition for all amendments occurred during the period between May and August (spring/summer). Decomposition was most rapid for CM and WC with 44% and 55% organic-C loss by mass, respectively. Approximately, 40% of the organic N in CM mineralized during the 1-year field study. Wood chips induced N immobilization after 6 months for shallow soil layers compared to control (no amendment) but did not induce N immobilization when combined with manure. Changes in soil organic matter concentration due to amendment application were not observed at any stages of the field experiment, likely due to the length of the experiment. However, consecutive applications of comingled MW may provide benefits of C contribution to the soil without inducing N limitations., (© 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.)

The Wisconsin Central Sands is home to large scale vegetable production on sandy soils and managed with frequent irrigation, fertigation, and widespread nitrogen fertilizer application, all of which make the region highly susceptible to nitrate loss to groundwater. While the groundwater is used as the primary source of drinking water for many communities and rural residences across the region, it is also used for irrigation. Considering the high levels of nitrate found in the groundwater, it has been proposed that growers more accurately account for the nitrate in their irrigation water as part of nitrogen management plans. Our objectives were to 1) determine the magnitude of nitrate in irrigation water, 2) quantify the spatiotemporal variability of nitrate, and 3) determine key predictors of nitrate concentration in the region. We sampled irrigation water from 38 fields across six farms from 2018 to 2020. Across the 3 years of our study, nitrate concentration varied more across space than time. On average, our samples were tested at 19.0 mg L -1 nitrate-nitrogen, or nearly two times the U.S. Environmental Protection Agency (EPA) threshold for safe drinking water, equivalent to 48.1 kg ha -1 of applied nitrate-nitrogen with 25.4 cm (or 10 in.) of irrigation. To better understand the spatiotemporal variability in nitrate levels, week of sampling, year, well depth, well casing, and nitrogen application rate were analyzed for their role as predictor variables. Based on our linear mixed effects model, nitrogen application rate was the greatest predictor of the nitrate concentration of irrigation water (p < 0.05)., (© 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.)

Nutrient circularity can help supply chain participants meet sustainability targets. Across the segmented beef supply chain, opportunity exists to reinforce and introduce nutrient circularity by recycling surplus manure nutrients from cattle feedlots to lands where cattle feed is produced. We describe four datasets developed to evaluate options in U.S. and Canadian beef systems. The datasets delineate three "circular manuresheds," each encompassing a hay-grazing landscape where beef cattle are raised on grazingland and supplemented with hay grown nearby, and the distant feedlots where those cattle produce manure nutrients for potential import back to the hayfields. We selected the hay-grazing landscapes of New Mexico, USA; Florida, USA; and western Canada (Manitoba, Saskatchewan, Alberta, British Columbia) because of their significant grazingland production and potential to substitute feedlot manure for commercial fertilizer on hayfields. In each circular manureshed, the manure nutrients from major feedlot destinations could supply a considerable proportion of the P used by hay for grazing cattle: 34% of the P requirements in New Mexico, 36% in Florida, and 6% in western Canada. The average distance to return the resource was 647 km for New Mexico, 1,884 km for Florida, and 1,587 km for western Canada. These magnitudes and distances suggest that the New Mexico circular manureshed may be the most economically viable in the current agri-food system, but this reflects only part of a greater, multi-factor assessment of tradeoffs. The circular manureshed concept provides a platform for simultaneous consideration of competing factors for sustainability via circularity., (© 2022 Her Majesty the Queen in Right of Canada. 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. Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)