Research Project: Sustainable Small Farm and Organic Grass and Forage Production Systems for Livestock and Agroforestry

Location: Dale Bumpers Small Farms Research Center

2022 Annual Report

Objectives
Objective 1. Management systems for improved growth, handling and storage of harvested biomass for optimized quality and utilization for improved livestock management and positive environmental benefits. Sub-objective 1A. Forage and biomass production systems that better utilize nutrients to increase productivity and/or reduce energy and nutrient input requirements. Sub-objective 1B. Biomass harvest and storage systems that enhance the value of the feedstock for livestock production. Sub-objective 1C. Efficient strategies for producing livestock on forage-based diets, targeting optimal productivity. Sub-objective 1C1. Identification and selection of animal phenotypes that are productive and thrive on low-input pasture systems to minimize management inputs. Sub-objective 1C2. Understanding grazing behavior and spatial distribution of sheep naturally infected with gastrointestinal nematodes. Objective 2: Develop integrated tools to foster improved management of pasture and forages which maintain productivity while providing economic and environmental benefits. Sub-objective 2A. Measuring and monitoring system status and function at various scales. Sub-objective 2A1. Develop tools to identify environmental factors affecting forage production to maximize productivity and environmental/ecosystem benefits in diverse environments. Sub-objective 2A2. Utilize spatial information to develop site specific recommendations for warm season forage species, nutrient requirements and economic inputs for improved farm management. Sub-objective 2B. Provide tools that support management decisions and aid implementation. Sub-objective 2B1. Determine site specific recommendations coupling soil water availability with nutrient requirements to optimize forage production for economic sustainability. Sub-objective 2B2. Farm-scale recommendations that provides a decision support tools for producers that will allow optimization of farm management for whole farm productivity, economic viability and environmental sustainability. Sub-objective 2C. Pasture-based livestock management practices that improve resilience to climate change, conserve soil or protect water quality, optimizing production, conservation and environmental goals. Sub-objective 2D. Targeted grazing strategies to reduce invasive grasses and forbs and promote desirable perennial grasses and woody species. Sub-objective 2E. Grazing management strategies for maintenance of a diverse native plant pasture that serves livestock and wildlife including native pollinators. Sub-objective 2E1. Impact of grazing on insect pollinators and beneficial arthropod community in pasture ecosystems designed for multiple use of livestock grazing and pollinator habitat. Sub-objective 2E2. Impact of native forbs and grasses on insect pollinators and beneficial arthropods and plant- pollinator interactions in pasture ecosystems designed for multiple use of livestock grazing and pollinator habitat.

Approach
Our goal is to increase long-term sustainability of small farms by integrating management of pasture and silvopasture-based livestock systems to augment whole-farm productivity and profitability, encourage crop diversification which spreads biological and financial risk, and enhances ecosystem services. Involving both short- and long-term studies, we will determine practices that provide environmental and economic benefit to small farms. Studies will focus on improving forage and/or livestock production while enhancing soil, landscape and forage attributes at multiple scales. These studies include examining conventional and nonchemical parasite control on sheep production efficiency, grazing management on forage finished beef and lamb, and improving nutrient-use efficiency on forage pastures. Additionally spatial information will be used to understand interactions at multiple scales to develop decision support tools for increasing efficiency for soil-forage system management. We will also continue a long-term study that utilizes controlled watersheds to determine the impacts of various pasture management strategies (rotational grazing, overgrazing, haying, tree buffers) on pasture hydrology and nutrient runoff. To evaluate diversification, we will examine effects of integrating agroforestry management with crop and/or livestock production.

Progress Report
Sub-objective 1A. Poultry litter was applied by different methods, surface application and subsurface application. Subsurface application utilized an ARS patented prototype that injects litter under the soil surface. Surface treatments used a traditional litter broadcaster and control plots received no litter. Forage was harvested from the plots and sampled for phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), protein, water soluble carbohydrates, and fiber components to determine nutrient utilization among the poultry litter amendment treatments. Statistical analysis has been completed and a manuscript has been drafted and submitted. Sub-objective 1B. A study was conducted on plots amended with surface poultry litter and sub-surface poultry liter and baled at different moistures. Prior to wrapping, bales were sampled with a bale probe and stored for later analysis. Bales were then wrapped and stored until the completion of the ensiling process. Post-ensiled samples were taken approximately 6 months after baling. Pre- and post-ensiled samples were analysis P, K, Ca, Mg, S, protein, waters soluble carbohydrates, and fiber components. These variables were regressed against bale moisture and many relationships were determined. Statistical analysis has been completed and a manuscript drafted and submitted. Subobjective 1C1.1. To determine factors that contribute to reduced fertility in spring breeding ewes. Field experiments have been completed. Forage analyses are pending. Forage data will be analyzed and combined with sheep data to prepare manuscripts. Subobjective 1C1.3. To identify genetic loci associated with resistance to gastrointestinal nematodes in sheep. Five thousand sheep from 21 farms across the U.S. were genotyped using an ovine genotyping array (50K) single nucleotide polymorphisms (SNP) to develop a reference population. All sheep had phenotypes for parasite resistance (fecal egg counts determined around the time of weaning). Since genotyping the reference population associated with a USDA, National Institute of Food and Agriculture, Organic Agricultur Research and Extension Initiative grant, at least twice that number has been submitted and analyzed using the National Sheep Improvement Program (NSIP) by private farmers, universities and USDA, ARS locations (Booneville, Clay Center, Dubois) and genomic estimated breeding values have been implemented (10/2021) in NSIP as a result improving accuracies of the breeding values including parasite resistance. Other outputs were three proceedings papers presented at the World Congress of Genetics for Applied Livestock Production in Rotterdam, Netherlands, and two manuscripts published (Becker et al., 2022; Notter et al., 2022); additional manuscripts are pending. Subobjective 1C2. Understanding grazing behavior and spatial distribution of sheep naturally infected with gastrointestinal nematodes (GIN). Field experiments were completed in 2019 and data are being analyzed for manuscripts. Subobjective 2A1. The plots were established with stands of bermudagrass (Cynodon dactylon L.) and tall fescue for the 3-year study. Soils samples for 3 soil types have been collected and have been anaylyzed. The forages were monitored and sampled for yield, acid detergent fiber (ADF) and neutral detergent fiber (NDF) to related functional soil properties to forage productivity. The manuscripts are being prepared for submission to a journal. Subobjective 2A2. Soil samples have been analyzed for primary, secondary, and micronutrients. Total N concentration were determined and Mehlich-3 of all elements were determined using an inductively coupled plasma spectroscopy (ICP). GPS coordinates of each site were recorded using a hand-held GPS unit. A digital elevation moded (DEM) of 1 m x 1m grid spacing was used to extract 20 terrain attributes within SAGAGIS and ArcGIS platforms for topographic information. These terrain attributes have been linked with soil properties to compare to forage metrics. For tree species, we have measured growth and estimated biomass. There were two manuscripts developed and published that are focused on this objective. Subobjective 2B1. Topsoil samples from tree alleys were collected based on topographic position representing high, low, and medium elevations. Samples were analyzed for nitrogen (N), P, K, Ca, Mg, S, iron (Fe), sodium (N), manganese (Mn), zinc (Z), copper (Cu), and boron (B). Total N was determined by high-temperature combustion. Mehlich-3 extractions of P, K, Ca, Mg, S, Fe, Na, Mn, Zn, Cu, and B were determined using an ICP. GPS coordinates of each point were recorded using a hand-held GPS unit. The data collected is being utilized to identify topographic functional units (TFU) using terrain attributes where the individual units are more homogeneous in terms of terrain properties and behave as a single functional unit in a landscape. The data have been analyzed and a manuscript is being developed. Subobjective 2B2. The field data has been collected using drivers with different levels of experience. The field topography and morphology is currently being analyzed to relate field shapes to driver experience to compare with precision auto-steer. The gaps and overlaps were calculated to relate to efficiency gains or losses. A manuscript has been submitted to a journal and accepted for publication. Subobjective 2C. The 15 small watersheds (0.35 acre, 8% slope) are equipped with flumes and automatic water samplers. There are 5 treatments being evaluated with 3 replications per treatment in a completely randomized design. The treatments are; (1) hayed only, (2) over-grazed (continuous heavy grazing), (3) rotational grazing, (4) rotational grazing with an unfertilized buffer strip and (5) rotational grazing with an unfertilized riparian buffer. Sward height is monitored to ensure that overgrazing does not occur on the rotational grazing treatments. Samples have been collected for each runoff event and analyzed for pH, electrical conductivity, total P, SRP, soluble metals, total metals, total N, nitrate-N, ammonium-N, total solids, and total organic carbon. Soil samples are analyzed for Mehlich 3 P, and soluble reactive phosphorus (SRP) (10:1 soil:deionized water). Data collection is ongoing and will be summarized for publication after 3 years of data collection. Subobjective 2D. Targeted grazing strategies to reduce invasive grasses and forbs and promote desirable perennial grasses and woody species. Field research was completed and a publication is pending. Subobjective 2E1. Impact of grazing on insect pollinators and beneficial arthropod community in pasture ecosystems designed for multiple use of livestock grazing and pollinator habitat. Field experiments were completed in 2019. A graduated student completed her Ph.D. associated with this objective. A manuscript is in preparation. Subobjective 2E2. Impact of native forbs and grasses on insect pollinators and beneficial arthropods and plant-pollinator interactions in pasture ecosystems designed for multiple use of livestock grazing and pollinator habitat. Field experiments were completed in 2019. A graduated student completed her Ph.D. associated with this objective. Manuscripts have been published (Acharya et al., 2021; 2022).

Accomplishments
1. Use of genomics and phenotypes to improve production and parasite resistance in sheep. Cattle have been using genomic-enhanced estimated breeding values for accurate genetic selection for economic traits for years, but the technology has not been available in U.S. sheep. Coupling genomics with phenotypes (or data measurements on sheep) recorded from farmers participating in the National Sheep Improvement Program (NSIP) will increase accuracy of estimated breeding values (EBV; genetic predictions) including growth, reproduction, and parasite resistance traits. ARS researchers in Booneville, Arkansas, University of Nebraska-Lincoln, Virginia Tech, University of Idaho, Louisiana State University, and University of New England, Australia collected sheep DNA from ARS and 21 farms across the U.S. to generate a reference database of 5000 genotypes and validated improved genetic evaluations leading to implementation of genomic-enhanced EBV in NSIP improving accuracies of prediction. In addition, genes were identified using genomic techniques to determine associations with parasite resistance. This information is important to sheep producers, scientists, geneticists, veterinarians, and extension specialists across the globe aiming to improve genetic parameters in sheep.

2. Use of sub-surface poultry litter injection for greater nutrient utilization in fall seeded winter annuals. Injection of liquid livestock manures on crop fields is common in regions with high dairy production, however, injection of dry poultry litter is less common, even in areas with high poultry production, despite benefits of improved nutrient utilization for hay and pastures. Injection of poultry litter under the soil surface (sub-surface) improves nutrient utilization compared to broadcast (surface) application through reduced nutrient runoff and increased forage nutritive value. ARS researchers in Booneville, Arkansas, ARS-Marshfield, Wiconsin, and University of Arkansas evaluated yield and nutrient composition of winter annual forages with poultry litter applied by sub-surface, surface, or a control plot with no poultry litter. Results indicated that sub-surface application increased yield from cereal rye-ryegrass plots compared to surface and control plots. Nutritional content of forage was not influenced by application method, but application method did influence botanical composition. Although increases in plant nitrogen are expected with poultry litter fertilization, greater percentages of volunteer vegetative tall fescue in surface and control plots maintained similar crude protein levels as sub-surface plots with greater yields of boot stage cereal rye. This information is important to forage producers in the southeast because of the prevalence of poultry production and farmers’ interest in improving nutrient utilization in winter annual forages.

3. Agriculture is entering the digital age where data-driven management approaches will increase with increased analytics. In research conducted at the Dale Bumpers Small Farms Research Center, ARS researchers in Booneville, Arkansas, have identified diverse of crop responses related to soils and landscapes. Combining digital predictions of soil properties with digital terrain features, there was distinct and predictable plant responses. In a silvopasture site, the soil-terrain combinations identified areas that were well drained and at higher elevations, where the oak species were rapidly growing and other species such as poplar were slower growing. In the lower elevation areas with high water tables, the poplar trees grew at a faster rate than the oak species. Similarly, in row crop corn fields, the soil-terrain combinations were compared to yield monitor data. The data indicated that soils on slopes with lower water holding capacity consistently had lower yields across fields and soils with high water holding capacity on flat slopes consistently had higher yields across years. These unique data combinations are important for precision management to decrease fertilizer use and optimize profits.

Review Publications
Whitley, N.C., Burke, J.M., Smith, E., Lyte, K., Terrill, T.H. 2022. Determining the efficacy of Red Cell® in combination with anthelmintics against gastrointestinal nematode parasitism in sheep and goats. Small Ruminant Research. 209(26):106656. https://doi.org/10.1016/j.smallrumres.2022.106656.
Jiang, Z., Owens, P.R., Ashworth, A.J., Fuentes, B.A., Thomas, A.L., Sauer, T.J., Wang, Q. 2021. Evaluating tree growth factors into species-specific functional soil maps for improved agroforestry system efficiency. Agroforestry Systems. https://doi.org/10.1007/s10457-021-00693-9.
Guillaume, T., Makowski, D., Libohova, Z., Bragazza, L., Sallaku, F., Sinaj, S. 2021. Soil organic carbon saturation in cropland-grassland systems: storage potential and soil quality. Geoderma. 406. Article 115529. https://doi.org/10.1016/j.geoderma.2021.115529.
Richer-De-Forges, A.C., Arrouays, D., Chen, S., Roman Dobarco, M., Libohova, Z., Roudier, P., Minasny, B., Bourennane, H. 2022. Hand-feel soil texture and particle-size distribution in Central France. Relationships and implications. Catena. https://doi.org/10.1016/j.catena.2022.106155.
Becker, G.M., Burke, J.M., Lewis, R.M., Miller, J.E., Morgan, J.L., Rosen, B.D., Van Tassell, C.P., Notter, D.R., Murdoch, B. 2022. Variants within genes EDIL3 and ADGRB3 are associated with divergent fecal egg counts in Katahdin sheep at weaning. Frontiers in Genetics. https://doi.org/10.3389/fgene.2022.817319.
Han, C., Sun, Z., Shao, S., Wang, Q., Libohova, Z., Owens, P.R. 2021. Changes of soil organic carbon after wildfire in a Boreal Forest, Northeast China. Agronomy Journal. 11(10):1925. https://doi.org/10.3390/agronomy11101925.
Acharya, R.S., Leslie, T., Fitting, E., Burke, J.M., Loftin, K., Joshi, N.K. 2021. Color of pan trap influences sampling of bees in livestock pasture ecosystem. Nature Scientific Reports. 10(5):445. https://doi.org/10.3390/biology10050445.
Sun, Z., Jiang, Y., Wang, Q., Jiang, Z., Libohova, Z., Owens, P.R. 2022. Characteristics of a benchmark loess-paleosol profile in Northeast China. Agronomy Journal. https://doi.org/10.3390/agronomy12061376.
Notter, D.R., Heidaritabar, M., Burke, J.M., Shirali, M., Murdoch, B., Morgan, J.L., Morota, G., Sonstegard, T., Becker, G., Spangler, G.L., Macneil, M.D., Miller, J.E. 2022. Single nucleotide polymorphism effects on lamb fecal egg count estimated breeding values in progeny-tested Katahdin sires. Frontiers in Genetics. 13:866176. https://doi.org/10.3389/fgene.2022.866176.
Nieman, C.C., Coblentz, W.K., Coffey, K.P. 2021. Application of poultry litter and moisture effects on rye-ryegrass fescue baleage. Crop, Forage & Turfgrass Management. 7(2):e20118. https://doi.org/10.1002/cft2.20118.
Conway, A.C., Nieman, C.C. 2022. Small-scale silvopasture: addressing urban and peri-urban livestock challenges in the United States with agroforestry practices. Urban Agriculture and Regional Food Systems. https://doi.org/10.1002/uar2.20023.
Hysa, A., Teqja, Z., Bani, A., Libohova, Z., Cerda, A. 2022. Assessing wildfire vulnerability of vegetated serpentine soils in the Balkan peninsula. Nature Conservation. https://doi.org/10.1016/j.jnc.2022.126217.
Guillaume, T., Makowski, D., Libohova, Z., Elfouki, S., Fontana, M., Leifeld, J., Bragazza, L., Sinaj, S. 2022. Carbon storage in agricultural topsoils and subsoils is promoted by including temporary grasslands into the crop rotation. Geoderma. https://doi.org/10.1016/j.geoderma.2022.115937.
Minai, O.J., Schulze, D., Libohova, Z. 2022. Renewal of archival legacy soil data: A case study of the Busia Area, Kenya. Frontiers in Soil Science. https://doi.org/10.3389/fsoil.2021.765248.
Shamrikova, E.V., Kondratenok, B.M., Tumanova, E.A., Vanchikova, E.V., Lapteva, E.M., Zonova, T.N., Lu-Lyan-Min, E.I., Davydova, A.P., Libohova, Z., Suvannang, N. 2021. Transferability between soil organic matter measurement methods for database harmonization. Geoderma. https://doi.org/10.1016/j.geoderma.2021.115547.
Rahmani, S.R., Ackerson, J., Schulze, D., Adhikari, K., Libohova, Z. 2022. Digital mapping of soil organic matter and cation exchange capacity in a low relief lanscape using LiDAR data. Agronomy Journal. https://doi.org/10.3390/agronomy12061338.
Blackburn, K., Libohova, Z., Adhikari, K., Kome, C., Maness, X., Silman, R.M. 2022. Influence of land use and topographic factors on soil organic carbon stocks and their spatial and vertical distribution. Remote Sensing. https://doi.org/10.3390/rs14122846.
Jiang, Z., Owens, P.R., Zhang, C., Brye, K.R., Weindorf, D.C., Adhikari, K., Sun, Z., Sun, F., Wang, Q. 2021. Towards a dynamic soil survey: Identifying and delineating soil horizons in-situ using deep learning. Geoderma. 401. Article 115341. https://doi.org/10.1016/j.geoderma.2021.115341.
Adhikari, K., Smith, D.R., Hajda, C.B., Owens, P.R. 2022. Can soil health explain grain quality? A case study of a corn field in Texas. Agricultural & Environmental Letters. 7. Article e20078. https://doi.org/10.1002/ael2.20078.
Webber, J.B., Gordon, D., Rosati, A., Meier, N., Gold, M., Revord, R. 2022. Postharvest spoilage incidence and prestorage treatment in Chinese chestnut and complex hybrid cultivars. HortTechnology. 32(2):164-171. https://doi.org/10.21273/HORTTECH04981-21.
Vu, D.C., Park, J., Van Ho., Sumner., W. Lei., Greenlief, C., Mooney, B., Coggeshall, M.V., Ho Lin, C. 2019. Identification of health-promoting bioactive phenolics in black walnut using cloud-based metabolomics platform. Journal of Food Measurement and Characterization. 14:770–777. https://doi.org/10.1007/s11694-019-00325-y.
Taleghani, A., Lim, T., Lin, C., Ericsson, A.C., Vo, P.H. 2020. Degradation of sulfamethazine in swine manure via anaerobic digestion. Bioengineering. https://doi.org/10.3390/bioengineering7040123.
Seruni, A.P., Aguilar, F., Gold, M.A., Roshetko, J.M. 2020. Parcelized cut-and-carry agroforestry systems for confined livestock. Small-Scale Forestry. Small-scale Forestry. https://doi.org/10.1007/s11842-020-09460-7.
Salceda, M., Udawatta, R.P., Nelson, K.A., Mendis, S.S., Bardhan, S. 2021. Spatial and temporal variability of soil organic carbon on a corn-soybean watershed with 23 years of agroforestry. Agronomy Journal. 114(1):440-451. https://doi.org/10.1002/agj2.20948.
Rogers, E.R., Zalesny Jr., R.S., Lin, C. 2021. A systematic approach for prioritizing landfill pollutants based on toxicity: Applications and opportunities. Environmental Management. https://doi.org/10.1016/j.jenvman.2021.112031.
Revord, R.S., Miller, G., Meier, N.A., Webber, J., Romero-Severson, J., Gold, M.A., Lovell, S.T. 2022. A roadmap for participatory chestnut breeding for nut production in the eastern United States. Frontiers in Plant Science. https://doi.org/10.3389/fpls.2021.735597.
Revord, R.S., Lovell, S.T., Brown, P., Capik, J., Molnar, T.J. 2020. Using genotyping-by-sequencing derived SNPs to examine the genetic structure and identify a core set of Corylus americana germplasm. Tree Genetics and Genomes. https://doi.org/10.1007/s11295-020-01462-y.
Hsieh, H., Lin, C., Hsu, S., Stewart, G.C. 2020. A bacillus spore-based display system for bioremediation of atrazine. Applied and Environmental Microbiology. https://doi.org/10.1128/AEM.01230-20.
Ho, K., Schreiber, K.L., Park, J., Vo, P.H., Lei, Z., Sumner, L.W., Brown, C.R., Lin, C. 2020. Identification and quantification of bioactive molecules inhibiting pro-inflammatory cytokine production in spent coffee grounds using metabolomics analyses. Frontiers in Pharmacology. https://doi.org/10.3389/fphar.2020.00229.
Ho, K., Roy, A., Foote, S., Vo, P.H., Lall, N., Lin, C. 2020. Profiling anticancer and antioxidant activities of phenolic compounds present in black walnuts (Juglans nigra) using a high-throughput screening approach. Molecules. https://doi.org/10.3390/molecules25194516.
Kharel, T.P., Ashworth, A.J., Owens, P.R., Philipp, D., Thomas, A.L., Sauer, T.J. 2021. Teasing apart silvopasture system components using machine learning for optimization. Soil Systems. https://doi.org/10.3390/soilsystems5030041.
Diabla, R., Jose, S., Gold, M., Hall, J.S., Kallenbach, R., Knapp, B. 2021. Tree density effects on soil, herbage mass and nutritive value of understory Megathyrsus maximus in a seasonally dry tropical silvopasture in Panama. Agroforestry Systems. 95:741-753. https://doi.org/10.1007/s10457-021-00628-4.
Bayati, M., Vu, D.C., Vo, P.H., Rogers, E., Park, J., Ho, T.L., Davis, A.N., Gulseven, Z., Carlo, G., Palermo, F., Mcelroy, J.A., Nagel, S.C., Lin, C. 2021. Health risk assessment of volatile organic compounds at daycare facilities. International Journal of Environmental Research and Public Health. https://doi.org/10.1111/ina.12801.
Bayati, M., Ho, T.L., Vu, D.C., Wang, F., Rogers, E., Cuvellier, C., Huebotter, S., Inniss, E.C., Udawatta, R., Jose, S., Lin, C. 2020. Assessing the efficiency of constructed wetlands in removing PPCPs from treated wastewater and mitigating the ecotoxicological impacts. International Journal of Hygiene and Environmental Health. 231:113664. https://doi.org/10.1016/j.ijheh.2020.113664.
Appenteng, M.K., Krueger, R., Johnson, M.C., Ingold, H., Bell, R., Thomas, A.L., Greenlief, C.M. 2021. Cyanogenic glycoside analysis in American elderberry. Molecules. 26:1384. https://doi.org/10.3390/molecules26051384.
Alagele, S.M., Anderson, S.H., Udawatta, R.P. 2020. Agroforestry, grass, biofuel crop, and row-crop management effects on soil water dynamics for claypan landscapes. Soil Science Society of America Journal. 84:203-219. https://doi.org/10.1002/saj2.20026.
Aguilar, F.X., Hendrawan, D., Cai, Z., Roshetko, J.M., Stallmann, J. 2021. Smallholder farmer resilience to water scarcity. Environment, Development and Sustainability. 24:2543-2576. https://doi.org/10.1007/s10668-021-01545-3.
Geisert, R.D., Johns, D.N., Pfeiffer, C.A., Sullivan, R.M., Lucas, C.G., Simintiras, C.A., Redel, B.K., Wells, K.D., Spencer, T.E., Prather, R.S. 2022. Gene editing provides a tool to investigate genes involved in reproduction of pigs. Molecular Reproduction and Development. 1-10. https://doi.org/10.1002/mrd.23620.
Nieman, C.C., Coffey, K.P., Young, A.N., Kegley, E.B., Hornsby, P., Hollenback, J., Philipp, D. 2022. Intake, digestibility, and rumen fermentation by lactating beef cows offered bermudagrass hay with different sources of dried distillers grains. Applied Animal Science. https://doi.org/10.15232/aas.2021-02236.
Hemmelgarn, H.L., Munsell, J.F. 2021. Exploring ‘beyond-food’ opportunities for biocultural conservation in urban forest gardens. Urban Agriculture and Regional Food Systems. https://doi.org/10.1002/uar2.20009.
Ashworth, A.J., Nieman, C.C., Adams, T.C., Franco Jr, J.G., Owens, P.R. 2022. Subsurface banding poultry litter influences edamame yield, forage quality, and leaf greenness. Agronomy Journal. 114(3):1833-1841. 10.1002/agj2.21048.
Ashworth, A.J., Nieman, C.C. 2022. Evaluating optimum seeding distances from subsurface banding poultry litter in crop rotations. Agricultural & Environmental Letters. 7(1). Article e20063. https://doi.org/10.1002/ael2.20063.
Romanova, O., Lovell, S. 2021. Food safety considerations of urban agroforestry systems grown in contaminated environments. Urban Agriculture and Regional Food Systems. https://doi.org/10.1002/uar2.20008.
Revord, R.S., Lovell, S.T., Brown, P., Capik, J., Molnar, T.J. 2020. Using genotyping-by-sequencing derived SNPs to examine the genetic structure and identify a core set of Corylus americana germplasm. Tree Genetics and Genomes. https://doi.org/10.1007/s11295-020-01462-y.
Revord, R.S., Nave, M.J., Miller, G., Meier, N., Webber, B.J., Gold, M.A., Wahl, T. 2021. Descriptions of chestnut cultivars for nut production in the eastern and midwestern U.S. HortScience. 56(11):1315-1324. https://doi.org/10.21273/HORTSCI16090-21.
Mendelson, S., Gold, M., Lovell, S., Hendrickson, M. 2021. The agroforestry academy: Assessing long-term outcomes and impacts of a model training program. Agroforestry Systems. https://doi.org/10.1007/s10457-021-00604-y.
Rossiter, D.G., Poggio, L., Beaudette, D., Libohova, Z. 2021. How well does Predictive Soil Mapping represent soil geography? An investigation from the USA. Soil. https://doi.org/10.5194/soil-2021-80.