Research Project: Increasing the Productivity and Resilience to Climate Variability of Agricultural Production Systems in the Upper Midwest U.S. while Reducing Negative Impact on the Environment

Location: Soil and Water Management Research

2021 Annual Report

Objectives
1. Assess the environmental impacts of crop management practices that have the potential to improve soil health and decrease greenhouse gas emissions in the Upper Midwest. a. Develop a perennialized row crop system that reduces the environmental footprint of agriculture and improves its resilience, without adverse impacts on water usage and profitability. b. Develop new knowledge regarding soil nitrogen cycling and nitric and nitrous oxide production mechanisms. c. Develop new knowledge of chemical triggering compounds of microbial activity. 2. Increase nutrient use efficiency and reduce nutrient losses to leaching, runoff and atmospheric emissions in Upper Midwest cropping systems. a. Develop improved methods to quantify and to reduce losses of reactive N gases from fertilized cropping systems. b. Evaluate manure management practices for improvement of nutrient cycling and reduction of reactive nitrogen losses on large dairies.

Approach
All the objectives of this project have a common focus on quantifying the impacts of management practices, including crop rotation/cover crops, irrigation, and synthetic N fertilizer or manure amendments, on GHG emissions and nutrient availability for crop uptake or susceptibility to loss to the environment. The different objectives complement each other in several ways. In order to gain insights from multiple perspectives, the methods for each objective range across scales, including large field and larger plot studies (sub-objective 1a); replicated small-plots (2a); soil column mesocosms (2b); and laboratory microcosms (1b, 1c). The same set of soil types representing a range of Minnesota agricultural soils from across the state, including soil from both field experiments (1a and 2a), will be used in the microcosm and mesocosm experiments (1b, 1c and 2b). Thus, results from the three laboratory experiments each of which have different primary objectives, will inform and help to interpret results of the other lab studies; and results from the lab experiments under more controlled conditions will inform results of the field experiments that are subject to dynamic climate conditions. Both of the field experiments (1a and 2a) will measure greenhouse gas emissions and ammonia volatilization losses from cropping systems under similar soil types (the same soil series) but with different management regimes, which may also allow for cross-site comparison of results. This research also complements efforts within several national projects and initiatives, including the Greenhouse Gas Reduction through Agricultural Carbon Enhancement (GRACEnet), Resilient Economic Agricultural Practices (REAP), Dairy Agro-ecosystem Working Group (DAWG) and Long-Term Agricultural Research (LTAR) networks; and as such will involve collaboration with several colleagues from other ARS locations, universities and other organizations.

Progress Report
Subobjective 1a. We have tested and refined a companion cropping system in which corn and soybeans can be repeatedly planted into a perennial ground cover of kura clover. A novel rotary zone tillage unit was obtained and shown to be superior to conventional strip tillage units for row establishment, and a nitrogen (N) rate study was conducted to determine optimal N fertilizer rate for corn planted into a pure kura stand and separately for corn planted into a stand that had corn planted into it the previous year. Notably, we found that when planted into a pure kura stand, no fertilizer was needed. In fiscal year 2020, an experiment was initiated to further determine best practices for initial row establishment, comparing the rotary zone tillage tool against an improved conventional strip till unit, and also against chemical row establishment with herbicide, which has been used by some practitioners. Data have been collected that demonstrate substantially higher infiltration rates in the living mulch system versus conventional corn/soy production. These and other data have been shared with the Minnesota Board of Water and Soil Resources (BOWSR), and they have ruled that the living mulch system qualifies as perennial cover, which is required along all waterways in the state under the Minnesota Buffer Law. Guidance was also provided to state researchers who are testing the living mulch system for water quality protection. Subobjective 1b. The first manuscript resulting from the soil incubation experiments was revised to address reviewer comments and published. This manuscript reported the soil incubation data in the absence of a nitrification inhibitor, and compared the data to a newly formulated model, the two-step nitrification model (2SN). The 2SN model is the first soil process model to account for ammonia toxicity effects on both steps of nitrification, urea hydrolysis, pH changes, ammonium sorption, ammonia volatilization, and production of nitric oxide and nitrous oxide gases across a broad temperature range of 5 to 30 degrees C. A second manuscript was prepared which reported the corresponding soil incubation data in the presence of the nitrification inhibitor dicyandiamide (DCD). This manuscript reported further developments to the 2SN model which account for the inhibitory effects of DCD on the first step of nitrification (ammonia oxidation) coupled to first-order DCD decomposition across the same temperature range. The analysis also indicated that DCD had at least two unintended consequences on soil nitrogen cycling; increased ammonia volatilization, which is a negative consequence because it increases nitrogen losses to the environment, and increased nitrite oxidation, which is a positive consequence because it suppresses nitrite accumulation which can promote nitric and nitrous oxide gas production. Across the lifetime of the project, this subobjective provided comprehensive datasets comprising measurements of several chemical species in multiple soils at five temperatures with and without a nitrification inhibitor combined with new model development. The results provide new insights into soil nitrogen cycling that can help explain field-level observations, and a new modeling framework that can be further developed and integrated with other larger systems models. Subobjective 1c. The laboratory incubations showed that the fingerprint of microbially-produced volatile organic compounds (mVOCs) is related to the residue type undergoing decomposition and that the number of identifiable mVOCs increase with the complexity of the substrate and with soil microbial biomass diversity. The data also showed that the distribution of mVOCs is altered by the presence of biochar and its sorption capacity as well as the release of biochar-specific organic compounds during the incubation. While inconsistencies remain in the ability to forecast the impact of biochar on soil mineralization processes using chemical species fingerprinting, the data suggest the soil microbial pool could be affected by biochar’s release and/or sorption of microbial signaling compounds. This includes biochar’s interaction with water vapor, which could reduce microbial mineralization due to the desiccation-signaling that a reduced water vapor concentration would trigger. The data also showed that biochar’s ability to sorb compounds is altered by oxidation during its exposure to the soil environment which could affected material’s sorption capacity either positively or negatively. To support these analysis, customized R-scripts were developed which can evaluate mass spectra data utilizing the online PubChem database (https://pubchem.ncbi.nlm.nih.gov). These scripts allow more complete compound identification beyond the standard (Agilent ChemStation NIST) library and permit evaluation of the spectral fitting using more sophisticated diagnostic algorithms (i.e., H-bond Acceptor Count, 3-D Feature Count, and Structural Complexity Score). A stable isotope mass spectrometer (IRMS) was also installed within the St. Paul, Minnesota ARS unit which will be used for improved tracing of carbon cycling, which is particularly envisioned to aid Long-Term Agroecosystem (LTAR) research efforts, and more generally to improve mechanistic-level research for nitrogen cycling. Sub-objective 2a. The final year of the project involved completing the analysis of the data collected during the previous two years of field experimentation and preparing these data for publication. The last two years of data included a total of six site-years of data: two site-years each for irrigated corn and potato production in a loamy sand soil in Becker, Minnesota, and two site-years of non-irrigated corn production in a silt loam soil in St. Paul, Minnesota. During each site-year, the effects of contrasting nitrogen fertilizer management strategies on crop performance and nitrogen losses in the form of nitrous oxide gas emissions and nitrate leaching below the root zone which were measured using flux chambers and porous cup lysimeters, respectively, in replicated plot studies. The nitrogen management strategies evaluated included conventional fertilizer (urea and ammonium) by itself which was compared to the co-application of conventional fertilizer together with different types of amendments, alone or in combination. The amendments included different types of microbial inhibitors and microbial stimulants designed to reduce N losses to the environment and/or enhance crop N uptake. For purposes of analysis and reporting, the data were divided by crop, so that the two site-years of data from the potato system were analyzed separately from the four site-years of data from the corn systems. The potato data were submitted for peer-review and accepted for publication during fiscal year 2021. The results showed that use of a recently developed nitrification inhibitor (DMPSA), which is designed to be more stable in soil than other available nitrification inhibitors, consistently reduced nitrous oxide emissions by at least 40%. Moreover, when DMPSA was combined with the urease inhibitor NBPT, nitrous oxide emissions were reduced by more than 60% and nitrate leaching was also reduced by 25% compared to conventional fertilizer. Analysis of the data from the corn systems is still underway, but some important findings have emerged. Similar to the potato system, nitrous oxide emissions were reduced with the DMPSA+NBPT combination in one of two years. In the rainfed corn, all the amendments examined, except NBPT by itself, reduced nitrous oxide emissions compared with conventional fertilizer. Subobjective 2b. One manuscript describing the column leaching experiment is being re-submitted for peer-review. A second manuscript, which reports nitrogen (N) and phosphorus (P) losses from manure and non-manure sources across a range of soils, is also being prepared for submission for peer-review. In related research on release of nutrients (N and P) from dairy manure under snowmelt conditions, another year of data was collected at collaborator’s sites in Minnesota and Wisconsin and added to a larger body of data that is being analyzed for future submission and publication. Collaborators include an ARS scientist in Marshfield, Wisconsin, and partners at the University of Minnesota and University of Wisconsin. Over the course of the project, laboratory experiments measured the amounts of P leached when undisturbed columns containing topsoil (15-cm depth) varying in texture (sandy loam, silt loam, clay loam, and clay soils) and varying in initial soil test P (STP) values were amended with mineral P sources versus semi-solid dairy manure. Results indicated that P leaching is a substantial loss pathway, losses were greater in soils having greater initial STP values and greater preferential pathways (soils with greater clay content). Losses were also greater when leaching occurred closer to time of P application, and for mineral P versus manure sources of P. Losses were as great as 30% of applied P when leaching commenced immediately with clay soils. Leached P concentrations and loads were greatest to least for these sources: dry mineral, liquid mineral, semi-solid dairy manure. Leaching volume drove load; concentrations remained constant with volume applied. Related research on the effect of temperature on nutrient release from dairy manure to water and on the effects of placement of dairy manure within a snowpack was also conducted. Findings showed that cold temperatures do not decrease nutrient release and that nutrient release is not affected by placement within a snowpack. Laboratory extraction data can be used to estimate nutrient release from manure during snowmelt, and solid manure may release less P during snowmelt than liquid manures. Further study of soil sorption parameters is needed to improve predictive models of P leaching.

Accomplishments
1. The efficacy of the nitrification inhibitor dicyandiamide deteriorates with increasing temperature and varies for different nitrogen forms. Dicyandiamide (DCD) is a widely used soil amendment designed to prevent nitrogen (N) losses to the environment. When applied to soil, DCD slows down the microbial process of nitrification which converts fertilizer N into molecular forms of N that are more readily lost from the soil-plant system. However, little is known about the simultaneous effects of DCD on multiple chemical forms of N, or its effectiveness over broad temperature ranges. ARS researchers at St. Paul, Minnesota, quantified the efficacy of DCD for reducing nine different soil N metrics over a temperature range of 5 to 30 degrees C. The ability of DCD to prevent the formation of nitrate, an important water pollutant, deteriorated rapidly with increasing temperature, while the formation of other N forms, including nitrite and nitric oxide, was inhibited by DCD even at higher temperature. These results will help land managers optimize their use of DCD by accounting for its responsiveness to temperature, and thereby help to reduce N losses to the environment.

2. Current methods to measure biochar surface chemistry are inadequate to properly make optimal agricultural use of biochar. Biochar is a type of charcoal that when added to soil could help to store carbon and decrease the release of fertilizers into ground water and greenhouse gas emissions into the atmosphere. Before biochar can be efficiently used, better characterization of its surface chemistry is needed, because surface chemistry controls many of biochar’s beneficial effects. ARS researchers at St. Paul, Minnesota, conducted research that compared different laboratory methods for analyzing biochar surface chemistry. The results showed that different methods gave very different results. For example, solid-state 13C Nuclear Magnetic Resonance (NMR) had a better ability than synchrotron-based X-ray Absorption Near-Edge Structure (XANES) to differentiate aromatic carbon structure, indicating that caution must be taken when comparing studies that use different methods. The results demonstrate the need to develop standardized guidance for how to best analyze biochar chemistry, which will help scientists to more accurately determine how biochar can be managed to optimize its potential benefits to soil health and crop productivity.

3. Continuous corn silage production in dairy systems results in soil carbon loss even when manure is returned to the field at recommended rates. Maintaining greater amounts of carbon (C) in soil can help to reduce carbon dioxide levels in the atmosphere and is also beneficial for soil fertility, water conservation and other soil health metrics. The return of manure to soils has the potential to store C and thereby reduce the greenhouse gas footprint of dairy production systems. However, few studies have rigorously measured the different pathways of C loss from these systems over the long term. ARS researchers at St. Paul, Minnesota, made long-term (9-year) field-scale gas exchange measurements, measured soil C, and accounted for C export in dairy products. The results showed that annual application of dairy manure at recommended rates does not supply enough C to maintain soil C levels in fields where corn silage is annually removed. Inclusion of three years of alfalfa in the 9-year rotation reduced the C deficit, but still was insufficient to maintain soil C. This information highlights the need to develop more sustainable systems that can be implemented by dairy producers.

Review Publications
Deventer, M.J., Roman, T., Bogoev, I., Kolka, R.K., Erickson, M., Lee, X., Baker, J.M., Millet, D.B., Griffis, T.J. 2021. Biases in open-path carbon dioxide flux measurements: Roles of instrument surface heat exchange and analyzer temperature sensitivity. Agricultural and Forest Meteorology. 296. Article 108216. https://doi.org/10.1016/j.agrformet.2020.108216.
Griffis, T.J., Roman, D.T., Wood, J.D., Deventer, J.M., Fachin, L., Rengifo, J., del Castillo Torres, D., Lilleskov, E., Kolka, R.K., Chimner, R.A., del Aguila-Pasquel, J., Wayson, C., Hergoualc'h, K., Baker, J.M., Cadillo-Quiroz, H., Ricciuto, D.M. 2020. Hydrometeorological sensitivities of net ecosystem carbon dioxide and methane exchange of an Amazonian palm swamp peatland. Agricultural and Forest Meteorology. 295. Article 108167. https://doi.org/10.1016/j.agrformet.2020.108167.
Yu, Z., Griffis, T.J., Baker, J.M. 2021. Warming temperatures lead to reduced summer carbon sequestration in the U.S. Corn Belt. Communications Earth & Environment. 2. Article 53. https://doi.org/10.1038/s43247-021-00123-9.
Griffis, T.J., Baker, J.M. 2020. Nitrogen management and air quality in China. Nature Food. 1:597-598. https://doi.org/10.1038/s43016-020-00167-8.
Solhaug, E., Roy, R., Venterea, R.T., Carter, C. 2020. The role of alanine synthesis and nitrate-induced nitric oxide production during hypoxia stress in Cucurbita pepo nectaries. The Plant Journal. 105(3):580-599. https://doi.org/10.1111/tpj.15055.
Souza, E., Rosen, C., Venterea, R.T. 2021. Co-application of DMPSA and NBPT with urea mitigates both nitrous oxide emissions and nitrate leaching during irrigated potato production. Environmental Pollution. 284. Article 117124. https://doi.org/10.1016/j.envpol.2021.117124.
Venterea, R.T., Clough, T.J., Coulter, J.A., Souza, E.F., Breuillin-Sessoms, F., Spokas, K.A., Sadowsky, M.J., Gupta, S.K., Bronson, K.F. 2021. Temperature alters dicyandiamide (DCD) efficacy for multiple reactive nitrogen species in urea-amended soils: Experiments and modeling. Soil Biology and Biochemistry. 160. Article 108341. https://doi.org/10.1016/j.soilbio.2021.108341.
Gamble, J.D., Feyereisen, G.W., Griffis, T.J., Wente, C.D., Baker, J.M. 2021. Long-term ecosystem carbon losses from silage maize-based forage cropping systems. Agricultural and Forest Meteorology. 306. Article 108438. https://doi.org/10.1016/j.agrformet.2021.108438.
Schaefer, A., Werning, K., Hoover, N., Tschirner, U., Feyereisen, G.W., Moorman, T.B., Howe, A.C., Soupir, M.L. 2021. Impact of flow on woodchip properties and subsidence in denitrifying bioreactors. Agrosystems, Geosciences & Environment. 4(1). Article e20149. https://doi.org/10.1002/agg2.20149.
Feyereisen, G.W., Spokas, K.A., Strock, J.S., Mulla, D.J., Ranaivoson, A.Z., Coulter, J.A. 2020. Nitrate removal and nitrous oxide production from upflow and downflow column woodchip bioreactors. Agricultural and Environmental Letters. 5(1). Article e20024. https://doi.org/10.1002/ael2.20024.
Christianson, L.E., Cooke, R.A., Hay, C.H., Helmers, M.J., Feyereisen, G.W., Ranaivoson, A.Z., McMaine, J.T., McDaniel, R., Rosen, T.R., Pluer, W.T., Schipper, L.A., Dougherty, H., Robinson, R.J., Layden, I.A., Irvine-Brown, S.M., Manca, F., Dhaese, K., Nelissen, V., Von Ahnen, M. 2021. Effectiveness of denitrifying bioreactors on water pollutant reduction from agricultural areas. Transactions of the ASABE. 64(2):641-658. https://doi.org/10.13031/trans.14011.
Gamiz, B., Lopez-Cabeza, R., Velarde, P., Spokas, K.A., Cox, L. 2020. Biochar changes the bioavailability and bioefficacy of the allelochemical coumarin in agricultural soils. Pest Management Science. 77(2):834-843. https://doi.org/10.1002/ps.6086.
Munira, S., Dynes, J.J., Islam, M., Khan, F., Adesanya, T., Regier, T.Z., Spokas, K.A., Farenhorst, A. 2021. Relative proportions of organic carbon functional groups in biochars as influenced by spectral data collection and processing. Chemosphere. 283. Article 131023. https://doi.org/10.1016/j.chemosphere.2021.131023.
Ginakes, P., Grossman, J., Baker, J.M., Sooksa-nguan, T. 2020. Living mulch management spatially localizes nutrient cycling in organic corn production. Agriculture. 10(6). Article 243. https://doi.org/10.3390/agriculture10060243.
Alexander, J., Spackman, J., Wilson, M., Fernandez, F., Venterea, R.T. 2021. Capture efficiency of four chamber designs for measuring ammonia emissions. Agrosystems, Geosciences & Environment. 4(3). Article e20199. https://doi.org/10.1002/agg2.20199.
Bronson, K.F., Hunsaker, D.J., El-Shikha, D., Rockholt, S.M., Williams, C.F., Rasutis, D., Soratan, K., Venterea, R.T. 2021. Nitrous oxide emissions, N uptake, biomass, and rubber yield in N-fertilized, surface-irrigated guayule. Industrial Crops and Products. 167. Article 113561. https://doi.org/10.1016/j.indcrop.2021.113561.
Trippe, K.M., Manning, V., Reardon, C.L., Klein, A.M., Weidman, C.S., Ducey, T.F., Novak, J.M., Watts, D.W., Rushmiller, H.C., Spokas, K.A., Ippolito, J.A., Johnson, M.G. 2021. Phytostabilization of acidic mine tailings with biochar, biosolids, lime, and locally-sourced microbial inoculum: Do amendment mixtures influence plant growth, tailing chemistry, and microbial composition? Applied Soil Ecology. 165. Article 103962. https://doi.org/10.1016/j.apsoil.2021.103962.
Ducey, T.F., Novak, J.M., Sigua, G.C., Ippolito, J.A., Rushmiller, H.C., Watts, D.W., Trippe, K.M., Spokas, K.A., Stone, K.C., Johnson, M.G. 2021. Microbial response to designer biochar and compost treatments for mining impacted soils. Biochar. 3:299-314. https://doi.org/10.1007/s42773-021-00093-3.
Ippolito, J.A., Cui, L., Kammann, C., Wrage-Monnig, N., Estavillo, J.M., Fuertes-Mendizabal, T., Cayuela, M., Sigua, G.C., Novak, J.M., Spokas, K.A., Borchard, N. 2020. Feedstock choice, pyrolysis temperature and type influence biochar characteristics: a comprehensive meta-data analysis review. Biochar. 2:421-438. https://doi.org/10.1007/s42773-020-00067-x.
Rotz, C.A., Stout, R.C., Leytem, A.B., Feyereisen, G.W., Waldrip, H., Thoma, G., Holly, M., Bjorneberg, D.L., Baker, J.M., Vadas, P.A., Kleinman, P.J. 2021. Environmental assessment of United States dairy farms. Journal of Cleaner Production. 315. Article 128153. https://doi.org/10.1016/j.jclepro.2021.128153.
Gurung, R., Ogle, S., Breidt, J., Parton, W., Del Grosso, S.J., Zhang, T., Hartman, M., Williams, S., Venterea, R.T. 2021. Modeling nitrous oxide mitigation potential of enhanced efficiency nitrogen fertilizers from agricultural systems. Science of the Total Environment. 801. Article e149342. https://doi.org/10.1016/j.scitotenv.2021.149342.