@article{rogers_bian_krakowsky_peters_turnbull_nelson_holland_2022, title={Genomic prediction for the Germplasm Enhancement of Maize project}, volume={10}, ISSN={["1940-3372"]}, url={https://doi.org/10.1002/tpg2.20267}, DOI={10.1002/tpg2.20267}, abstractNote={Abstract}, journal={PLANT GENOME}, author={Rogers, Anna R. and Bian, Yang and Krakowsky, Matthew and Peters, David and Turnbull, Clint and Nelson, Paul and Holland, James B.}, year={2022}, month={Oct} }
 @article{niedziela_depa_nelson_willits_peet_dickey_mingis_2018, title={Effects of Carbon Dioxide and Photosynthetic Photon Flux on Mineral Content in Chrysanthemum Allowing for Growth as a Covariate}, volume={53}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci12425-17}, abstractNote={The effect of CO2 concentration (330 and 675 μL·L−1) and photosynthetic photon flux (PPF) (mean daily peaks of 550–1400 μmol·m−2·s−1) on total mineral contents in shoots was studied in chrysanthemum [Dendranthema ×grandiflorum (Ramat) Kitam ‘Fiesta’] during three times of the year. Growth (as measured by shoot dry weight) and shoot mineral contents (weight of nutrient per shoot) of hydroponically grown plants were analyzed after 5 weeks. There was a positive synergistic interaction of CO2 concentration and PPF on growth with the greatest growth at high PPF (1400 μmol·m−2·s−1) with high CO2 (675 μL·L−1). When growth was not used as a covariate in the statistical model, both CO2 concentration and PPF significantly affected the content of all eight nutrients. However, after growth was included as a covariate in the model, nutrients were classified into three categories based on whether CO2 concentration and PPF level were needed in addition to growth to predict shoot nutrient content. Neither CO2 concentration nor PPF level was needed for Mg, Fe, and Mn contents, whereas PPF level was needed for N, P, K, and Ca contents, and both CO2 concentration and PPF level were required for B content.}, number={1}, journal={HORTSCIENCE}, author={Niedziela, Carl E., Jr. and Depa, Mary A. and Nelson, Paul V. and Willits, Daniel H. and Peet, Mary M. and Dickey, David A. and Mingis, Nancy C.}, year={2018}, month={Jan}, pages={73–77} }
 @article{henry_mccall_nelson_whipker_2018, title={Source-sink interactions lead to atypical reproductive stage phosphorus deficiency symptoms on the upper foliage of Capsicum annuum and Chrysanthemum x morifolium}, volume={238}, ISSN={["1879-1018"]}, DOI={10.1016/j.scienta.2018.04.069}, abstractNote={Phosphorus (P) restriction has become more prevalent in floriculture production to control growth and reduce fertilizer waste. With low P fertilization practices, growers are more likely to develop P deficiency in their crops. Symptoms of a reproductive stage P deficiency were reported in which symptomology occurs on the foliage directly below the flowers or fruit. To induce and describe these symptoms, ornamental peppers (Capsicum annuum L.) and chrysanthemums (Chrysanthemum ×morifolium Ramat.) were grown initially with P fertilization, but half the plants were later restricted to 0 mg L−1 P upon floral initiation. Plants that were P restricted developed symptoms of chlorosis, olive green spotting, and necrosis on the upper foliage below the reproductive structures, while central foliage remained asymptomatic. ‘Crystal Misty Purple’ chrysanthemums developed unique symptoms of upper leaf purpling. Phosphorus movement within the plant was quantified via tissue division and analysis. The highest tissue P concentrations were in the flowers or fruit for both species, regardless of symptoms. Up to 80% of the total P in aboveground tissues was in the flowers and fruit of symptomatic plants. Vegetative tissue P concentrations were significantly lower in symptomatic plants compared to the asymptomatic controls, indicating that large quantities of P were translocated from vegetative tissues to the developing reproductive tissues. Remobilized P from the lower tissues appeared to bypass the upper foliage in favor of the flowers and fruit. Thus, the developing upper foliage was deprived of P, leading to P deficiency symptoms due to competition with the maturing flowers and fruit.}, journal={SCIENTIA HORTICULTURAE}, author={Henry, Josh B. and McCall, Ingram and Nelson, Paul V. and Whipker, Brian E.}, year={2018}, month={Aug}, pages={288–294} }
 @article{zhang_truong_tanguay_reif_2017, title={A New Statistical Approach to Characterize Chemical-Elicited Behavioral Effects in High-Throughput Studies Using Zebrafish}, volume={12}, ISSN={["1932-6203"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85010006539&partnerID=MN8TOARS}, DOI={10.1371/journal.pone.0169408}, abstractNote={Zebrafish have become an important alternative model for characterizing chemical bioactivity, partly due to the efficiency at which systematic, high-dimensional data can be generated. However, these new data present analytical challenges associated with scale and diversity. We developed a novel, robust statistical approach to characterize chemical-elicited effects in behavioral data from high-throughput screening (HTS) of all 1,060 Toxicity Forecaster (ToxCast™) chemicals across 5 concentrations at 120 hours post-fertilization (hpf). Taking advantage of the immense scale of data for a global view, we show that this new approach reduces bias introduced by extreme values yet allows for diverse response patterns that confound the application of traditional statistics. We have also shown that, as a summary measure of response for local tests of chemical-associated behavioral effects, it achieves a significant reduction in coefficient of variation compared to many traditional statistical modeling methods. This effective increase in signal-to-noise ratio augments statistical power and is observed across experimental periods (light/dark conditions) that display varied distributional response patterns. Finally, we integrated results with data from concomitant developmental endpoint measurements to show that appropriate statistical handling of HTS behavioral data can add important biological context that informs mechanistic hypotheses.}, number={1}, journal={PLOS ONE}, author={Zhang, Guozhu and Truong, Lisa and Tanguay, Robert L. and Reif, David M.}, editor={Neuhauss, Stephan C.F.Editor}, year={2017}, month={Jan} }
 @article{barnes_nelson_hesterberg_shi_whipker_2017, title={Modeling impact of nitrogen carrier and concentration on root substrate pH}, volume={40}, ISSN={["1532-4087"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85029409669&partnerID=MN8TOARS}, DOI={10.1080/01904167.2016.1143502}, abstractNote={ABSTRACT We conducted an experiment to quantify the effects on substrate pH from nitrogen (N) carrier and concentration. We used four concentrations of N (3.5–14 mM) and five fractions of ammonium (NH4+) (0–80% NH4+ of total N) that are found in commercially available fertilizers. Fertilizers were applied to fallow 14-cm-diameter pots (1.29 L) filled with a 3 peat:1 perlite (v/v) substrate amended with non-residual powdered calcium carbonate to raise the substrate pH to approximately 6.0. Harvests occurred at 20 and 42 days. Significant effects in the model included main effects of N carrier and N concentration, their squared terms, an interaction effect, and a time × N carrier. The fraction of NH4+ accounted for 45.0% of variation in substrate pH, and N concentration accounted for 1.5% of the total R2 of 76.7%. Substrate acidification was likely due to the physiological fertilizer effect and nitrification.}, number={15}, journal={JOURNAL OF PLANT NUTRITION}, author={Barnes, Jared and Nelson, Paul V. and Hesterberg, Dean and Shi, Wei and Whipker, Brian E.}, year={2017}, pages={2101–2108} }
 @article{barnes_nelson_whipker_hesterberg_shi_2014, title={Fertilizer Formulation Effect on pH of Fallow Versus Planted Container Substrate}, volume={1034}, ISSN={["0567-7572"]}, DOI={10.17660/actahortic.2014.1034.57}, abstractNote={From previous work testing the impact of 30 fertilizers on substrate pH, five fertilizer formulations that elicited the widest range of substrate pH biotic impacts during Salvia farinacea ‘Evolution White’ cultivation were chosen for a follow up study to determine the abiotic impact of these fertilizers on fallow substrate. A 3 sphagnum peat moss : 1 perlite substrate was formulated and adjusted to pH 5.6. Three sets of pots (14 cm diameter) were filled with substrate. Salvia plugs were installed in the first set for cultivation while the second set was left fallow followed by fertilization of both sets with 400 mL of fertilizer solution with each irrigation (each at 7 mmol nitrogen concentration and pH 4.2 ± 0.1) to bring them to approximately container capacity. The third set of pots (control) was left fallow and irrigated with 400 mL deionized water instead of fertilizer solution. When cultivated substrates dried to approximately 50% of container capacity, 200 mL of fertilizer solution was applied to sets one and two and 200 mL deionized water to set three for a total of 11 applications. Substrates were harvested after 3 and 6 weeks. The pH of control substrate was 5.69 for both harvests. For the first and second harvest, cultivated substrate pH ranged from 6.08 to 5.03 and 6.22 to 4.85, respectively, while pH values of fallow substrate that received fertilizer solutions ranged from 5.66 to 5.19 and 5.44 to 4.97, respectively. Contrary to the expected abiotic effect of these acidic fertilizer solutions, pH in the fertilized fallow pots increased or decreased in a similar but diminished fashion to the changes that occurred to the pH in the cultivated pots. These results suggested a biotic effect in the fallow substrates due possibly to microflora and nitrification and indicate the need to take into account a biotic effect of microbes when assessing the abiotic effect of fertilizer solutions on substrate pH.}, journal={INTERNATIONAL SYMPOSIUM ON GROWING MEDIA AND SOILLESS CULTIVATION}, author={Barnes, J. and Nelson, P. and Whipker, B. E. and Hesterberg, D. and Shi, W.}, year={2014}, pages={465–469} }
 @article{barnes_nelson_fonteno_whipker_jeong_2013, title={Impact of Mature Dairy Manure Compost and Water Content on Wettability and Bulk Density in Peat Moss-Perlite Root Substrate}, volume={982}, ISSN={["2406-6168"]}, DOI={10.17660/actahortic.2013.982.7}, abstractNote={ISHS International Symposium on Responsible Peatland Management and Growing Media Production IMPACT OF MATURE DAIRY MANURE COMPOST AND WATER CONTENT ON WETTABILITY AND BULK DENSITY IN PEAT MOSS-PERLITE ROOT SUBSTRATE}, journal={INTERNATIONAL SYMPOSIUM ON RESPONSIBLE PEATLAND MANAGEMENT AND GROWING MEDIA PRODUCTION}, author={Barnes, J. and Nelson, P. and Fonteno, W. C. and Whipker, B. and Jeong, Ka-Yeon}, year={2013}, pages={75–80} }
 @book{nelson_2012, title={Greenhouse operation and management}, publisher={Boston: Prentice Hall}, author={Nelson, P. V.}, year={2012} }
 @article{ahmad_dole_nelson_2012, title={Nitrogen application rate, leaf position and age affect leaf nutrient status of five specialty cut flowers}, volume={142}, ISSN={["1879-1018"]}, DOI={10.1016/j.scienta.2012.04.009}, abstractNote={This study was conducted to determine the effect of nitrogen fertilizer levels on growth and yield of specialty cut flowers, ‘Chief’ celosia, ‘Sensation’ cosmos, ‘Sunbright’ and ‘Sunrich Orange’ sunflowers and ‘Benary Giant Mix’ zinnia, as well as record influence of leaf position and age on leaf nutrient concentrations. Plants grown in open field were supplied with five different N levels beginning five days after transplanting: no added N (control); one, two or three applications of N at 112 kg ha−1 at 40 day intervals; and a single application of 336 kg ha−1. Plants fertilized with two or three applications of 112 kg ha−1 produced the most flowers in celosia and all fertilizer applications increased yield equally in zinnia, but had no effect on cosmos and both cultivars of sunflower. Nitrogen fertilization produced the longest flower stems for cosmos and both sunflower cultivars, but had no effect on celosia and zinnia stem length. Nitrogen fertilization rate did not significantly affect days to harvest of all species tested. For leaf nutrient analysis, the upper one-third of the plant proved to be a reliable tissue source in all species. Generally, young leaf samples collected early in the season had higher nutrient concentrations as compared with the same leaf position at mid or late season. Increasing N fertilization increased N content of foliage for all species. Our recommended tissue nutrient levels were generally lower than those previously recommended for greenhouse-grown bedding plant cultivars of the same species.}, journal={SCIENTIA HORTICULTURAE}, author={Ahmad, Iftikhar and Dole, John M. and Nelson, Paul}, year={2012}, month={Jul}, pages={14–22} }
 @article{nelson_niedziela_pitchay_mingis_2010, title={EFFECTIVENESS, AMMONIUM IMPACT AND POTASSIUM ADEQUACY OF SOYBEAN-BASE LIQUID FERTILIZER ON BEDDING PLANTS}, volume={33}, ISSN={["0190-4167"]}, DOI={10.1080/01904160903575949}, abstractNote={A greenhouse study was conducted to compare the effectiveness of a soybean-base liquid fertilizer [Daniels Plant Food; 10 nitrogen (N):1.8 phosphorus (P): 2.5 potassium (K)] to two inorganic, greenhouse-type formulations containing 25 and 75% of nitrogen in the ammoniacal form on four bedding plant species (pansy, petunia, salvia, and vinca). Flowering was unaffected, foliage was deeper green, and substrate electrical conductivity was lower when fertilized with the soybean-base fertilizer. Plants were desirably more compact (lighter with less leaf area) when fertilized with the soybean-base and 75% ammoniacal fertilizer. While ammonium toxicity did not develop in any treatments at the standard lime rate, it occurred at low lime in all species with 75% ammoniacal and only lightly in pansy with soybean-base fertilizer, in spite of its 81% reduced nitrogen. Soybean fertilizer caused less acidification than 75% ammoniacal fertilizer. The potassium content of the soybean-base fertilizer was adequate to meet the requirements of the four species tested.}, number={5}, journal={JOURNAL OF PLANT NUTRITION}, author={Nelson, Paul V. and Niedziela, Carl E., Jr. and Pitchay, Dharmalingam S. and Mingis, Nancy C.}, year={2010}, pages={724–735} }
 @article{taylor_nelson_frantz_rufty_2010, title={PHOSPHORUS DEFICIENCY IN PELARGONIUM: EFFECTS ON NITRATE AND AMMONIUM UPTAKE AND ACIDITY GENERATION}, volume={33}, ISSN={["1532-4087"]}, DOI={10.1080/01904160903575923}, abstractNote={A sudden pH decline (SPD) of the substrate is an increasing problem in geranium growth systems, and the cause is unknown. In this study, we investigate whether a phosphorus (P) deficiency can cause SPD, and whether the effect is related to inhibition of ammonium (NH4 +) and nitrate (NO3 −) uptake and a corresponding shift in the cation to anion uptake balance. Geraniums (Pelargonium x hortorum Bailey ‘Designer Dark Red’) were grown in hydroponic solutions with or without P, and the hydroponics systems were located in a growth chamber programmed for light/dark temperatures of 22/18 or 26/22°C. Acidification potential was measured by the amount of base required to maintain pH at 5.8. The results indicated that much greater amounts of base were required to maintain a stable pH with P-limited plants. Using periodic exposures to 15NH4 + or 15NO3 −, it was found that NO3 − uptake was strongly inhibited as plants became P stressed. Tissue nutrient profiles showed that the NO3 − uptake inhibition was accompanied by an increase in the cation to anion uptake ratio. Rhizosphere acidification was greater at higher temperature even though the cation and anion responses were unchanged in control plants, suggesting the involvement of carbon dioxide (CO2) generated by root respiration. The results indicate that changes in cation and anion uptake and the associated increase in net H+ extrusion that occur under P-stress conditions can contribute to SPD in geranium culture systems.}, number={5}, journal={JOURNAL OF PLANT NUTRITION}, author={Taylor, Matthew D. and Nelson, Paul V. and Frantz, Jonathan M. and Rufty, Thomas W.}, year={2010}, pages={701–712} }
 @article{niedziela_kim_nelson_de hertogh_2008, title={Effects of N-P-K deficiency and temperature regime on the growth and development of Lilium longiflorum 'Nellie White' during bulb production under phytotron conditions}, volume={116}, DOI={10.1016/j.scienta.2008.02.01}, number={4}, journal={Scientia Horticulturae}, author={Niedziela, C. E. and Kim, S. H. and Nelson, P. V. and De Hertogh, A. A.}, year={2008}, pages={430–436} }
 @article{taylor_nelson_frantz_2008, title={Substrate acidification by geranium: Light effects and phosphorus uptake}, volume={133}, number={4}, journal={Journal of the American Society for Horticultural Science}, author={Taylor, M. D. and Nelson, P. V. and Frantz, J. M.}, year={2008}, pages={515–520} }
 @article{taylor_nelson_frantz_2008, title={Substrate acidification by geranium: Temperature effects}, volume={133}, number={4}, journal={Journal of the American Society for Horticultural Science}, author={Taylor, M. D. and Nelson, P. V. and Frantz, J. M.}, year={2008}, pages={508–514} }
 @article{rippy_nelson_2007, title={Cation exchange capacity and base saturation variation among Alberta, Canada, moss peats}, volume={42}, number={2}, journal={HortScience}, author={Rippy, J. F. M. and Nelson, P. V.}, year={2007}, pages={349–352} }
 @article{gibson_williams_whipker_nelson_dole_cleveland_walls_2007, title={Foliar symptomology and tissue concentrations of nutrient-deficient vegetative strawflower plants}, volume={38}, ISSN={["0010-3624"]}, DOI={10.1080/00103620701588379}, abstractNote={Abstract Elemental deficiencies of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper, zinc, or boron (N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, or B) were induced in plants of Florabella Pink strawflower [Bracteantha bracteata (Vent.) A. A. Anderberg]. Rooted stem cuttings were planted in 4.87‐L plastic containers and fertilized with a complete modified Hoagland's solution or this solution minus the element that was to be investigated. Plants were harvested for tissue analyses as well as dry weights when initial foliar symptoms were expressed and later under advanced deficiency symptoms. Deficiency symptoms for all treatments were observed within 7 weeks. The most dramatic expression of foliar symptoms occurred with N (chlorotic lower foliage leading to necrotic margins on the mature leaves), Ca (black necrotic spots on the tips of the young leaves), S (uniform chlorosis of young leaves and recently mature leaves), B (thick, leathery, and deformed young leaves), Fe (uniform yellowish‐green chlorosis on the young leaves), and Zn (brownish‐gray necrosis on the tips of the mature leaves). At the initial stage, only Fe‐deficient plants weighed less than the control, whereas K‐, Ca‐, and Mg‐deficient plants had greater dry weights than plants receiving the complete modified Hoagland's solution (control plants). Dry weights of plants treated with solutions not containing N, P, Ca, S, Cu, or Mn were significantly lower when compared with the control plants under an advanced deficiency. Foliar‐tissue concentration data will assist plant‐tissue analysis laboratories in establishing foliar symptom standards for growers.}, number={17-18}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Gibson, James L. and Williams, Amy and Whipker, Brian E. and Nelson, Paul V. and Dole, John M. and Cleveland, Brenda and Walls, F. R.}, year={2007}, pages={2279–2294} }
 @article{kim_niedziela_nelson_de hertogh_swallow_mingis_2007, title={Growth and development of Lilium longiflorum 'Nellie White' during bulb production under controlled environments - I. Effects of constant, variable and greenhouse day/night temperature regimes on scale and stem bulblets}, volume={112}, ISSN={["0304-4238"]}, DOI={10.1016/j.scienta.2006.11.015}, abstractNote={One-year-old scale and stem bulblets of Lilium longiflorum Thunb. ‘Nellie White’ (Easter lily) were grown under constant and variable growth chamber conditions and greenhouse conditions to compare growth and development and bulb production. Eight temperatures regimes were established using the following: six growth chambers set to provide day/night temperature regimes of 30/26, 26/22, 22/18, 18/14, 14/10 and 10/6 °C; a seventh growth chamber (VAR) programmed to begin at 22/18 °C, then decline in three 4–5 week steps to 10/6 °C, and subsequently increase in three 4–5 week steps to 22/18 °C to simulate seasonal field temperatures in the coastal bulb production area of northern California and southern Oregon; and a double layer polyethylene greenhouse (GH) set to begin cooling at 22 °C and heating at 18 °C. Ten percent of the scale bulblets and 35% of the stem bulblets failed to develop shoots (“no-shows”). “No-shows” increased with increasing temperature with a significant number starting at 18/14 °C. The moderately high GH temperature also induced “no-shows”. Maximum basal bulb (the main planted bulb) weight occurred at 26/22 °C for both bulblet types. Scale bulblets not only produced heavier basal bulbs with a larger circumference than stem bulblets, but also produced heavier stem bulbs. Stem bulb formation and production was maximized in the range of 18/14–26/22 °C and in the GH for scale bulblets. Stem bulb production from stem bulblets did not differ from zero. Scale bulblets produced more basal and stem roots than the stem bulblets at the end of the early growth period, but there was no significant difference at the end of the study. Root fresh weight was greatest in the range of 14/10–18/14 °C and declined at higher or lower temperatures. The VAR and GH treatments had similar root weights to those at 18/14 °C. Shoot length was maximized at 22/18 °C for stem bulblets and in the GH and at 22/18 °C for scale bulblets. Stem plus leaf (shoot) fresh weight was not statistically different between bulblet types with the exception of an increased weight for stem bulblets grown at 22/18 °C. Scale bulblets in the GH had greater stem plus leaf weights than scale bulblets in the other temperature regimes. Shoot leaf number was highest in stem bulblets at 22/18 °C and in the GH. In these two temperature treatments, more leaves were produced by stem bulblets than scale bulblets. In all other treatments, there was no significant difference in leaf number. Bulblet type had no effect on number of flowers produced. Flower number was maximum in the range 10/6–22/18 °C, decreased at 26/22 °C and in the GH, and was absent at 30/26 °C. For bulb production, reduced flowering is desired since flowers are generally removed during the outdoor bulb production period. Meristem abortion, which also causes a desirable reduction in flowers, was greater in scale bulblets. It occurred at 26/22 °C and was greater at 30/26 °C. Scale bulbs produced the largest main bulbs, with a maximum yield at 26/22 °C.}, number={1}, journal={SCIENTIA HORTICULTURAE}, author={Kim, S. H. and Niedziela, C. E., Jr. and Nelson, P. V. and De Hertogh, A. A. and Swallow, W. H. and Mingis, N. C.}, year={2007}, month={Mar}, pages={89–94} }
 @article{kim_niedziela_nelson_de hertogh_swallow_mingis_2007, title={Growth and development of Lilium longiflorum 'Nellie White' during bulb production under controlled environments - II. Effects of shifting day/night temperature regimes on scale bulblets}, volume={112}, ISSN={["0304-4238"]}, DOI={10.1016/j.scienta.2006.11.012}, abstractNote={One-year old scale bulblets of Lilium longiflorum Thunb. ‘Nellie White’ (Easter lily) were grown for 107 days during growth period 1 (GP-1) in six growth chambers under constant day/night temperature regimes of 30/26, 26/22, 22/18, 18/14, 14/10 and 10/6 °C. Subsequently, half of the plants in each temperature regime were transferred to 18/14 °C and the other half continued at the six constant temperature regimes. Both groups of plants were grown for an additional 89 days in growth period 2 (GP-2). Continuous temperatures of 26/22, 26/22–22/18 and 26/22–18/14 °C produced the greatest increase in basal bulb fresh weight (the main planted bulb), basal bulb circumference and stem bulb fresh weight, respectively. However, shifting these optimal temperatures to 18/14 °C during GP-2 resulted in a lower increase in basal bulb fresh weight and circumference. The optimum range for stem bulb production was expanded to 30/26–14/10 °C by shifting to 18/14 °C. The greatest increase for basal root growth occurred at 14/10–10/6 °C and for stem root growth at 14/10 °C. The temperature shift did not affect either root type. Maximum increase for stem length was at 26/22 and 22/18 °C and for stem plus leaf weight at 14/10 °C under constant temperature regimes. Transferring the plants from 10/6 to 18/14 °C resulted in the greatest increase in stem length and from 10/6 and 14/10 to 18/14 °C in the greatest increase in stem plus leaf weight. The greatest increase in the number of leaves occurred at 26/22 and 10/6 °C, but this growth parameter was unaffected by shifting to 18/14 °C, indicating that leaf number was determined in GP-1. Bulbils developed only when bulbs at high GP-1 temperature regimes (30/26 and 26/22 °C) were transferred to 18/14 °C during GP-2. Lower temperatures tended to favor an increase in flower bud production under continuous temperature regimes, while shifting to 18/14 °C increased flower bud production after initially high and low temperatures. Meristem abortion was greatest at 30/26 °C followed by 26/22 °C, but was not affected by temperature shifts in GP- 2. Thus, it is concluded that the abortion was induced or initiated during GP-1.}, number={1}, journal={SCIENTIA HORTICULTURAE}, author={Kim, S. H. and Niedziela, C. E., Jr. and Nelson, P. V. and De Hertogh, A. A. and Swallow, W. H. and Mingis, N. C.}, year={2007}, month={Mar}, pages={95–98} }
 @article{rippy_nelson_hesterberg_kamprath_2007, title={Reaction times of twenty limestones}, volume={38}, ISSN={["1532-2416"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34447308205&partnerID=MN8TOARS}, DOI={10.1080/00103620701435530}, abstractNote={Abstract Particle size and calcium carbonate equivalent characterize agricultural limestone. When agricultural limestone is used for horticultural container substrates, variations in pH among batches of substrate produced with the same limestone rate, as well as pH drift from initial pH, occur. Horticultural endeavors require more detailed characterization of limestone neutralization capacity than is provided for agricultural limestones. Reactivity of twenty limestones encompassing a broad range of calcium and magnesium carbonate were compared. Limestones were wet‐sieved into three particle‐diameter fractions and reacted with ammonium chloride in the presence of steam. Fine particles reacted faster than coarse; however, there was a point beyond which degree of fineness of calcitic limestone no longer affected reactivity. Dolomitic limestones were slower reacting than calcitic. Reactivity within particle fractions of dolomitic and coarse calcitic limestones varied significantly. These results indicate that particle diameter and calcium carbonate equivalent are not the only factors influencing limestone neutralization capacity.}, number={13-14}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Rippy, Janet F. M. and Nelson, Paul V. and Hesterberg, Dean L. and Kamprath, Eugene J.}, year={2007}, pages={1775–1783} }
 @article{rippy_nelson_2005, title={Soilless root substrate pH measurement technique for titration}, volume={40}, number={1}, journal={HortScience}, author={Rippy, J. F. M. and Nelson, P. V.}, year={2005}, pages={201–204} }
 @article{nelson_oh_cassel_2004, title={Changes in physical properties of coir dust substrates during crop production}, ISBN={["90-6605-537-5"]}, ISSN={["2406-6168"]}, DOI={10.17660/actahortic.2004.644.35}, number={644}, journal={PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON GROWING MEDIA & HYDROPONICS}, author={Nelson, PV and Oh, YM and Cassel, DK}, year={2004}, pages={261–268} }
 @article{peet_rippy_nelson_catignani_2004, title={Organic production of greenhouse tomatoes utilizing the bag system and soluble organic fertilizers}, volume={659}, ISBN={["90-6605-259-7"]}, ISSN={["0567-7572"]}, DOI={10.17660/actahortic.2004.659.92}, abstractNote={ISHS VII International Symposium on Protected Cultivation in Mild Winter Climates: Production, Pest Management and Global Competition ORGANIC PRODUCTION OF GREENHOUSE TOMATOES UTILIZING THE BAG SYSTEM AND SOLUBLE ORGANIC FERTILIZERS}, number={659}, journal={PROCEEDINGS OF THE VIITH INTERNATIONAL SYMPOSIUM ON PROTECTED CULTIVATION IN MILD WINTER CLIMATES: PRODUCTION, PEST MANAGEMENT AND GLOBAL COMPETITION, VOLS 1 AND 2}, author={Peet, MM and Rippy, JM and Nelson, PV and Catignani, GL}, year={2004}, pages={707–719} }
 @article{rippy_peet_louws_nelson_orr_sorensen_2004, title={Plant development and harvest yields of greenhouse tomatoes in six organic growing systems}, volume={39}, number={2}, journal={HortScience}, author={Rippy, J. F. M. and Peet, M. M. and Louws, F. J. and Nelson, P. V. and Orr, D. B. and Sorensen, K. A.}, year={2004}, pages={223–229} }
 @article{davis_sanders_nelson_lengnick_sperry_2003, title={Boron improves growth, yield, quality, and nutrient content of tomato}, volume={128}, number={3}, journal={Journal of the American Society for Horticultural Science}, author={Davis, J. M. and Sanders, D. C. and Nelson, P. V. and Lengnick, L. and Sperry, W. J.}, year={2003}, pages={441–446} }
 @article{nelson_kowalczyk_niedziela_mingis_swallow_2003, title={Effects of relative humidity, calcium supply, and forcing season on tulip calcium status during hydroponic forcing}, volume={98}, ISSN={["1879-1018"]}, DOI={10.1016/S0304-4238(03)00034-7}, abstractNote={Abstract The tulip ( Tulipa gesneriana L.) cultivars ‘Abra’, ‘Christmas Marvel’, ‘Golden Melody’, and ‘Jingle Bell’ were forced hydroponically during two early forcing periods (FPs) and ‘Golden Melody’ and ‘Oscar’ during two late FP. Treatments were factorial combinations of two relative humidity (RH) levels (42 and 82%) and five Ca(NO 3 ) 2 levels (0, 2.5, 5, 10, and 20 mM). The study was conducted in growth chambers at a constant 19 °C and a 14 h daylength in which 70 μmol s −1  m −2 PPF was provided by cool white florescent lamps. Calcium uptake and accumulation were less at 82% RH as compared to 42% RH; however, the incidence of Ca deficiency symptoms did not increase at the higher RH. A 2.5 mM Ca(NO 3 ) 2 solution prevented Ca deficiency symptoms in all cultivars except ‘Abra’ during all FP. Plants in FP4 (26 March–18April) weighed less and accumulated less Ca than the same cultivars in the earlier FP. Calcium uptake and transpiration were lower in distilled water and 20 mM Ca(NO 3 ) 2 than other Ca(NO 3 ) 2 treatments after day 22 in FP1 (22 December–26 January). Total Ca content was lower in the flowers of ‘Golden Melody’ tulips forced in distilled water than the Ca(NO 3 ) 2 treatments. Calcium dry weight (DW) concentration and total Ca content in the flowers of ‘Golden Melody’ tulips forced at 42% RH were higher than at 82% RH. Total Ca content in the flowers of ‘Golden Melody’ tulips decreased from FP3 to FP4.}, number={4}, journal={SCIENTIA HORTICULTURAE}, author={Nelson, PV and Kowalczyk, W and Niedziela, CE and Mingis, NC and Swallow, WH}, year={2003}, month={Sep}, pages={409–422} }
 @book{nelson_2003, title={Greenhouse operation and management (3rd ed.)}, ISBN={0130105775}, publisher={Upper Saddle River, NJ: Prentice Hall}, author={Nelson, P. V.}, year={2003} }
 @article{huang_nelson_bailey_fonteno_mingis_2002, title={Assessment of the need for nitrogen, phosphorus, potassium, and sulfur preplant nutrients for plug seedling growth}, volume={37}, number={3}, journal={HortScience}, author={Huang, J. S. and Nelson, P. V. and Bailey, D. A. and Fonteno, W. C. and Mingis, N. C.}, year={2002}, pages={529–533} }
 @article{scoggins_bailey_nelson_2002, title={Efficacy of the press extraction method for bedding plant plug nutrient monitoring}, volume={37}, number={1}, journal={HortScience}, author={Scoggins, H. L. and Bailey, D. A. and Nelson, P. V.}, year={2002}, pages={108–112} }
 @article{scoggins_bailey_nelson_2001, title={Development of the press extraction method for plug substrate analysis: Quantitative relationships between solution extraction techniques}, volume={36}, number={5}, journal={HortScience}, author={Scoggins, H. L. and Bailey, D. A. and Nelson, P. V.}, year={2001}, pages={918–921} }
 @article{huang_nelson_2001, title={Impact of pre-plant root substrate amendments on soilless substrate EC, pH, and nutrient availability}, volume={32}, ISSN={["0010-3624"]}, DOI={10.1081/CSS-120000968}, abstractNote={Pre-plant root substrate amendments have a great impact on the soluble salt level of plug seedling substrates. Nine common pre-plant amendments alone and a typical commercial combination of some of these showed that the greatest contributors to seedling substrate (2 sphagnum peat moss: 1 perlite: 1 vermiculite by volume) electrical conductivity (EC) level were gypsum, calcium nitrate, and potassium nitrate. Moderate contributions were realized from triple superphosphate, Epsom salt, and two commercial micronutrient mixes. The salt contributions from dolomitic limestone and wetting agent were small and of little commercial concern. At the most common application rates for seedling substrate, additions of gypsum, calcium nitrate, potassium nitrate, and the mixture raised the total substrate EC (saturated media extract procedure) by 1.47, 1.23, 1.09, and 1.57 dS m−1, respectively, from an initial no amendment level of 0.84 dS m−1. The resulting EC levels were unacceptable according to the current maximum standards. Seedling efficacy tests should be conducted with special attention paid to gypsum, calcium nitrate, and potassium nitrate for possible reduction or elimination from the pre-plant nutrient charge. During the 12 days following sowing, mean substrate EC for all amendments in the 0% leach treatment declined 19% while EC in the 20% leach treatment declined 36%. Of all the pre-plant amendments tested, the only single amendment that increased substrate pH over the control treatment was dolomitic limestone. All other amendments lowered substrate pH by 0.1 to 0.24 units when applied at standard commercial rates. When dolomitic limestone was incorporated in combination with other amendments in the mixture treatment, the substrate pH rise was not as great. The impacts of rate of nutrient amendments on nutrient availability are presented.}, number={17-18}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Huang, JS and Nelson, PV}, year={2001}, pages={2863–2875} }
 @article{huang_nelson_lee_2001, title={Seedling effect on root substrate pH}, volume={24}, ISSN={["0190-4167"]}, DOI={10.1081/PLN-100106972}, abstractNote={Paper used for seed germination tests may or may not contain limestone. The presence of limestone presented a pH buffer in this study that could interfere with studies addressing pH, calcium (Ca), or magnesium (Mg) effects on seedling development. Alternatively, pH of unbuffered chromatography paper was changed sufficiently by seedlings to confound research objectives that are pH dependent. Gradients across unbuffered substrate paper exceeded 1.5 pH units from a point under seedling roots to a distance 5 cm away. Precise measurements of effects of seedlings on substrate pH need to be taken in close proximity to the roots. Seedling effect on unlimed paper substrate pH varied across 25 taxa from a maximum rise of 1.4 units with zinnia to a decline of 1.1 units with tomato in the interim from sowing to separation of cotyledons. In general, pH levels in paper were higher when a basic complete nutrient solution with all nitrogen (N) in NO3 form was supplied compared to an acidic solution with N comprised of 40% NH4 + 60% NO3. In a peat moss:perlite substrate, 11 taxa altered substrate pH over a range of 0.6 units, much lower than on paper. While five taxa had similar pH enhancing or suppressing influences in the paper and peat moss: perlite substrates, six shifted the direction of the pH change. The effects of most taxa on pH were similar when fertilized with acidic or basic fertilizers. Exceptions included pansy (Viola x wittrockiana Gams.), petunia (Petunia x hybrida Vilm.-Andr.), snapdragon (Antirrhinum majus L.), and verbena (Veberna x hybrida Voss) that responded to basic fertilizer with higher substrate pH rises than anticipated. Only modest shifts occurred in the order of taxa in terms of their effects on substrate pH over time in the peat moss:perlite substrate. Taxa that tended to raise peat moss:perlite substrate pH regardless of fertilizer type or time included pansy, petunia, and vinca (Catharanthus roseus G. Don) while those that lowered pH were celosia (Celosia cristata L.), tomato (Lycopersicon esculentum Mill.), and zinnia (Zinnia elegans Jacq.).}, number={8}, journal={JOURNAL OF PLANT NUTRITION}, author={Huang, JS and Nelson, PV and Lee, JW}, year={2001}, pages={1133–1147} }
 @article{williams_nelson_hesterberg_2000, title={Phosphate and potassium retention and release during chrysanthemum production from precharged materials: I. Alumina}, volume={125}, number={6}, journal={Journal of the American Society for Horticultural Science}, author={Williams, K. A. and Nelson, P. V. and Hesterberg, D.}, year={2000}, pages={748–756} }
 @article{williams_nelson_2000, title={Phosphate and potassium retention and release during chrysanthemum production from precharged materials: II. Calcined clays and brick chips}, volume={125}, number={6}, journal={Journal of the American Society for Horticultural Science}, author={Williams, K. A. and Nelson, P. V.}, year={2000}, pages={757–764} }
 @article{oh_hesterberg_nelson_1999, title={Comparison of phosphate adsorption on clay minerals for soilless root media}, volume={30}, ISSN={["0010-3624"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0032961768&partnerID=MN8TOARS}, DOI={10.1080/00103629909370243}, abstractNote={Abstract The greenhouse industry aims to decrease phosphate discharge to help reduce eutrophication of surface waters, to reduce fertilizer consumption, and to maintain a more constant level of plant‐available phosphate. Iron and aluminum oxides and some aluminosilicate minerals are efficient sorbents for phosphate. The phosphate adsorption characteristics of synthetic hematite (α‐Fe2O3), goethite (α‐FeOOH), and allophane (Si3Al4O12 nH2O), and a commercial alumina (A12O3) were evaluated to determine their potential for reducing phosphate leaching from soilless root media. The pH dependence of phosphate adsorption and maximum adsorption capacities were determined by reacting each mineral with various levels of phosphate between pH 4.0 and 9.0 in a 10 mM potassium chloride (KCl) background solution. Adsorbed phosphate was determined by loss from solution. Adsorption envelopes (adsorbed phosphate versus pH) showed a decrease in phosphate adsorption with increasing pH, particularly for alumina and allophane, ...}, number={5-6}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Oh, YM and Hesterberg, DL and Nelson, PV}, year={1999}, pages={747–756} }
 @article{nelson_niedziela_1998, title={Effect of ancymidol in combination with temperature regime, calcium nitrate, and cultivar selection on calcium deficiency symptoms during hydroponic forcing of tulip}, volume={74}, ISSN={["1879-1018"]}, DOI={10.1016/S0304-4238(97)00158-1}, abstractNote={Experiments were conducted to determine the effect of ancymidol, as impacted by temperature, Ca(NO3)2, and cultivar, on the prevention of Ca deficiency symptoms during hydroponic forcing of tulip (Tulipa gesneriana L.). In all treatments where tulips were forced in distilled water, Ca deficiency symptoms occurred. Symptoms included scape topple; flower abortion; and chlorosis, water soaking, cracking, exudation, and purple pigmentation of the lower leaves. All symptoms except topple were avoided when tulips were forced in 5 mM Ca(NO3)2 solution. Topple was prevented by Ca(NO3)2 in a low temperature regime (21°C day–18°C night) in two of three experiments. Ca deficiency was not prevented in a high temperature regime (24°C day–21°C night). Plants forced in Ca(NO3)2 were too tall for commercial use. When forced in a solution of ancymidol, topple was prevented but all other symptoms of Ca deficiency persisted. An ancymidol rate of 0.25 mg per 650 ml pot containing five bulbs caused abortion, unrelated to Ca deficiency, in the cultivar Oscar. Forcing in a combination of 5 mM Ca(NO3)2 plus ancymidol prevented all symptoms of Ca deficiency in all experiments except in the high temperature regime of one. Ancymidol rates of 0.0625 and 0.125 mg per pot did not always provide adequate height control. A rate of 0.18 mg per pot in combination with 5 mM Ca(NO3)2 was sufficient to prevent Ca deficiency symptoms and provide adequate height control in all but one cultivar. `Jingle Bell' required an ancymidol rate of 0.24 mg for adequate height control. Prevention of topple by ancymidol did not appear to be due to the correction of Ca deficiency since ancymidol added to Ca(NO3)2 resulted in lower total Ca uptake per shoot. It was likely due to shorter, stronger scapes masking this Ca deficiency symptom.}, number={3}, journal={SCIENTIA HORTICULTURAE}, author={Nelson, PV and Niedziela, CE}, year={1998}, month={May}, pages={207–218} }
 @article{nelson_niedziela_1998, title={Effects of calcium source and temperature regime on calcium deficiency during hydroponic forcing of tulip}, volume={73}, ISSN={["1879-1018"]}, DOI={10.1016/S0304-4238(97)00157-X}, abstractNote={Tulips (Tulipa gesneriana L.) forced hydroponically in distilled water developed Ca deficiency symptoms, including topple and flower bud abortion. Prevention of Ca deficiency and uptake of Ca was greater when Ca was supplied in the NO3− form rather than as Cl− or SO42−. Calcium EDTA was injurious to plants at a concentration of 2.5 mM, a level too low to correct Ca deficiency. Addition of BO33−, K+, H2PO4−, or Hoagland's all nitrate solution with modified micronutrient levels to the Ca substrate failed to improve growth. The complete nutrient formulation reduced Ca uptake. Ca deficiency could not be prevented at the high temperature regime (22°C day–18°C night), due in part to suppress uptake of Ca. In the low temperature regime (18°C day–14°C night), a 5-mM solution of Ca(NO3)2 prevented Ca deficiency during all forcing periods. Similar results were obtained with a 7.5 mM solution of CaCl2.}, number={2-3}, journal={SCIENTIA HORTICULTURAE}, author={Nelson, PV and Niedziela, CE}, year={1998}, month={Mar}, pages={137–150} }
 @book{nelson_1998, title={Greenhouse operation and management}, ISBN={0133746879}, publisher={Upper Saddle River, NJ: Prentice Hall}, author={Nelson, P. V.}, year={1998} }
 @article{strojny_nelson_willits_1998, title={Pot soil air composition in conditions of high soil moisture and its influence on chrysanthemum growth}, volume={73}, ISSN={["0304-4238"]}, DOI={10.1016/S0304-4238(97)00156-8}, abstractNote={Chrysanthemums were grown in 15.2 cm standard pots in a heavy mix of clay loam soil+sphagnum peat moss (2:1). A fine texture mix was used to accentuate undesirable gas profiles in the soil. Soil air was analyzed at five depths in the soil profile. In one set of tests, water was applied to the top of the pot at a matrix potential in the center of the soil profile of −5 kPa. The average gas concentrations in soil air in the top and bottom fifths of soil were for O2—20.0 and 14.5%, for CO2—0.8 and 2.4%, and for C2H4—0 and 0.08 μl dm−3. Smooth concentration gradients of each gas occurred from top to bottom of the soil profile. The composition of soil air changed greatly during the drying cycle. At soil moisture tensions of −0.7, −2.5, and −5 kPa in the center of the soil profile, the gas concentrations in the lowest fifth of soil were for O2—9.6, 15.3, and 20.3%, and for CO2—4.5, 3.5, and 0.6%, respectively. Thus, soil atmospheric conditions for plant growth were poorest immediately after watering and continuously improved up to the time of watering. When pots of chrysanthemum were watered by capillary action from mats, the average concentration of gases in soil air in the lowest fifth of soil were 5.8% O2, 3.6% CO2, and 0.38 μl dm−3 C2H4. This gas profile was less desirable for growth than the profile found in top-watered pots. Unlike the situation in top-watered pots, the gas concentrations in mat-watered pots were stable. Roots in top-watered pots were restricted to the upper two thirds of the soil ball, and were distributed evenly in the inner part of the soil and at the periphery. Roots of mat-watered plants developed further down the vertical periphery of the pot than roots of top-watered plants, but they did not grow inside the ball. Chrysanthemum plants were grown through a hole in the side wall of each of five 3.9 cm tall by 15.2 cm diameter plastic rings stacked vertically and separated by stainless steel screens that allowed for passage of water but not roots. Water was applied to the top of these cylinder stacks. The largest plants developed in the top ring with progressively smaller plants at lower depths. Plants in the lower two rings developed interveinal chlorosis and did not reach commercial size.}, number={2-3}, journal={SCIENTIA HORTICULTURAE}, author={Strojny, Z and Nelson, PV and Willits, DH}, year={1998}, month={Mar}, pages={125–136} }
 @article{gislerod_nelson_1997, title={Effect of relative air humidity and irradiance on growth of Dendranthema x grandiflorum (Ramat.) Kitamura}, volume={62}, number={5}, journal={Gartenbauwissenschaft}, author={Gislerod, H. and Nelson, P. V.}, year={1997}, pages={214–218} }
 @article{williams_nelson_1997, title={Using precharged zeolite as a source of potassium and phosphate in a soilless container medium during potted chrysanthemum production}, volume={122}, number={5}, journal={Journal of the American Society for Horticultural Science}, author={Williams, K. A. and Nelson, P. V.}, year={1997}, pages={703–708} }
 @article{nelson_fonteno_1991, title={PHYSICAL ANALYSIS OF ROCKWOOL SLABS AND EFFECTS OF FIBER ORIENTATION, IRRIGATION FREQUENCY AND PROPAGATION TECHNIQUE ON CHRYSANTHEMUM PRODUCTION}, volume={14}, ISSN={["0190-4167"]}, DOI={10.1080/01904169109364247}, abstractNote={Abstract Chrysanthemum X morifolium ’Bright Yellow May Shoesmith’ was grown as a cut flower crop in rockwool slabs in various methods to test different cultural and rockwool options. Direct planting of unrooted and calloused cuttings led to deleterious water stresses in spite of a commercially prohibitive input of labor for syringing. Planting of partially rooted cuttings was successful in terms of flower production but required excessive labor. Satisfactory and equal results were obtained from 1) inserting cuttings rooted in rockwool cubes into the slab such that the cube top was either flush or 1.3 cm above the slab surface, 2) applying nutrients 1 or 3 times per day, and 3) a horizontal or verticle fiber orientation in the slab. Nutrient accumulation in plants of all treatments were in satisfactory ranges and did not account for observed differences in growth.}, number={8}, journal={JOURNAL OF PLANT NUTRITION}, author={NELSON, PV and FONTENO, WC}, year={1991}, pages={853–866} }
 @article{nelson_1990, title={DEVELOPING ROOT ZONE MANAGEMENT STRATEGIES TO MINIMIZE WATER AND FERTILIZER WASTE - THE UNITED-STATES PERSPECTIVE WITH EMPHASIS ON SURFACE APPLIED NON-RECIRCULATED SYSTEMS}, volume={272}, ISBN={["90-6605-234-1"]}, DOI={10.17660/actahortic.1990.272.25}, journal={SYMPOSIUM ON BEDDING AND POT PLANT CULTURE}, author={NELSON, PV}, year={1990}, pages={175–184} }
 @article{nelson_1984, title={Nutrition of forced tulips in greenhouse and hydroponic culture}, volume={28}, number={1}, journal={North Carolina Flower Growers' Bulletin}, author={Nelson, P. V.}, year={1984}, pages={8} }
 @article{nelson_elliott_mingis_1980, title={Sampling procedure for foliar analysis of Kalanchoe blossfeldiana 'Feuerzauber'}, volume={105}, number={4}, journal={Journal of the American Society for Horticultural Science}, author={Nelson, P. V. and Elliott, G. C. and Mingis, N. C.}, year={1980}, pages={599} }
 @article{nelson_krauskopf_mingis_1979, title={Minimum critical foliar levels of K, Mg, and B in Rieger elatior begonia}, volume={104}, number={6}, journal={Journal of the American Society for Horticultural Science}, author={Nelson, P. V. and Krauskopf, D. M. and Mingis, N. C.}, year={1979}, pages={793} }
 @article{nelson_krauskopf_mingis_1978, title={Nitrogen and potassium requirements of Rieger begonia (Begonia X hiemalis Fotsch)}, volume={103}, number={5}, journal={Journal of the American Society for Horticultural Science}, author={Nelson, P. V. and Krauskopf, D. M. and Mingis, N. C.}, year={1978}, pages={603} }
 @article{nelson_mingis_krauskopf_1976, title={Sampling procedure for foliar analysis of forcing azalea}, volume={11}, number={1}, journal={HortScience}, author={Nelson, P. V. and Mingis, N. C. and Krauskopf, D. M.}, year={1976}, pages={40} }
 @article{nelson_cover_1976, title={Varieties of fibrous begonia for a flowering plant crop}, volume={20}, number={1}, journal={North Carolina Flower Growers' Bulletin}, author={Nelson, P. V. and Cover, D.}, year={1976}, pages={1} }
 @article{nelson_bost_1975, title={Proper spacing for Rieger Elatior begonia}, volume={19}, number={1}, journal={North Carolina Flower Growers' Bulletin}, author={Nelson, P. V. and Bost, T.}, year={1975}, pages={2} }
 @article{nelson_krauskopf_mingis_1974, title={Foliar analysis of Rieger Elatior begonia: Sampling scheme and foliar standards}, journal={International Colloquium on Plant Analysis and Fertilizer Problems}, publisher={Hanover: German Society of Plant Nutrition}, author={Nelson, P. V. and Krauskopf, D. M. and Mingis, N.}, year={1974}, pages={343} }
 @article{nelson_1971, title={Copper deficiency in chrysanthemum: Critical level and symptoms}, volume={96}, number={5}, journal={Journal of the American Society for Horticultural Science}, author={Nelson, P. V.}, year={1971}, pages={661} }
 @article{nelson_1971, title={Symptoms and diagnosis of ammonium toxicity in chrysanthemum}, volume={15}, number={3}, journal={North Carolina Flower Growers' Bulletin}, author={Nelson, P. V.}, year={1971}, pages={2} }