@article{touchell_ranney_panthee_gehl_krings_2016, title={Genetic diversity, cytogenetics, and biomass yields among taxa of giant reeds (Arundo species)}, volume={141}, number={3}, journal={Journal of the American Society for Horticultural Science}, author={Touchell, D. H. and Ranney, T. G. and Panthee, D. R. and Gehl, R. J. and Krings, A.}, year={2016}, pages={256–263} }
 @article{teat_neufeld_gehl_gonzales_2015, title={Growth and Yield of Miscanthus x giganteus Grown in Fertilized and Biochar-Amended Soils in the Western North Carolina Mountains}, volume={80}, ISSN={["1938-4386"]}, DOI={10.2179/14-021r1}, abstractNote={ABSTRACT Miscanthus × giganteus Greef & Deu (giant miscanthus) is a perennial C4 grass grown worldwide for bioenergy production; however, there is concern about whether it can produce high yields on marginal soils in a temperate climate. The goals of this study were to determine whether giant miscanthus could establish and produce yields in Western North Carolina comparable to those in other regions and to determine whether fertilization and biochar could improve yields. At two field sites, Mills River (650 m) and Valle Crucis (830 m), fertilizer (0 and 100 kg NPK ha−1) and biochar (0 and 15 t ha−1) treatments were employed in a fully randomized block design. Genetically identical rhizomes were planted in spring of 2012 and allowed to grow for two growing seasons. No treatment effects were found for gas exchange, but rates were higher at Mills River than at Valle Crucis. There were no biochar or fertilizer effects on yields. First-year yields were greater at Mills River than at Valle Crucis (2.93 and 1.77 Mg dry weight [DW] ha−1, respectively). Overwinter survival rates were 100% at both field sites. Second-year yields were approximately 10× greater than in the first year (27.68 Mg DW ha−1 at Mills River vs. 30.12 Mg DW ha−1 at Valle Crucis). The high survival and growth rates during the first 2 yr demonstrate that this bioenergy crop is capable of growing in Western North Carolina and producing yields comparable to those in other areas of the country where this crop has been grown.}, number={1}, journal={CASTANEA}, author={Teat, Alyssa L. and Neufeld, Howard S. and Gehl, Ronald J. and Gonzales, Eva}, year={2015}, month={Mar}, pages={45–58} }
 @article{haines_gehl_havlin_ranney_2015, title={Nitrogen and Phosphorus Fertilizer Effects on Establishment of Giant Miscanthus}, volume={8}, ISSN={["1939-1242"]}, DOI={10.1007/s12155-014-9499-4}, number={1}, journal={BIOENERGY RESEARCH}, author={Haines, S. A. and Gehl, R. J. and Havlin, J. L. and Ranney, T. G.}, year={2015}, month={Mar}, pages={17–27} }
 @article{palmer_gehl_ranney_touchell_george_2014, title={Biomass yield, nitrogen response, and nutrient uptake of perennial bioenergy grasses in North Carolina}, volume={63}, ISSN={["1873-2909"]}, DOI={10.1016/j.biombioe.2014.02.016}, abstractNote={Although perennial grasses show considerable potential as candidates for lignocellulosic bioenergy production, these crops exhibit considerable variation in regional adaptability and yield. Giant miscanthus (Miscanthus × giganteus Greef & Deuter), Miscanthus sinensis Anderss. 'Gracillimus' and MH2006, plume grass (Saccharum arundinaceum Retz.), ravenna grass (Saccharum ravennae (L.) L.), switchgrass (Panicum virgatum L. 'Alamo'), and giant reed (Arundo donax L.) field plots were established in 2008, treated with four nitrogen (N) fertilizer rates (0, 34, 67, 134 kg ha−1 y−1), and harvested annually in winter from 2008 to 2011. Giant reed, 'Gracillimus', switchgrass, MH2006, giant miscanthus and ravenna grass at the Mountain site produced mean dry matter yields of 22.8, 21.3, 20.9, 19.3, 18.4, and 10.0 Mg ha−1 y−1, respectively (averaged over the last two years). Dry matter yields at the Coastal site for giant reed, giant miscanthus, switchgrass, ravenna grass, and 'Gracillimus' were 27.4, 20.8, 20.1, 14.3, and 9.4 Mg ha−1 y−1, respectively (averaged over the last two years). Increasing N rates up to 134 kg N ha−1 did not have a consistent significant effect on biomass production. High yields coupled with high mortality for plume grass at both sites indicates its potential as a bioenergy crop and need for continued improvement. Overall, the perennial grasses in this study had low nutrient removal, although giant reed and plume grass often removed significantly more N, P, K and S compared with Miscanthus spp. and switchgrass. Our results indicate that giant reed, giant miscanthus, and switchgrass are productive bioenergy crops across geographic regions of North Carolina.}, journal={BIOMASS & BIOENERGY}, author={Palmer, Irene E. and Gehl, Ronald J. and Ranney, Thomas G. and Touchell, Darren and George, Nic}, year={2014}, month={Apr}, pages={218–228} }
 @article{crozier_gehl_hardy_heiniger_2014, title={Nitrogen Management for High Population Corn Production in Wide and Narrow Rows}, volume={106}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2013.0280}, abstractNote={Recent trends of planting corn (Zea mays L.) at higher populations and in narrower rows could influence optimum N management. This study investigates the effects of N rates (0–224 kg ha–1 N plus a low rate of uniformly applied starter) and timing (at planting, V5–V7 sidedress) on corn in wide and narrow rows (76–102 cm vs. 38–51 cm) at 13 sites over 3 yr in North Carolina. Early season N uptake, grain yield, and yield components were measured. Delaying N until sidedress increased yields, but there was an interaction effect with row spacing. Yields were greater with narrow rows and sidedress N (11.7 Mg ha–1) than with narrow rows and all N at planting (11.0 Mg ha–1) or with wide rows fertilized at either time (11.0 Mg ha–1), when averaged across N rates. Three ear yield components increased in response to N fertilization, leading to a 35% yield increase. Rows per ear increased from 15.5 to 15.9 ear–1, kernels per row increased from 27 to 32 row–1, and individual kernel mass increased from 226 to 253 mg. Aboveground plant N uptake by the V5 to V7 growth stage was only 9 kg ha–1, with very little additional N uptake in response to higher N rates. Sidedress N application at V5 to V7 maximized the formation of the ear yield components and grain yield for high population corn in narrow rows, but N timing did not affect yield or ear yield components of wide‐row corn.}, number={1}, journal={AGRONOMY JOURNAL}, author={Crozier, Carl R. and Gehl, Ronald J. and Hardy, David H. and Heiniger, Ronnie W.}, year={2014}, pages={66–72} }
 @article{havlin_hardy_gehl_spayd_2012, title={Survey of Nutrient Status in Vitis vinifera Grapes in North Carolina}, volume={43}, ISSN={["0010-3624"]}, DOI={10.1080/00103624.2011.638600}, abstractNote={Grape (Vitis vinifera L.) production is a rapidly growing industry in North Carolina; however, no local-research-based information is available to support nutrient-management decisions. Field studies were initiated to survey soil and plant nutrient status over a wide range in geography and management conditions in the dominant V. vinifera regions in North Carolina. While the survey data are still being analyzed, significant information was initially obtained to identify aluminum toxicity and phosphorus and potassium deficiency as potential limiting factors to vine health and productivity. Field studies were initiated to quantify soil test and plant nutrient responses to lime, phosphorus, and potassium rates. Responses to phosphorus and potassium application were observed at most sites predicted by soil tests. However, lime responses were not observed in either petiole or blade samples collected at full bloom or veraison. These studies will be continued until sufficient response data are collected to establish soil test and plant nutrient diagnostic criteria for efficient nutrient management of V. vinifera in North Carolina.}, number={1-2}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Havlin, J. L. and Hardy, D. H. and Gehl, R. J. and Spayd, S. E.}, year={2012}, pages={299–314} }
 @article{biai_garzon_osborne_schultheis_gehl_gunter_2011, title={Height control in three pepper types treated with drench-applied abscisic acid}, volume={46}, number={9}, journal={HortScience}, author={Biai, C. J. and Garzon, J. G. and Osborne, J. A. and Schultheis, J. R. and Gehl, R. J. and Gunter, C. C.}, year={2011}, pages={1265–1269} }
 @article{gehl_boring_2011, title={In-Season Prediction of Sugarbeet Yield, Quality, and Nitrogen Status Using an Active Sensor}, volume={103}, ISSN={["0002-1962"]}, DOI={10.2134/agronj2011.0040}, abstractNote={Nitrogen fertilizer management of sugarbeet (Beta vulgaris L.) continues to increase in importance with rising fertilizer costs and industry payments weighted toward crop quality. Our objective was to evaluate the use of an optical sensor for assessment of in‐season sugarbeet N status, yield, and quality prediction and total N in foliage on the day of harvest. Six N fertilizer treatments, from 0 to 225 kg N ha−1, were applied at three sites in Michigan in 2006 and four sites in 2007. Normalized difference vegetative indices (NDVIs) were measured at four growing degree day (GDD) intervals in 2006, five intervals in 2007, and at harvest in both years with a red‐band active sensor. Leaf biomass and root yield were determined at harvest, and root samples were collected for determination of sucrose content and clear juice purity. The NDVI readings were useful for differentiating control treatments from fertilized plots but were not able to identify a yield response threshold until late in the season. Midseason 1200 to 1400 GDD, 1900 to 2300 GDD, and harvest NDVI values were strongly related to recoverable white sucrose per area (R2 = 0.89, 0.87, and 0.80, respectively). Harvest NDVI was strongly related to sugarbeet vegetation total N (R2 = 0.87). Active sensing during the growing season shows promise as a means to estimate root yield and recoverable sugar in sugarbeet fields. Sensing on the day of harvest may improve rotational N management by providing an indication of N return to the cropping system.}, number={4}, journal={AGRONOMY JOURNAL}, author={Gehl, Ronald J. and Boring, Timothy J.}, year={2011}, pages={1012–1018} }
 @article{hoben_gehl_millar_grace_robertson_2011, title={Nonlinear nitrous oxide (N2O) response to nitrogen fertilizer in on-farm corn crops of the US Midwest}, volume={17}, ISSN={["1365-2486"]}, DOI={10.1111/j.1365-2486.2010.02349.x}, abstractNote={Abstract}, number={2}, journal={GLOBAL CHANGE BIOLOGY}, author={Hoben, J. P. and Gehl, R. J. and Millar, N. and Grace, P. R. and Robertson, G. P.}, year={2011}, month={Feb}, pages={1140–1152} }
 @article{gao_thelen_min_smith_hao_gehl_2010, title={Effects of Manure and Fertilizer Applications on Canola Oil Content and Fatty Acid Composition}, volume={102}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2009.0368}, abstractNote={Increasing fertilizer costs have resulted in more growers evaluating the use of alternative nutrient sources such as manure. Coincidentally, the questions about fertilizer effects on oil yield and oil fatty acid composition have been a concern. A 2‐yr study was conducted to investigate nutrient source (fertilizer urea plus S and manure) and N level (0, 84, and 168 kg N ha−1) effects on canola seed yield, total oil content, and oil composition at East Lansing and Chatham, MI. Results indicated nutrient applications were not necessary to increase canola yield (865–1991 kg ha−1) in fertile fields. However, N fertilizer appeared to reduce total oil content (444−536 mL kg−1), and at similar N levels, total oil content in canola with fertilizer was sometimes lower than that with manure application. Compared with the no nutrient control treatment, fertilizer application sometimes decreased linolenic acid (LN) content, and increased palmitic acid (P) and arachidic acid (A) at Chatham, while it appeared to decrease oleic acid (O) and increase P, linoleic (L) and A at East Lansing. Fertilizer applications often increased canola total saturated fatty acid content (6.80–8.32%) and decreased ratio of O/(L+LN) (2.04–2.52). Manure application had milder effects on oil composition than fertilizer application. Compared with less N (84 kg N ha−1) applications, greater N level (168 kg N ha−1) tended to lower oil quality by increasing total saturated fatty acid content and decreasing the O/(L+LN) ratio.}, number={2}, journal={AGRONOMY JOURNAL}, author={Gao, Juan and Thelen, Kurt D. and Min, Doo-Hong and Smith, Stephanie and Hao, Xinmei and Gehl, Ron}, year={2010}, pages={790–797} }
 @article{millar_robertson_grace_gehl_hoben_2010, title={Nitrogen fertilizer management for nitrous oxide (N2O) mitigation in intensive corn (Maize) production: an emissions reduction protocol for US Midwest agriculture}, volume={15}, ISSN={["1573-1596"]}, DOI={10.1007/s11027-010-9212-7}, abstractNote={Nitrous oxide (N2O) is a major greenhouse gas (GHG) product of intensive agriculture. Fertilizer nitrogen (N) rate is the best single predictor of N2O emissions in row-crop agriculture in the US Midwest. We use this relationship to propose a transparent, scientifically robust protocol that can be utilized by developers of agricultural offset projects for generating fungible GHG emission reduction credits for the emerging US carbon cap and trade market. By coupling predicted N2O flux with the recently developed maximum return to N (MRTN) approach for determining economically profitable N input rates for optimized crop yield, we provide the basis for incentivizing N2O reductions without affecting yields. The protocol, if widely adopted, could reduce N2O from fertilized row-crop agriculture by more than 50%. Although other management and environmental factors can influence N2O emissions, fertilizer N rate can be viewed as a single unambiguous proxy—a transparent, tangible, and readily manageable commodity. Our protocol addresses baseline establishment, additionality, permanence, variability, and leakage, and provides for producers and other stakeholders the economic and environmental incentives necessary for adoption of agricultural N2O reduction offset projects.}, number={2}, journal={MITIGATION AND ADAPTATION STRATEGIES FOR GLOBAL CHANGE}, author={Millar, Neville and Robertson, G. Philip and Grace, Peter R. and Gehl, Ron J. and Hoben, John P.}, year={2010}, month={Feb}, pages={185–204} }
 @article{millar_robertson_grace_gehl_hoben_2010, title={Nitrogen fertilizer management for nitrous oxide (N2O) mitigation in intensive corn (Maize) production: an emissions reduction protocol for US Midwest agriculture (vol 15, pg 185, 2010)}, volume={15}, ISSN={["1381-2386"]}, DOI={10.1007/s11027-010-9222-5}, number={4}, journal={MITIGATION AND ADAPTATION STRATEGIES FOR GLOBAL CHANGE}, author={Millar, Neville and Robertson, G. Philip and Grace, Peter R. and Gehl, Ron J. and Hoben, John P.}, year={2010}, month={Apr}, pages={411–411} }