FATES OF SOIL CARBON AND NITROGEN IN AGRICULTURAL SYSTEMS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: REVISED
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1020049
• Project No.: PEN04710
• Project Start Date: Jul 1, 2019
• Project End Date: Jun 30, 2024

Project Director
Kemanian, AR, R.

Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
208 MUELLER LABORATORY
UNIVERSITY PARK,PA 16802

Performing Department
Plant Science

Non Technical Summary
Agriculture produces the largest human footprint in the biosphere. Balancing an economically viable and environmentally sustainable agriculture is a grand challenge for our society in the 21st century (Robertson and Swinton, 2005; Hunter et al., 2015). This is so because, despite steady improvements in agricultural technology as well as an increased public awareness about the risks of environmental pollution, preventing nutrient losses and other downstream effects from high-input and high-output agricultural systems is challenging. This is especially true for nitrogen (N) and carbon (C).Our project will address these knowledge gaps. Our rationale for studying C and N in this project is that their biogeochemistry in the soil-microbiome-plant system is tightly coupled. Understanding whether C and N will be retained in soil and all the cascading processes that determine their release into water or the atmosphere requires an interdisciplinary approach that considers agricultural management, soil microbial communities, plant growth, and many other factors. Linking laboratory, field and in silico (modeling) experiments can accelerate progress towards a better understanding and management of the coupled C and N cycles. This project brings together a soil microbiologist (Bruns), a soil biogeochemist (Kaye), and an agroecologist and modeler (Kemanian) to examine the interacting factors that control soil C and N cycling in agroecosystems. Losses of C and N to air and water are environmentally and economically damaging. We expect that this project will improve N management and C storage, providing the knowledge, tools and justification for productive and environmentally judicious management of agricultural systems.While past projects have improved our understanding of which cover crops or mixtures of cover crops can prevent N leaching while still providing N for subsequent cash crops, key knowledge gaps remain, among them understanding the interaction between cover crop and manure that determine C and N stabilization or release. Our projects have shown that while silage production with polycultures is feasible, its integration in systems and its effects on the soil C and N economy remain largely unexplored. Our experiments on cover cropping, cropping systems and biomass crops will enable exploring the expression of cumulative, long-term trends. On the modeling front, these experiments become invaluable data sources for ground-truthing C and N cycling modeling. Our project will address these knowledge gaps.

Animal Health Component

0%

Research Effort Categories

Basic

35%

Applied

35%

Developmental

30%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	0110	1070	60%
205	1599	1070	30%
112	0210	2020	10%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 205 - Plant Management Systems; 112 - Watershed Protection and Management;

Subject Of Investigation
0110 - Soil; 1599 - Grain crops, general/other; 0210 - Water resources;

Field Of Science
2020 - Engineering; 1070 - Ecology;

Keywords

soil carbon

soil nitrogen

cover crops

biomass crops

denitrification

nitrous oxide

agroecosystems modeling

Goals / Objectives
Agriculture produces the largest human footprint in the biosphere. Balancing an economically viable and environmentally sustainable agriculture is a grand challenge for our society in the 21st century (Robertson and Swinton, 2005; Hunter et al., 2015). This is so because, despite steady improvements in agricultural technology as well as an increased public awareness about the risks of environmental pollution, preventing nutrient losses and other downstream effects from high-input and high-output agricultural systems is challenging. This is especially true for nitrogen (N) and carbon (C). Agriculture is the most important driver of changes in the global N cycle through large inputs of reactive N via inorganic N fertilizers and legume cultivation (Galloway and Cowling 2002). These changes are important locally, regionally and globally. In the mid-Atlantic region, losses of N through leaching contribute to water quality pollution of streams and the Chesapeake Bay. Losses of gaseous ammonia from Pennsylvania's agricultural ecosystems affect downwind forests and aquatic ecosystems. Losses of nitrous oxide increase its concentration in the atmosphere contributing to both warming of the atmosphere and depletion of the ozone layer.Agriculture also plays a role in local, regional and global carbon cycling. With climate change progressing at an accelerated pace, society is increasingly looking to agricultural ecosystems to store C in soils and to grow bioenergy crops with low global warming potential (Griscom et al., 2017). However, our fundamental understanding of soil C cycling is changing rapidly. Non-linear processes like priming and carbon saturation, processes considered possible and interesting not long ago, are becoming an integral part of our conceptual understanding of soil C and N cycling (Mazzilli et al., 2014; Perveen et al., 2019; Pravia et al., 2019). No-till may not sequester as much soil C as expected (Powlson et al., 2014), but cover crops may convey substantial climate benefits (Kaye and Quemada, 2017). Significant expansion of biomass crops, especially on marginal lands, could also affect the C balance of terrestrial ecosystems. In the Northeast, woody plants, annual small grain cover crops, and perennial grasses are all being considered as potential energy crops. The productivity and lifecycle global warming potential of these systems are still poorly constrained.Better understanding of novel processes in the soil-microbiome-plant system can improve agricultural productivity, resilience and sustainability (Bhowmik et al., 2017). One example is the potential to use cyanobacteria in temperate agricultural systems (Peng and Bruns, 2019a). Of the three recognized types of N-fixing soil bacteria, symbiotic, associative, and free-living, free-living cyanobacteria have not been considered a significant source of renewable N in U.S. agriculture, which does not come as a surprise given the large amounts of N input through fertilizers (Unkovich and Baldock, 2008). Worldwide, however, less than half of applied N in agriculture is assimilated into crop biomass (Cameron et al., 2013). Although free-living cyanobacteria have been reported to contribute 5-40 kg N per hectare annually (Unkovich and Baldock, 2008), they are not considered significant renewable N sources in temperate cropping systems (Peng and Bruns, 2019b). It remains to be seen if an increasing concentration of carbon dioxide in the atmosphere could enhance not only legume growth but also photosynthetic di-nitrogen fixers on moist, temperate soils, an important knowledge gap.Management practices that increase soil organic matter (e.g., manure/compost additions, perennials in crop rotations, cover cropping) are known to increase the biomass and activity of both soil bacterial and fungal communities (Johnston et al., 2009). An important knowledge gap is how these practices affect specific bacterial processes that could aid in soil N retention and N use efficiency. Such processes include more tightly coupled N mineralization and reuptake by bacteria, conversion of mobile nitrate to less mobile ammonium, and conversion of the potent greenhouse gas N2O to inert N2 gas. Little is known about the differential impact of reduced tillage on saprotrophic fungi and mycorrhizae and their roles in carbon and nitrogen cycling. Recent advances in microbiome analysis tools will help us acquire knowledge of soil microbial taxa and their functions (Bell et al., 2019).Our rationale for studying C and N in the same project is that their biogeochemistry in the soil-microbiome-plant system is tightly coupled. Understanding whether C and N will be retained in soil and all the cascading processes that determine their release into water or the atmosphere requires an interdisciplinary approach that considers agricultural management, soil microbial communities, plant growth, and many other factors. Linking laboratory, field and in silico (modeling) experiments can accelerate progress towards a better understanding and management of the coupled C and N cycles. This project brings together a soil microbiologist (Bruns), a soil biogeochemist (Kaye), and an agroecologist and modeler (Kemanian) to examine the interacting factors that control soil C and N cycling in agroecosystems. Losses of C and N to air and water are environmentally and economically damaging. We expect that this project will improve N management and C storage, providing the knowledge, tools and justification for productive and environmentally judicious management of agricultural systems.Over the next five years we will evaluate agricultural systems C and N cycling and retention from soil and field to landscape scales. The systems to be considered encompass organic and conventional systems, with emphases on the influence on C and N cycling and the soil microbiome of cover crops, biomass and energy crops, and silage polycultures. We will also improve simulation models and decision support tools that couple C and N to provide new tools for N management and productivity evaluation at field and watershed scales. Our specific objectives are:1) Cover crops (Kaye, Kemanian, Montes): Evaluate how cover crops and the diversity of planted cover crops contribute to multiple ecosystem services related to the C and N cycles. Ecosystem services to be evaluated include reducing N leaching losses, potential for cover crop N fixation to supply N to cash crops, reducing soil erosion, increasing soil C storage, and control of nitrous oxide emission. We will explore the regulation of these services by the C:N ratio of pure or mixed cover crops stands as well as innovative tillage.2) Biomass and energy crops (Kemanian, Montes): Measure and model C and N storage in shrub willow pure and polyculture stands and in warm season grasses.3) Simulation models and decision tools (Kemanian, Kaye, Montes, Bruns): Improve simulation models that couple C and N to simulate ecosystem dynamics and provide new tools for N fertility management. Expand this tool to landscape through spatially distribute modeling using the Cycles and PIHM models.4) Soil microbiome (Bruns, Montes): Overarching goal is to identify manure and soil management practices that help reduce agriculture's contributions to greenhouse gases, particularly nitrous oxide. The specific objectives are: i) Measure bacterial groups and labile C substrates in manures from dairies of varying size and manure handling systems; ii) measure greenhouse gases and temporal and spatial changes in NA and denitrification in no-till soils; and iii) conduct soil mesocosm studies to determine relationships between substrates, physicochemical conditions, microbial processes, and greenhouse gases to understand conditions favoring NA over denitrification.

Project Methods
1) Cover Crops: We will continue working on the existing Cover Crops Cocktail experiment at the Russell E. Larson Experimental farm, as well as in new experiments at the experiment station and on-farm. Current experiments contrast monoculture cover crops with mixtures that include up to 9 species of cover crops. Our hypothesis is that polycultures provide more ecosystem services than cover crop monocultures. Emphases will be given to innovative practices that balance ecosystem services trade-offs (timing of cover crop termination as a function of the mixture, smart tillage for weed and nutrient cycling) and to monitoring parsimonious or episodic processes that are methodologically challenging to measure, such as leaching below the plow layer and burst of nitrous oxide emission. We will quantify the cover crop N supply to cash crops, monitor soil inorganic N biweekly following cover crop termination as well as the yield and nutrient concentrations of cash crops. To monitor N leaching, we bury ion exchange resins below the prominent rooting zone of plants and monitor N leaching through the soil profile. In a subset of our plots we also measure N leaching with bucket lysimeters. Nitrous oxide is monitored on three contrasting treatments (a grass cover crop, a legume cover crop, and a three-way mixture) using the static chamber method. Finally, we will continue using our protocol for tracking changes in soil organic matter, particulate organic matter, and total soil C to detect impacts of cover crops and other practices on soil C pools.2) Biomass and Energy Crops: The Penn State's Rockview shrub willow experiment is being monitored using two eddy covariance systems that measure carbon dioxide and water exchange at 30 minutes intervals. The field has an area of 35 acres and the eddy covariance systems are located downwind with a fetch from the edge of the field to instruments of more than 900 ft. The C and N stored in plant and remove at harvest will be measured and compared with eddy covariance system to estimate with accuracy both the C storage and water use. An additional experiment recently completed provided substantial information on N dynamics using stable isotopes. This information will be analyzed and summarized through this project.3) Simulation Models: We continue to develop Cycles and further develop the spatially distributed model C-PIHM. Cycles is a biogeochemical model with coupled C and N cycles that is being expanded to include phosphorous. We will also downscale from the current Cycles scale to the dynamics of the plow layer in organic or any tilled system to simulated microsite conditions that we surmise will enable modeling nitrous oxide emissions with more accuracy. Process-based models are used to simulate the complex interactions among plant growth and yield, C and N cycling, environmental conditions, soil properties, and management practices (Williams, 1990; McCown et al., 1996, Meki et al., 2013), but are still fairly weak at modeling specific episodes of nitrous oxide emission. While decision support tools have been in vogue for decades, documenting its use has been challenging. We will deploy a newly developed online tool (prototype at: https://www.cycles-model.psu.edu/Cycles/CyclesModel.html) that will allow users unrestricted access to an agroecosystem decision tool.4) Soil Microbiome: We hypothesize that nitrite ammonification and denitrification occur to a significant extent in soils managed using no-till practices and receiving labile C amendments as cover crop biomass and manure biomass. The role of denitrification and nitrite ammonification in till and no-till systems, and the interaction with manure is largely unknow. Our cropping system experiments as well as those of our collaborators provide ideal grounds for testing this hypothesis.The objectives and activities of this project reflect overlapping interests and shared experiments. The large field experiments managed by Kaye and Kemanian as well as the laboratory experiments in controlled conditions supervised by Bruns produce a fertile environment for collaborative work and graduate students' projects. The proposed project complements Project 4425, "Developing Sustainable Cropping Systems for the Northeast," whose project description points out that "a combination of [agronomic] practices can have cumulative effects over time." Such cumulative effects include and are a response to the amounts, types, and turnover rates of soil C and N compounds, which are the focus of our proposal.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:The target audiences for our work includes farmer advisory panels for the Northeast Sustainable Agricultural Research and Education (NESARE) Dairy Cropping System experiment (transitioned to a project within the Long-Term Agricultural Research program) and the Long term Cover Crop Cocktail Experiment farmer-cooperators participating in USDA NIFA research conducted by graduate students and postdocs; colleagues in academia and state and federal agencies, as well as parties interested in technology and policy including extension, non-governmental agencies, producers and state and federal action agencies. Changes/Problems:Estelle Couradeau, Assistant Professor, joined the Dept of Ecosystem Science at Penn State in January, 2020. She agreed to join this proposal and contribute her expertise in soil microbiome analysis. What opportunities for training and professional development has the project provided?Currently fourteen graduate students are being trained by faculty participating in this project. Two graduate students have received Northeast Sustainable Agricultural Research and Education Fellowships and two have received AFRI Predoctoral Fellowships during this period. Several undergraduate students have also participated in research support as wage-payroll assistants. How have the results been disseminated to communities of interest?Results of research have been disseminated through peer-reviewed publications, webinars, field days, professional scientific meetings, and presentations at the November 2019 TriSocieties Meetings in San Antonio, TX.In August, 2019, faculty and graduate students presented to audiences at the NESARE Dairy Cropping Systems field day and tour, and the Advisory Panel heard additional presentations in December 2019. In November, 2019, a Watershed Specialist meeting was held in State College on dairies and cover cropping. What do you plan to do during the next reporting period to accomplish the goals?Simulation models and decision tools will continue to be modified and tested. For the CC Tool, future analyses will determine if the 100% fertilizer recovery efficiency assumed by the CC Tool's recommendation equation can be refined to increase accuracy of recommendations. Currently soil health indicator data from the Dairy Cropping Systems experiment is being compiled for analysis, synthesis, and publication.

Impacts
What was accomplished under these goals? This year we evaluated biogeochemical cycling in agricultural and bioenergy systems from soil to field to landscape scales. The systems encompass organic, rotational, and conventional systems, with emphases on the influence on C and N cycling and the soil microbiome of cover crops, biomass and energy crops, and silage polycultures. We made progress in improving simulation models and decision support tools that couple C and N to provide new tools for N management and productivity evaluation at field and watershed scales. Accomplishments under the four goals listed above are as follows: Goal 1: Our research has generated knowledge on how cover crops contribute to multiple ecosystem services related to the C and N cycles, including reducing N leaching losses, potential for cover crop N fixation to supply N to cash crops, reducing soil erosion, increasing soil C storage, and control of nitrous oxide emission. Several studies focused on the regulation of these services by the C:N ratios of pure or mixed cover crops stands as well as by use of innovative tillage practices. (Kaye) Goal 2: Several studies assessed effects of management affecting soil conditions, yields, and off-site nutrient losses. In Ernst et al paper, we showed that no-till practices preserve soil conditions that do not limit grain yield when it includes either pastures or maize or sorghum in the rotation. When soybean replaces the two summer cereals, soil properties gradually degrade as measured by the wheat yield response (we used wheat yield as the biological indicator of the soil conditions) and a parallel reduction in the soil maximum infiltration rate. This experiment was 20 years old when we did the experiment comparing the effect on wheat. In the Stefani-Fae paper, our study suggested that manure applications improve soil physical properties, using soybean yield as indicator of better soil condition. While this study cannot be used to conclude that improved soil condition was due to manure C and N addition, it offers indirect evidence that manure application resulted in more favorable water infiltration and retention, as measured by ksat differences using an in situ infiltrometer. The near record soybean yields were thus best explained by differences in ksat. Interestingly, other soil quality measures failed to represent soil productivity with fidelity. Agricultural impacts on lake water quality were reported in the Stachelek paper, which analyzed hundreds of lakes and shows that the impact of agriculture on lake water quality are highly dependent on watershed attributes for nitrogen and on lake attributes for phosphorus. Furthermore, the effects vary by watershed, and interestingly lakes in some watersheds in Iowa seem to be more sensitive to land use. Lakes in watershed with streams with less row crops seem to have better water quality than those with cropped riparian areas, but it is not clear if the effect is a general increase in cropping area or the locations of the cropped area itself. (Kemanian, Montes) Goal 3: The simulation model Cycles, coupled with the hydrology model PIHM, has been set up for distributed modeling in subwatershed of the larger Mahantango creek watershed in east-central Pennsylvania. Cycles simulates the biogeochemistry of N and C. The actual management practices used by producers, including cover crops and manure applications were incorporated in the input files. Preliminary simulations were conducted that show distributed nitrogen fluxes across the watershed. Spring stream flow is slightly overestimated, but overall the water balance has been calibrated correctly by altering the depth of the macropores and depth to bedrock (which alters the volume of water stored in the watershed groundwater). Plot level simulations in our experiments were used to parameterize the model and organic matter mineralization rates are in line with those expected in the region thermal and hydric regime. Comparison of simulated and measured N concentration and water fluxes in the stream are now possible in this sample watershed. (Kemanian, Montes) Goal 4: Microbiome research has focused on the effects of tillage practices, crop type and soil conditions on nitrate-ammonifying bacterial populations, which can affect N loss from soil by promoting longer soil N retention as ammonium instead of losses as N2 and N2O. Model results indicate a significant interaction between tillage treatment (no-till vs. moldboard plow) and type of sample (p = 0.0238), and between type of sample (rhizosphere or bulk) and sample date (p < 0.0001). Analysis of pairwise comparisons between tillage type revealed a significantly higher potential for nitrate ammonification in the no-till bulk soils compared to the plowed bulk soils. Analysis comparing samples taken from corn and soybean indicated a higher potential for nitrate ammonification in the corn rhizosphere and bulk soils compared to the soybean rhizosphere and bulk soils. Finally, results analyzed from the 2018 Dairy Cropping Systems project indicated that although nitrate ammonification potential in fall-terminated alfalfa/orchardgrass was higher in the following spring than spring-terminated alfalfa/orchardgrass, N2O emissions were not significantly different. (Bruns)

Publications

• Type: Journal Articles Status: Accepted Year Published: 2020 Citation: White, C.M., D.M. Finney, A.R. Kemanian, J.P. Kaye. 2020. Modeling the contributions of nitrogen mineralization to yield of corn. Agronomy Journal, accepted.
• Type: Journal Articles Status: Accepted Year Published: 2020 Citation: McConnell, CA, JP Kaye, and AR Kemanian. 2020. Review and Synthesis: Ironing out wrinkles in the soil phosphorus cycling paradigm. Biogeosciences https://doi.org/10.5194/bg-2020-130
• Type: Journal Articles Status: Accepted Year Published: 2020 Citation: Dove, N., K. Arogyaswamy, S. Billings, J. Botthoff, C. Carey, C. Cisco, J. DeForest, D. Fairbanks, N. Fierer, R. Gallery, J. Kaye, K. Lohse, M. Maltz, E. Mayorga, J. Pett-Ridge, W. Yang, S. Hart, E. Aronson. 2020. Continental-scale patterns of extracellular enzyme activity in the subsoil: an overlooked reservoir of microbial activity. Environmental Research Letters. In press.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Amisli, J.P. and J.P. Kaye. 2020. Root traits of cover crops and carbon inputs in an organic grain rotation. Renewable Agriculture and Food Systems. 1-10. https://doi.org/10.1017/S1742170520000216
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Baraibar, B. EG Murrell, BA Bradley, ME Barbercheck, DA Mortensen, JP Kaye, CM White. 2020. Cover crop mixture expression is influenced by nitrogen availability and growing degree days. PLOS ONE 15(7): e0235868. https://doi.org/10.1371/journal.pone.0235868
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Wallace, J., S. Isbell, R. Hoover, M. Barbercheck, J. Kaye, and W. Curran. 2020. Drill and broadcast establishment methods influence interseeded cover crop performance in organic corn. Renewable Agriculture and Food Systems. https://doi.org/10.1017/S174217052000006X
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Smeglin, Y, K Davis, Y Shi, D Eissenstat, J Kaye, and M Kaye. 2020. Observing and simulating spatial variations of forest carbon stocks in complex terrain. Journal of Geophysical Research: Biogeosciences 125, e2019JG005160. https://doi.org/10.1029/2019JG005160.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Cloutier, M.L., Chatterjee, D., Elango, D., Cui, J., Bruns, M.A. Chopra, S. 2020. Sorghum root flavonoid chemistry, cultivar, and frost stress effects on rhizosphere bacteria and fungi. Phytobiomes Journal 2020 doi: 10.1094/PBIOMES-01-20-0013-FI
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Cloutier, M.L., Murrell, E., Kaye, J., Barbercheck, M., Finney, D., Gonzalez, I.G., Bruns, M.A. 2020. Fungal community shifts in soils with varied cover crop treatments and edaphic properties. Scientific Reports doi: 10.1038/s41598-020-63173-7
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Castano-Sanchez, J., Rotz, A., Karsten, H. D., & Kemanian, A. R. 2020. Elevated atmospheric carbon dioxide effects on dairy crops in the Northeast US: A comparison of model predictions and observed data. Agricultural and Forest Meteorology, 291.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Ernst, O. R., Kemanian, A. R., Siri-Prieto, G., Mazzilli, S., & Dogliotti, S. 2020. The dos and don'ts of no-till continuous cropping: evidence from wheat yield and nitrogen use efficiency. Field Crops Research 257, 107934.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Stockle, C. O., & Kemanian, A. R. 2020. Can crop models identify critical gaps in genetics, environment, and management interactions? Frontiers in Plant Science, 11.
• Type: Journal Articles Status: Accepted Year Published: 2020 Citation: Stachelek, J., Wang, W., Carey, C. C., Kemanian, A. R., Cobourn, K. M., Wagner, T., Weathers, K. C., & Soranno, P. 2020. Agricultural land-use and lake water quality relationships differ when considering predictor granularity at macroscales Ecological Applications. e02187.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Stefani Fae, G. O., Kemanian, A. R. (Co-Author), Roth, G. W., White, C., & Watson, J. E. 2020. Soybean yield in relation to environmental and soil properties. European Journal of Agronomy, 118.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Hoffman, A. L., Kemanian, A. R., & Forest, C. E. 2020. The response of maize, sorghum, and soybean yield to growing-phase climate revealed with machine learning. Environmental Research Letters, 15.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Kaye, JP, SL Brantley, J Zan Williams, et al. 2019. Ideas and perspectives: Proposed best practices for collaboration at cross-disciplinary observatories. Biogeosciences 16: 4661-4669.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhi, W., L. Li, W. Dong, W. Brown, J. Kaye, C. Steefel, and K.H. Williams. 2019. Distinct source water chemistry shapes contrasting concentration-discharge patterns. Water Resources Research, 55:42334251. https://doi.org/10.1029/2018WR024257
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Hodges, C., H. Kim, S. L. Brantley, J. Kaye. 2019. Soil CO2 and O2 concentrations illuminate the relative importance of weathering and respiration to seasonal soil gas fluctuations. 2019. Soil Science Society of America Journal. 83:11671180. doi: 10.2136/sssaj2019.02.0049
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Brewer T.E., E.L. Aronson, K. Arogyaswamy, S.A. Billings, J.K. Botthoff, A.N. Campbell, N.C. Dove, D. Fairbanks, R.E. Gallery, S.C. Hart, J. Kaye, G. King, G. Logan, K.A. Lohse, M.R. Maltz, E. Mayorga, C. ONeill, S.M. Owens, A. Packman, J. Pett-Ridge, A.F. Plante, D.D. Richter, W.L. Silver, W.H. Yang, N. Fierer. 2019. Ecological and genomic attributes of novel bacterial taxa that thrive in subsurface soil horizons. mBio 10:e01318-19. https://doi.org/10.1128/mBio.01318-19.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Kizewski, F.R., J.P. Kaye, and C.E. Mart�nez. 2019. Nitrate transformation and immobilization in particulate organic matter incubations: Influence of redox, iron and (a)biotic conditions. PLoS ONE 14 (7): e0218752. https://doi.org/10.1371/journal. pone.0218752
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Hunter, M., C.M. White, J.P. Kaye, and A.R. Kemanian. 2019. Ground-truthing a recent report of cover-crop-induced winter warming. Agricultural and Environmental Letters. doi: 10.2134/ael2019.03.0007
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Kaye, J.P, D. Finney, C. White, B. Bradley, M. Schipanski, M. Alonso-Ayuso, M. Hunter, M. Burgess, and C. Mejia. 2019. Managing nitrogen through cover crop species selection in the U.S. mid-Atlantic. Plos One 14(4): e0215448. https://doi.org/10.1371/journal.pone.0215448
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Sullivan, P. L., Y. Godd�ris, Y. Shi, X. Gu, J. Schott, E.A. Hasenmueller, J.P. Kaye, C. Duffy, H. Lin, and S. Brantley. 2019. Exploring the effect of aspect to inform future earthcasts of climate-driven changes in weathering of shale. Journal of Geophysical Research: Earth Surface, 124. https:// doi.org/10.1029/2017JF004556
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Hunter, M.C., Schipanski, M.E., Burgess, M.H., LaChance, J.C., Bradley, B.A., Barbercheck, M.E., Kaye, J.P., and D.A. Mortensen. 2019. Cover crop mixture effects on maize, soybean, and wheat yield in rotation. Agricultural and Environmental Letters 4:180051. doi:10.2134/ael2018.10.0051
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Murrell E.G., Ray S., Lemmon M.E., Luthe D.S., Kaye J.P. 2019. Cover crop species affect mycorrhizae-mediated nutrient uptake and pest resistance in maize. Renewable Agriculture and Food Systems. https://doi.org/10.1017/S1742170519000061
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Hoagland, B., C. Schmidt, T. Russo, R. Adams, J. Kaye. 2019. Controls on nitrogen transformation rates on restored floodplains along the Cosumnes River, California. Science of the Total Environment 649: 979994
• Type: Book Chapters Status: Published Year Published: 2020 Citation: Bruns, M.A. 2020. Bacteria and Archaea, in Principles and Applications of Soil Microbiology, D. Zuberer, T. Gentry, and J. Fuhrmann, eds. Elsevier, New York.

Progress 07/01/19 to 09/30/19

Outputs
Target Audience:The target audiences are (1) academic, (2) producer organization and (3) state and federal policy makers. Academic audiences are reached through participation in scientific conferences, review panels and scientific publications. Producer audiences are reached through field days associated to externally funded projects, focus groups meetings and projects advisory boards that include producers and that are our liaison with a larger network of producers. Among the commodity groups are organic producers, the soybean board, and others. And among the policy oriented groups are the Chesapeake Bay Commission and the Pennsylvania Department of Agriculture. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Students continue improving the application of machine learning techniques. Students and postdocs have learned state-of-the-art techniques for monitoring willow leaf beetle and japanese beetle populations, and to monitor large fields using aerial unmanned vehicles. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?Experiments are undergoing to understand the production, further reduction or emission of nitrous oxide in soils subject to precision layering of manure and cover crops residues. Research on the interaction between nitrogen supply by cover crops and demand by cash crops, as well as the impact of cover crop diversity on soil health and microbiome diversity continues. The development of the Cycles modeling system continues. The overall goal is to increase the fidelity of the modeling systems. Multiple templates representing typical producer rotations have been made available. Satellite based yield data is being incorporated to represent both the actual rotation in each field on the nation (first targets are Pennsylvania and Iowa) and to account for field variation.

Impacts
What was accomplished under these goals? This reports covers only 3 months of activities and is therefore brief. Cover crops research is focusing on the interaction of the plant-microbiome soil complex. The large cover crops cocktail experiment has been adapted to host research in this area. Preliminary trials let us design tillage practices for precision layering of cover crops residues and manure in the plow layer. Bioenergy crops: we established a 35-ac fertilization experiment, with half of the area fertilizer with nitrogen and phosphorous after harvest of shrub willow. Monitoring has focused on herbivory by willow leaf beetle, which seems to reduce leaf area and in practical term reduce carbon input to the system. We documented stark differences among cultivars on the tolerance to willlow leaf beetle. We also completed training to start monitoring willow using unmanned aerial vehicles. We successfully established a trial to monitor shrub willow tolerance to continuous irrigation at the Penn State living filter. In addition to the work on carbon and nitrogen, we completed a review of the role of phosphorous in co-regulating organic carbon and nitrogen cycle.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Garijo, D., Khider, D., Ratnakar, V., Gil, Y., Deelman, E., da Silva, R.F., Knoblock, C., Chiang, Y.Y., Pham, M., Pujara, J. and Vu, B., 2019, March. An intelligent interface for integrating climate, hydrology, agriculture, and socioeconomic models. In Proceedings of the 24th International Conference on Intelligent User Interfaces: Companion (pp. 111-112). ACM.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: White, C.M., Bradley, B., Finney, D.M. and Kaye, J.P., 2019. Predicting Cover Crop Nitrogen Content with a Handheld Normalized Difference Vegetation Index Meter. Agricultural & Environmental Letters, 4(1).
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Peng, X. and Bruns, M.A., 2019. Development of a nitrogen-fixing cyanobacterial consortium for surface stabilization of agricultural soils. Journal of Applied Phycology, 31(2), pp.1047-1056.
• Type: Journal Articles Status: Accepted Year Published: 2019 Citation: Cloutier, M.C.,* Bhowmik, A., Bell, T.H., Bruns, M.A. 2019. Innovative technologies to improve understanding of microbial N dynamics in agricultural soils. Agricultural and Environmental Letters, in press.
• Type: Other Status: Published Year Published: 2019 Citation: Bruns, M.A. 2019. Making the Most of Microbes for Soil Restoration and Function. Research Outreach 108:98-101, https://researchoutreach.org/articles/making-the-most-of-microbes-for-soil-restoration-and-function/
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Peng X.*, Bruns M.A. 2019. Cyanobacterial soil surface consortia mediate N cycle processes in agroecosystems. Frontiers in Environ Science Vol. 6: Article 156 (12 pages)
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Bell, T.H., Hockett, K.L., Alcala-Briseno, R.I., Barbercheck, M., Beattie, G.A., Bruns, M.A., Carlson, J.E., and 23 additional authors. 2019. Manipulating wild and tamed phytobiomes: challenges and opportunities. Phytobiomes: 3:3-12.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Chen, L.,** Hile, M.L., Fabian-Wheeler, E.E., Xu, Z., Bruns, M.A., Brown, V. 2018. Iron oxide to mitigate hydrogen sulfide gas release from gypsum-bedded dairy manure storages. Transactions of the ASABE 61:1101-1112.