Location: Soil and Water Management Research
2017 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
Objective 1a: A field experiment has been initiated at the University of Minnesota Research and Outreach Center in Rosemount, Minnesota. The objective is to determine optimal N rates for corn in a kura clover living mulch system, for both 1st and 2nd year corn following an established kura clover stand in two consecutive years (2017 and 2018). The experiment is a randomized complete block with four replications, with plots that are six rows (4.6 m) wide and 15.2 m long. Eight N management treatments will be used: a non-N-fertilized control; 40, 80, 120, 180, and 250 kg N ha-1 applied through split application of urea containing nitrification and urease inhibitors, where 40 kg N ha-1 is applied prior to planting and the remaining N is side dressed at the six-leaf corn stage; 120 kg N ha-1 of urea (without microbial inhibitors) applied using the aforementioned split-application method or in a single application prior to planting. Data collection from all plots will include aboveground yield and carbon and N contents of kura clover prior to tillage and at corn harvest in the tilled strips and in the non-tilled furrow, yield and N content of corn grain, cob, and stover at corn physiological maturity, and residual soil nitrate-N content following corn harvest. Agronomic N use efficiency and corn N recovery efficiency, revenue, cost of production, and economic net return will be calculated. A second part of the project will examine factors affecting the initial establishment of kura clover. A field has been identified for this research, and an experimental plan has been developed. This research is being partially funded by the Minnesota Corn Research and Promotion Council. University of Minnesota collaborators are, is collaborating and providing additional expertise.
Objective 1b: Eight soils types were collected from across Minnesota as originally planned. The first round of the microcosm experiments was completed, and the data were analyzed and published ahead of schedule in Soil Biology and Biochemistry. The results showed for the first time that the ratio of two microbial genes, amoA and nxrA, explained greater than 78% of the variance in cumulative nitrite and nitrous oxide production across all eight soils and five urea addition rates. The results also showed that abundances of the nxrA gene declined above critical urea addition rates, indicating a consistent pattern of suppression of Nitrobacter-associated nitrite-oxidizing bacteria due to ammonia toxicity. In contrast, abundances of the nxrB gene exhibited a broader range of responses indicating that Nitrospira-associated nitrite-oxidizing bacteria responded differently than Nitrobacter-associated nitrite-oxidizing bacteria. Soil DNA extracts from this experiment were also submitted for 16S rRNA sequencing. The sequencing results were analyzed in collaboration with the University of Minnesota’s Biotechnology Institute and a manuscript was submitted for publication. A second round of microcosm experiments was initiated. This experiment will examine three of the eight soil types, each amended with urea and incubated at four temperatures (10 o, 15 o, 23 o and 30o C), with and without the addition of the nitrification inhibitor dicycandiamide. The newly-designed laboratory system for simultaneously measuring ammonia, nitric oxide and nitrous oxide gas production will be used in this experiment, and the normal suite of chemical and gene measurements will also be made. Collaboration with ARS scientist in Beltsville, Maryland and his collaborator at the University of Maryland, who will investigate additional DNA sequences.
Objective 1c: Eight soil types from various sites across Minnesota were acquired, in coordination with activities under Objective 1b. Laboratory incubation experiments have been initiated. Soil screening experiments will be conducted to construct a volatile compound database based on initial observations during residue mineralization.
Objective 2a: The automated flux chamber system for semi-continuous measurement of greenhouse gas fluxes is being deployed in a newly established field experiment at the University of Minnesota Research facility in Saint Paul. The experiment will use a randomized complete block design to examine the effects of crop N uptake and applied nitrogen fertilizer on greenhouse gas emissions.
Objective 2b: During the reporting period, collaboration on nutrient leaching from a range of Minnesota agricultural soils has been developed in collaboration with the University of Minnesota. A test method to compare leaching losses of nitrogen and phosphorus has been developed and used to compare phosphorus losses from soils with soil test phosphorus levels ranging from high to low with initiation of leaching occurring at 0, 1, 3, and 7 days after application of a mineral P fertilizer. On a second round of tests, we are adding dairy manure as a P source and mineral N fertilizer to the mineral P fertilizer source so that both N and P leaching losses can be measured. The methodology varies in these respects from the written NP 212 plan: the soil columns are undisturbed rather than re-packed; soil depth is 15 cm rather than 30 cm; the fixed factors are soil type, initial soil test P, and timing of leaching event, rather than soil type, manure type, and manure rate; the tests were carried out under lab conditions. The soils were collected mostly from the same research locations in the NP 212 plan and include sandy loam, silt loam, clay loam, and clay textures. In addition, laboratory work has been completed to investigate the effect of temperature on nutrient release from dairy manure to water and on the effects of placement of dairy manure within a snowpack. A manuscript describing the results of this multi-ARS location study is in draft form.
Accomplishments
1. Microbial gene ratios explain nitrous oxide dynamics. Nitrous oxide gas emissions from soil represent an economic loss of applied nitrogen fertilizer and also have important effects in the atmosphere. It is well-known that the nitrite molecule is an important regulator of soil nitrous oxide production. However, the behavior of nitrite under varying soil conditions cannot be readily predicted or managed. In this study, we closely examined the behavior of nitrite, nitrous oxide and microbial genes that regulate the transformation of urea fertilizer in eight different agricultural soil types from across the state of Minnesota. The results showed for the first time that the ratio of two microbial genes, amoA and nxrA, explained greater than 78% of the variance in cumulative nitrite and nitrous oxide production across all eight soils and five urea addition rates. The relationships found in this study provide a basis for scientists and land managers to develop improved process-based predictive models and more effective management strategies for reducing nitrous oxide losses from agricultural soils.
2. Tile drainage and delayed fertilizer application reduce nitrous oxide fluxes. Nitrous oxide has increased in concentration in the atmosphere by more than 20% since 1750, due largely to the application of fertilizers and manures. To date, no studies have evaluated nitrous oxide emissions under different combinations of fertilizer application timing and soil drainage conditions for corn. In this study, ARS scientists in St. Paul, Minnesota collaborated with University of Minnesota faculty on a two-year field experiment that compared nitrous oxide emissions following single, pre-plant fertilizer application versus a double, split fertilizer application with and without tile drainage. The split application also used microbial inhibitors designed to reduce microbial transformations of applied nitrogen. Averaged across years, the undrained soil emitted 1.8 times more nitrous oxide than the tile drained soil, and the double, split application emitted 26% less nitrous oxide than the single, pre-plant application with no grain yield differences. These results provide scientists and land managers with potential strategies for reducing losses of nitrous oxide emissions from fertilized soils.
Review Publications
Fernandez, F., Venterea, R.T., Fabrizzi, K. 2016. Corn nitrogen management influences nitrous oxide emissions in drained and undrained soils. Journal of Environmental Quality. 45(6):1847-1855. doi:10.2134/jeq2016.06.0237.
Spokas, K.A., Watts, D.W., Lee, T., Weis, R.D., Novak, J.M., Feyereisen, G.W., Ippolito, J.A. 2016. Biomass or biochar – Which is better at improving hydraulic properties? Acta Horticulturae. 1146:235-242. doi: 10.17660/ActaHortic.2016.1146.31.
Laird, D.A., Novak, J.M., Collins, H.P., Ippolito, J.A., Karlen, D.L., Lentz, R.D., Sistani, K.R., Spokas, K.A., Van Pelt, R.S. 2016. Multi-year and multi-location soil quality and crop biomass yield responses to hardwood fast pyrolysis biochar. Geoderma. 289:46-53.
Gamiz, B., Cox, L., Hermosin, M., Spokas, K.A., Celis, R. 2017. Assessing the effect of organoclays and biochar on the fate of abscisic acid in soil. Journal of Agricultural and Food Chemistry. 65(1):29-38. doi:10.1021/acs.jafc.6b03668.
Spokas, K.A., Marques, J., La Scala, N., Nater, E. 2017. Black Earths (Terra Preta): Observations of wider occurrence from natural fire. Encyclopedia of Soil Science. 3:2312–2315. Available: https://doi.org/10.1081/E-ESS3-120052897.
Wood, J.D., Griffis, T.J., Baker, J.M., Frankenburg, C., Verma, M., Yuen, K. 2017. Multiscale analyses of solar-induced florescence and gross primary production. Geophysical Research Letters. 44(1):533-541. doi:10.1002/2016GL070775.
Hall, K., Spokas, K.A., Gamizn, B., Cox, L., Papiernik, S.K., Koskinen, W.C. 2017. Glyphosate sorption/desorption on biochars – Interactions of physical and chemical processes. Pest Management Science. Available: http://onlinelibrary.wiley.com/doi/10.1002/ps.4530/full.
Gamiz, B., Velardea, P., Spokas, K.A., Hermosin, M., Cox, L. 2017. Biochar soil additions impacts herbicide fate: Importance of application timing and feedstock species. Journal of Agricultural and Food Chemistry. 65(15):3109-3117. Available: http://pubs.acs.org/doi/abs/10.1021/acs.jafc.7b00458.
Owens, J., Clough, T., Laubach, J., Hunt, J., Venterea, R.T. 2017. Nitrous oxide fluxes and soil oxygen dynamics of soil treated with cow urine. Soil Science Society of America Journal. 81(2):289-298. doi:10.2136/sssaj2016.09.0277.
Mehmood, K., Chavez Garcia, E., Schirrmann, M., Ladd, B., Kammann, C., Wrage-Monnig, N., Siebe, C., Estavillo, J.M., Fuertes-Mendizabal, T., Cayuela, M., Sigua, G.C., Spokas, K.A., Cowie, A.L., Novak, J.M., Ippolito, J.A., Borchard, N. 2017. Biochar research activities and their relation to development and environmental quality: A meta-analysis. Agronomy for Sustainable Development. doi:10.1007/s13593-017-0430-1.
Kammann, C., Ippolito, J., Hagemann, N., Borchard, N., Cayuela, M., Estavillo, J., Fuertes-Mendizabal, T., Jeffery, S., Kern, J., Novak, J.M., Rasse, D., Saarnio, S., Schmidt, H., Spokas, K.A., Wrage-Monnig, N. 2017. Biochar as a tool to reduce the agricultural greenhouse-gas burden-knowns, unknowns, and future research needs. Journal of Environmental Engineering and Landscape Management. 25(02):114-139.
Breuillin-Sessoms, F., Venterea, R.T., Sadowsky, M., Coulter, J., Clough, T., Wang, P. 2017. Nitrification gene ratio and free ammonia explain nitrite and nitrous oxide production in urea-amended soils. Soil Biology and Biochemistry. 111(1):143-153. doi:10.1016/j.soilbio.2017.04.007.
Feyereisen, G.W., Christianson, L.E., Moorman, T.B., Venterea, R.T., Coulter, J.A. 2017. Plastic biofilm carrier after corn cobs reduces nitrate loading in laboratory denitrifying bioreactors. Journal of Environmental Quality. 46(4):915-920. doi:10.2134/jeq2017.02.0060.
Baker, J.M., Griffis, T.J. 2017. Atmospheric humidity. In: Hatfield, J.L., Sivakumar, M.V.K., Prueger, J.H., editors. Agroclimatology: Linking Agriculture to Climate. Madison, WI: ASA, CSSA, SSSA. p. 1-14 doi:10.2134/agronmonogr60.2015.0031.
