@article{veazie_chen_hicks_holley_eylands_mattson_boldt_brewer_lopez_whipker_2024, title={A Data-driven Approach for Generating Leaf Tissue Nutrient Interpretation Ranges for Greenhouse Lettuce}, volume={59}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI17582-23}, abstractNote={In the absence of controlled sufficiency studies, foliar interpretations for many horticultural crops are based on survey concentrations from small data sets. In addition, both survey and sufficiency ranges provide little interpretation regarding zones that are above or below the concentration range deemed “sufficient.” While providing a critical initial set of ranges, it was based on a limited set of data and therefore improvements in interpretation of data are needed. This study presents a novel method based on 1950 data points to create data-driven nutrient interpretation ranges by fitting models to provide more refined ranges of deficient (lowest 2.5%), low (2.5% to 25%), sufficient (25% to 75%), high (75% to 97.5%), and excessive (highest 2.5%). Data were analyzed by fitting Normal, Gamma, and Weibull distributions. Corresponding P values were calculated based on the Shapiro-Wilk test for normality for the Normal and Gamma distributions, and the Kolmogorov-Smirnov test was used for the Weibull distribution. The optimal distribution was selected based on the lowest Bayesian Information Criterion (BIC) value and visual fitness. The Weibull distribution best represented nitrogen, phosphorus, potassium, calcium, manganese, zinc, and copper, and the Gamma distribution best represented magnesium, sulfur, iron, and boron. Using the selected distributions, we propose a refined set of nutrient evaluation ranges for greenhouse-grown lettuce. These refined standards will aid growers and technical specialists in more accurately interpreting leaf tissue sample data.}, number={3}, journal={HORTSCIENCE}, author={Veazie, Patrick and Chen, Hsuan and Hicks, Kristin and Holley, Jake and Eylands, Nathan and Mattson, Neil and Boldt, Jennifer and Brewer, Devin and Lopez, Roberto and Whipker, Brian E.}, year={2024}, month={Mar}, pages={267–277} }
 @article{whipker_veazie_ballance_hicks_owen_rich_seltsam_cockson_2024, title={Coleus cultivars nutritional status as a function of leaf coloration}, ISSN={["1532-4087"]}, DOI={10.1080/01904167.2024.2325939}, journal={JOURNAL OF PLANT NUTRITION}, author={Whipker, Brian and Veazie, Patrick and Ballance, M. Seth and Hicks, Kristin and Owen, W. Garrett and Rich, W. Tyler and Seltsam, Lauren and Cockson, Paul}, year={2024}, month={Mar} }
 @article{veazie_jeong_jackson_suchoff_whipker_2024, title={Peat Substrates Amended with Wood-based Biochar Do Not Influence the Efficacy of Paclobutrazol Drenches}, volume={59}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI17621-23}, abstractNote={Various soilless substrate components have been evaluated for many years to identify sustainable resources that do not negatively impact plant growth. Biochar is a carbon-based material that has been evaluated for use as an alternative aggregate in peat-based soilless substrates. In addition, the use of carbon adsorption for compound removal is widely used in groundwater remediation, municipal water filtration, and volatile organic compounds. Experiment one aimed to determine the impact of coarse biochar (<6 mm) on paclobutrazol efficacy when incorporated at 15% or 30% by volume in a peat-based substrate when compared with a perlite-amended substrate at the same incorporation volumes. In Expt. 1, a single paclobutrazol drench application of 0, 0.5, 1.0, 2.0, and 4.0 mg·L −1 was applied to ‘Princettia Red’ and ‘Princettia White’ poinsettias ( Euphorbia pulcherrima × Euphorbia cornastra ). In Expt. 2, two different biochar particle sizes of coarse (<6 mm) and extra coarse (>6 mm) were examined at the same incorporation volumes as Expt. 1 and compared with a perlite-amended substrate at the same incorporation volumes. However, during Expt. 2, continual drench applications at times of irrigation of 0.0, 6.25, 12.5, 25.0, 50, and 100 μg·L −1 (ppb) paclobutrazol were applied to pansy ( Viola × wittrockiana ) ‘Matrix Blue Blotch’ and begonia ( Begonia × hybrida ) ‘Big Red Bronze Leaf’. The efficacy of paclobutrazol drenches for controlling growth in all species was unaffected by the substrate composition regarding aggregate type or aggregate incorporation rate. Thus, even though biochar is often used for bioremediation and wastewater treatment, it did not negatively impact the efficacy of paclobutrazol drenches at the concentrations used. This research suggests that when biochar is used as an amendment to peatmoss it will not influence paclobutrazol drench efficacy when incorporated up to 30% by volume for the examined species.}, number={2}, journal={HORTSCIENCE}, author={Veazie, Patrick and Jeong, Ka Yeon and Jackson, Brian and Suchoff, David and Whipker, Brian E.}, year={2024}, month={Feb}, pages={248–254} }
 @article{veazie_balance_whipker_jeong_2023, title={Comparison of Peat-Perlite-based and Peat-Biochar-based Substrates with Varying Rates of Calcium Silicate on Growth and Cannabinoid Production of <i>Cannabis sativa</i> 'BaOx'}, volume={58}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI17324-23}, abstractNote={Growers have been searching for alternative horticultural growing media components because of their desire to use sustainable resources. Biochar is a carbon-based material that has been evaluated for use as an alternative aggregate in peat-based soilless substrates. Additionally, silicon (Si) has been examined as a beneficial element to promote plant growth and plant quality in a variety of crops. However, there has been limited research regarding the interaction of biochar as an aggregate and Si in soilless substrates. This study aimed to determine the impact of Si and biochar on plant growth and nutrient uptake for greenhouse-cultivated hemp (Cannabis sativa L.). Hemp plants were grown in one of 12 different substrate blends: with two rates of calcium silicate (CaSiO3), two aggregate types of biochar (medium or coarse) or perlite, and aggregate percentages of 85% peat + 15% aggregate and 70% peat + 30% aggregate. The cannabinoid concentration, plant height, diameter, or total plant biomass were similar across all substrate blends after 12 weeks of growth. Additionally, the use of CaSiO3 as a Si substrate amendment increased Si foliar concentrations, and the addition of biochar to peat-based mixes did not limit the Si availability for plant uptake. However, Si substrate amendments did not impact plant height, diameter, or total plant biomass. This suggests that the biochar tested during this study is suitable in peat-based substrates for C. sativa ‘BaOx’ production at rates up to 30% (by volume) in peat-based substrates with CaSiO3 amendments.}, number={10}, journal={HORTSCIENCE}, author={Veazie, Patrick and Balance, M. Seth and Whipker, Brian E. and Jeong, Ka Yeon}, year={2023}, month={Oct}, pages={1250–1256} }
 @article{pandey_veazie_whipker_young_2023, title={Predicting foliar nutrient concentrations and nutrient deficiencies of hydroponic lettuce using hyperspectral imaging}, volume={230}, ISSN={["1537-5129"]}, DOI={10.1016/j.biosystemseng.2023.05.005}, abstractNote={Effective management of plant essential nutrients is necessary for hydroponically grown lettuce to achieve high yields and maintain production. This study investigated in situ hyperspectral imaging of hydroponic lettuce for predicting nutrient concentrations and identifying nutrient deficiencies for: nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), and sulphur (S). A greenhouse study was conducted using ‘Salanova Green’ lettuce grown with controlled solution treatments with varying macronutrient fertility rates of 0, 8, 16, 32, 64, and 100% each for N, P, K, Ca, Mg, and S. Plants were imaged using a hyperspectral line scanner at six and eight weeks after transplanting; then, plant tissues were sampled, and nutrient concentrations measured. Partial least squares regression (PLSR) models were developed to predict nutrient concentrations for each nutrient individually (PLS1) and for all six nutrient concentrations (PLS2). Several binary classification models were also developed to predict nutrient deficiencies. The PLS1 and PLS2 models predicted nutrient concentrations with Coefficient of Determination (R2) values from 0.60 to 0.88 for N, P, K, and S, while results for Ca and Mg yielded R2 values of 0.12–0.34, for both harvest dates. Similarly, plants deficient in N, P, K, and S were classified more accurately compared to plants deficient in Ca and Mg for both harvest dates, with F1 values (F-scores) ranging from 0.71 to 1.00, with the exception of K which had F1 scores of 0.40–0.67. Overall, results indicate that both leaf tissue nutrient concentration and nutrient deficiencies can be predicted using hyperspectral data collected for whole plants.}, journal={BIOSYSTEMS ENGINEERING}, author={Pandey, Piyush and Veazie, Patrick and Whipker, Brian and Young, Sierra}, year={2023}, month={Jun}, pages={458–469} }
 @article{henry_veazie_furman_vann_whipker_2023, title={Spectral Discrimination of Macronutrient Deficiencies in Greenhouse Grown Flue-Cured Tobacco}, volume={12}, ISSN={["2223-7747"]}, DOI={10.3390/plants12020280}, abstractNote={Remote sensing of nutrient disorders has become more common in recent years. Most research has considered one or two nutrient disorders and few studies have sought to distinguish among multiple macronutrient deficiencies. This study was conducted to provide a baseline spectral characterization of macronutrient deficiencies in flue-cured tobacco (Nicotiana tabacum L.). Reflectance measurements were obtained from greenhouse-grown nutrient-deficient plants at several stages of development. Feature selection methods including information entropy and first and second derivatives were used to identify wavelengths useful for discriminating among these deficiencies. Detected variability was primarily within wavelengths in the visible spectrum, while near-infrared and shortwave-infrared radiation contributed little to the observed variability. Principal component analysis was used to reduce data dimensionality and the selected components were used to develop linear discriminant analysis models to classify the symptoms. Classification models for young, intermediate, and mature plants had overall accuracies of 92%, 82%, and 75%, respectively, when using 10 principal components. Nitrogen, sulfur, and magnesium deficiencies exhibited greater classification accuracies, while phosphorus and potassium deficiencies demonstrated poor or inconsistent results. This study demonstrates that spectral analysis of flue-cured tobacco is a promising methodology to improve current scouting methods.}, number={2}, journal={PLANTS-BASEL}, author={Henry, Josh and Veazie, Patrick and Furman, Marschall and Vann, Matthew and Whipker, Brian}, year={2023}, month={Jan} }
 @article{veazie_ballance_whipker_2023, title={Supplemental lighting spectrum impact on sweet potato cutting production and rooting}, volume={9}, ISSN={["2374-3832"]}, DOI={10.1002/cft2.20202}, abstractNote={Abstract Light is an important factor in plant growth and morphology of sweet potato ( Ipomoea batatas L. Lam). This study explored the impact of supplemental lighting provided by three commercially available units on a stock plant cutting production and cutting rooting of two sweet potato cultivars ‘Covington’ and ‘Beauregard’. In experiment one, stock plants were grown under one of four lighting conditions, no supplemental light, high blue light emitting diode (LED), low blue LED, or halogen. Cuttings were collected twice a week for 5 wk and the total weekly cutting number and cutting caliper per plant were recorded. During this experiment plants grown under supplemental lighting exhibited significantly greater weekly total cutting numbers after 2 wk of growth when compared with those that were not exposed to supplemental lighting. In experiment two, cuttings were rooted under the same four light treatments and sampled on Days 7, 14, and 21 in which the cutting height, root weight, and shoot weight were recorded. On Day 21 Covington plants grown under low blue and halogen supplemental lighting exhibited significantly greater root dry weight when compared with those that did not receive supplemental lighting. However, no differences in rooting were observed for Beauregard. These results demonstrate that supplemental light increases stock plant growth regardless of the three commercially available light spectrums examined when compared with no supplemental light. This suggests that increasing the daily light integral (DLI) has a larger impact on plant growth than the spectrum of the commercially available lights that were examined.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, author={Veazie, Patrick and Ballance, M. Seth and Whipker, Brian}, year={2023}, month={Jun} }
 @article{veazie_jeong_ballance_whipker_2023, title={The Use of Silicon Substrate Amendments to Decrease Micronutrient Concentrations at Varying Micronutrient Fertility Rates with Cannabis sativa 'Auto CBG'}, volume={58}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI17162-23}, abstractNote={Many abiotic factors impact the yield and growth of Cannabis sativa (cannabis). Cannabis has been reported to be a bio-accumulator of heavy metals. For growers who are targeting floral production and other byproducts for human consumption, this is a concern. Silicon (Si) has been examined as a beneficial plant element to limit the uptake of heavy metals in a variety of crops. The objective of this study was to determine the impact of Si on heavy metal micronutrient uptake and plant growth for greenhouse-cultivated cannabis at varying Si substrate amendments. ‘Auto CBG’ plants were grown in a 70:30 peat:perlite substrate with one of three varying calcium silicate (CaSiO3) (Si) substrate amendment rates, Si0X, Si0.5X, or Si1X (of 0.0, 1.04, and 2.07 kg⋅m−3 CaSiO3), and one of three micronutrient fertility treatments, M1X [0.49 boron (B), 0.19 copper (Cu), 4.02 iron (Fe), 0.99 manganese (Mn), 0.01 molybdenum (Mo), and 0.20 zinc (Zn) mg⋅L−1], M2X, or M4X, using a modified Hoagland’s solution, creating a 3 × 3 factorial. Plants grown with a Si1X substrate amendment exhibited a significantly lower iron concentration in the foliage and root tissue when compared with those grown in a substrate without Si. After 6 weeks of growth, Si0X plants that received a M4X fertility rate exhibited greater foliar micronutrient concentrations of B, Mn, Zn, Fe, and Cu than plants that received a Si substrate amendment when provided a M4X fertility rate. Additionally, lower micronutrient concentrations in floral tissue were observed in plants that received a Si substrate amendment for M2X and M4X when compared with plants that did not. Silicon substrate amendments had no impact on the cannabinoid concentration or plant growth metrics after 12 weeks of growth. This research suggests that using a Si substrate amendment in a greenhouse production system can limit excessive uptake and accumulation of micronutrients in the foliage, roots, and floral material of cannabis without negative impacts on plant growth or cannabinoid concentrations.}, number={7}, journal={HORTSCIENCE}, author={Veazie, Patrick and Jeong, Ka Yeon and Ballance, M. Seth and Whipker, Brian E.}, year={2023}, month={Jul}, pages={797–803} }
 @article{veazie_pandey_young_ballance_hicks_whipker_2022, title={Impact of Macronutrient Fertility on Mineral Uptake and Growth of Lactuca sativa 'Salanova Green' in a Hydroponic System}, volume={8}, ISSN={["2311-7524"]}, url={https://doi.org/10.3390/horticulturae8111075}, DOI={10.3390/horticulturae8111075}, abstractNote={Lactuca sativa (commonly referred to as lettuce) is one of the most popular grown hydroponic crops. While other fertilizer rate work has been conducted on lettuce, the impact of each element has not been evaluated independently or by determining adequate foliar tissue concentrations when all nutrients are plant-available. This study explores the impact that macronutrients have on the growth and yield of lettuce at different stages of the production cycle. Additionally, this study explores the adequate nutrient rates by regressing nutrient curves to find the concentration of each element that corresponds to optimal growth. Plants were grown under varying macronutrient concentrations (0, 8, 16, 32, 64, and 100%) utilizing the concentrations of a modified Hoagland’s solution based on 150 mg·L−1 N. Lettuce plants were grown in a silica sand culture and received a nutrient solution in which a single element was altered. Visual symptomology was documented, and leaf tissue mineral nutrient concentrations and biomass were measured at Weeks 3, 6, and 8 after transplant. Optimal elemental leaf tissue concentration and biomass varied by macronutrient rates and weeks of growth. Nitrogen rate produced a linear increase in total plant dry weight, but foliar N followed a quadratic plateau pattern. Other elements, such as phosphorus, potassium, and magnesium, produced distinct total plant dry weight plateaus despite increasing fertility concentrations. These results demonstrate that fertility recommendation can be lowered for nutrients where higher rates do not result in higher plant biomass or foliar nutrient concentrations.}, number={11}, journal={HORTICULTURAE}, author={Veazie, Patrick and Pandey, Piyush and Young, Sierra and Ballance, M. Seth and Hicks, Kristin and Whipker, Brian}, year={2022}, month={Nov} }
 @article{cockson_veazie_davis_barajas_post_crozier_leon_patterson_whipker_2021, title={The Impacts of Micronutrient Fertility on the Mineral Uptake and Growth of Brassica carinata}, volume={11}, ISBN={2077-0472}, url={https://doi.org/10.3390/agriculture11030221}, DOI={10.3390/agriculture11030221}, abstractNote={Many abiotic factors impact the yield and growth of Brassica carinata (commonly referred to as carinata or Ethiopian mustard). Very little is known about carinata and how mineral nutrients impact its growth, and more specifically, the sufficiency values for fertility over the plant’s growth cycle and life stages. This study explored the impacts that plant nutrients, specifically micronutrients, can have on the growth and development of carinata over its distinct life stages (rosette, bolting, flowering, and pod set). Plants were grown under varying micronutrient concentrations (0, 25, 50, 75, 87.5, and 100%) of a modified Hoagland’s solution. Data were collected on plant height, canopy diameter, leaf tissue mineral nutrient concentrations, and biomass. The results demonstrated that micronutrient fertility has profound impacts on the production of Brassica carinata during different life stages. Boron (B) exclusion had the greatest impact on the growth and reproduction of Brassica carinata, with the death of the apical meristem that resulted in a lack of siliques or seeds at the lowest rate. Optimal relative elemental leaf tissue concentrations varied among micronutrient fertility concentrations and life stages. Certain elements exhibited linear increases in nutrient leaf tissue accumulation as solution concentration increased without reaching a maximum concentration during specific life stages. Other life stages and/or elements produced distinct plateau leaf tissue mineral concentrations despite increasing fertility treatment concentrations such as B in the rosette stage (47.2–50.0 mg·kg−1), copper (Cu) (bolting stage at 6.62–7.57 mg·kg−1), zinc (Zn) (bolting stage at 27.47–39.87 and flowering at 33.98–43.50 mg·kg−1), molybdenum (Mo) (flowering stage at 2.42–3.23 mg·kg−1), and manganese (Mn) (bolting stage at 117.03–161.63 mg·kg−1). This work demonstrates that Brassica carinata has different fertility demands and will accumulate differing leaf tissue concentrations during its life stages. This work serves as a baseline for further uptake and portioning work for Brassica carinata.}, number={3}, journal={AGRICULTURE-BASEL}, publisher={MDPI AG}, author={Cockson, Paul and Veazie, Patrick and Davis, Matthew and Barajas, Gabby and Post, Angela and Crozier, Carl R. and Leon, Ramon G. and Patterson, Robert and Whipker, Brian E.}, year={2021}, month={Mar}, pages={221} }
 @article{cockson_schroeder-moreno_veazie_barajas_logan_davis_whipker_2020, title={Impact of Phosphorus on Cannabis sativa Reproduction, Cannabinoids, and Terpenes}, volume={10}, ISSN={["2076-3417"]}, DOI={10.3390/app10217875}, abstractNote={Many abiotic factors, such as mineral nutrients—including phosphorus (P)—fertility, can impact the yield and growth of Cannabis sativa. Given the economic portion of C. sativa is the inflorescence, the restriction of P fertility could impact floral development and quality could be detrimental. This study sought to track the impacts of varying P concentrations (3.75, 7.50, 11.25, 15.0, 22.50, and 30.0 mg·L−1) utilizing a modified Hoagland’s solution. This experiment examined plant height, diameter, leaf tissue mineral nutrient concentrations, and final fresh flower bud weight as well as floral quality metrics, such as cannabinoids and terpenes. The results demonstrated that during different life stages (vegetative, pre-flowering, flowering), P concentrations impact C. sativa growth and development and yield. Regarding the cannabinoid pools, results varied for the individual cannabinoid types. For the acid pools, increasing fertility concentrations above 11.25 mg·L−1 P did not result in any increase in cannabinoid concentrations. These results indicate that, if a crop is being produced under greenhouse conditions, specifically for cannabinoid production, an excessive P supply did not result in higher cannabinoid production. However, plants grown with a higher rate of P fertility (30.0 mg·L−1) had greater plant width and may result in more buds per plant.}, number={21}, journal={APPLIED SCIENCES-BASEL}, author={Cockson, Paul and Schroeder-Moreno, Michelle and Veazie, Patrick and Barajas, Gabby and Logan, David and Davis, Matthew and Whipker, Brian E.}, year={2020}, month={Nov} }