@article{veazie_cockson_smith_schulker_jackson_hicks_whipker_2025, title={Impact of substrate pH and micronutrient fertility rates on <i>Cannabis sativa</i>}, volume={8}, ISSN={["2639-6696"]}, DOI={10.1002/agg2.70044}, abstractNote={Abstract Micronutrient accumulation caused by low pH can lead to toxicity and have detrimental impacts on plant growth. In substrates with elevated pH, micronutrients become less available. In the first experiment, industrial hemp ( Cannabis sativa L.) growth was less at pH 3.0 and 4.0 than when pH was ≥5.0. Root growth was also observed to be inhibited at low pH levels. Leaf tissue micronutrient concentrations were higher at the lowest pH level, but no toxic accumulation occurred. In experiment 2, root growth had less mass at the lowest pH (3.1) and highest pH level (7.1). In experiment 3, substrates with three target pHs (3.8, 4.8, and 6.5) as well as three micronutrient concentrations (1X, 2X, and 4X) were examined to determine the impact of pH on micronutrient accumulation in two cultivars Cherry Wine (CW) and Sweetened (SW). Foliar micronutrient concentrations were the greatest in plants grown with pH 3.8, and the lowest concentrations occurred in plants grown at pH 6.5. Susceptibility to toxicity from micronutrient accumulation in plant tissue varied by cultivar. SW plants grown at pH 3.8 and 4X micronutrients resulted in lower leaf micronutrient toxicity symptoms, while CW plants grown under the same conditions did not. These studies suggest that C. sativa does not accumulate micronutrients to toxic levels at low pH when micros are applied within normal growing ranges, but that growth is inhibited at substrate pH < 5.0.}, number={1}, journal={AGROSYSTEMS GEOSCIENCES & ENVIRONMENT}, author={Veazie, Patrick and Cockson, Paul and Smith, J. Turner and Schulker, Brian and Jackson, Brian and Hicks, Kristin and Whipker, Brian}, year={2025}, month={Mar} }
 @article{schulker_jackson_2023, title={Impact of wood fiber substrate additions on water capture through surface and subsurface irrigation}, volume={1377}, ISSN={["2406-6168"]}, DOI={10.17660/ActaHortic.2023.1377.74}, journal={XXXI INTERNATIONAL HORTICULTURAL CONGRESS, IHC2022: INTERNATIONAL SYMPOSIUM ON INNOVATIVE TECHNOLOGIES AND PRODUCTION STRATEGIES FOR SUSTAINABLE CONTROLLED ENVIRONMENT HORTICULTURE}, author={Schulker, B. A. and Jackson, B. E.}, year={2023}, pages={597–603} }
 @article{schulker_jackson_fonteno_heitman_albano_2021, title={Exploring Substrate Water Capture in Common Greenhouse Substrates through Preconditioning and Irrigation Pulsing Techniques}, volume={11}, ISSN={["2073-4395"]}, DOI={10.3390/agronomy11071355}, abstractNote={Particles in a substrate create a network of pore pathways for water to move through, with size and shape determining the efficacy of these channels. Reduced particle size diversity can lead to increased leachate, poor substrate hydration, and an inefficient irrigation practice. This research examined the hydration characteristics of three greenhouse substrate components at three preconditioned initial moisture contents using subirrigation under five different irrigation durations and three water depths (2 mm, 20 mm, and 35 mm). Sphagnum peatmoss, coconut coir, and aged pine bark were tested at 67%, 50%, and 33% initial moisture (by weight). The objectives were to determine the impact of varying irrigation event durations (5, 10, 20, 30, 60 min) over a 60-min period, and the further influence of water depth and initial moisture, on the water capture abilities of peat, coir, and pine bark. The number of irrigation events depended on the irrigation event time of that experimental unit divided by the total time of 60 min, varying from 12, 6, 3, 2, and 1 event. Hydration efficiency was influenced by initial moisture content (IMC), water depth, pulsing duration, and inherent substrate characteristics (hydrophobicity/hydrophilicity). Initial MC had the largest impact on peat, regardless of water level or irrigation duration. Lower IMCs increased the hydrophobic response of peat, further reducing the amount of water the substrate was able to absorb. Pine bark had a 5–10% decrease in initial hydration between 67%, 50%, and 33% IMC, while coir’s hydrophilic nature reduced any IMC affects. At 50% IMC or less, coir had the highest volumetric water content (VWC) across all substrates, pulsing durations, and water depths. Water depth was found to increase initial hydration and final hydration 6–8% across all substrates. These three materials had altered and varied water capture responses depending on the combination of treatments employed. This work demonstrated the effects of intensity and exposure on substrates and the need for more integrated research for improving water use efficiency on container crops.}, number={7}, journal={AGRONOMY-BASEL}, author={Schulker, Brian A. and Jackson, Brian E. and Fonteno, William C. and Heitman, Joshua L. and Albano, Joseph P.}, year={2021}, month={Jul} }
 @article{schulker_jackson_fonteno_heitman_albano_2020, title={Comparison of Water Capture Efficiency through Two Irrigation Techniques of Three Common Greenhouse Soilless Substrate Components}, volume={10}, ISSN={["2073-4395"]}, DOI={10.3390/agronomy10091389}, abstractNote={Substrate wettability is an important factor in determining effective and efficient irrigation techniques for container-grown crops. Reduced substrate wettability can lead to lower substrate water capture, excessive leaching and poor plant growth. This research examined substrate water capture using surface and subirrigation under three initial moisture contents (IMC). Sphagnum peat moss, coconut coir, and pine bark were tested at IMCs of 67% 50%, and 33%. Substrate water capture was influenced by both IMC and irrigation technique. Surface irrigation increased the water capture of coir and peat, regardless of IMC, whereas IMC influenced pine bark water capture more than irrigation method. Surface-irrigated coir at or above 50% IMC provided the greatest water capture across all treatments. The first irrigation had the highest capture rate compared to all other events combined. Container capacities of pine bark and coir were unaffected by IMC and irrigation type, but the CC of peat was less by ~ 40% volumetrically under low IMC conditions. Coir, had the greatest ability to capture water, followed by pine bark and peat, respectively. Moisture content, irrigation type and component selection all influence the water capture efficiency of a container substrate.}, number={9}, journal={AGRONOMY-BASEL}, author={Schulker, Brian A. and Jackson, Brian E. and Fonteno, William C. and Heitman, Joshua L. and Albano, Joseph P.}, year={2020}, month={Sep} }