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Kimberly A. Williams and Paul V. Nelson

Soilless container media have almost no capacity to retain PO4 or K. The nutrient retention of two calcined clays, attapulgite and arcillite, and brick chips, precharged with PO4 and K, was investigated. These could serve as an alternative slow-release fertilizer when incorporated into a soilless medium as a component of the mix. Sorption curves were developed at 25 °C for attapulgite of two particle sizes (0.8 to 1.6 mm and 1.6 to 3.2 mm), arcillite (1.1 to 3.2 mm), screened pieces of brick (1.0 to 3.6 mm), and a medium of 7 sphagnum peat: 3 perlite (v/v) using solutions of KH2PO4 (P at 0 to 20,000 mg.L-1). Curves indicated that PO4 and K sorption were similar for both particle sizes of attapulgite, so only the larger size [1.6 to 3.2 mm (8 to 16 mesh)] was used in greenhouse studies. Materials were evaluated in greenhouse studies by growing 'Sunny Mandalay' chrysanthemum [Dendranthema ×grandiflora Kitam. (syn. Chrysanthemum morifolium Ramat.)]. The precharged materials were tested at 10%, 20%, and 30% by volume of a peat: perlite root medium. Phosphate, K, and pH were determined on unaltered medium solutions collected throughout the cropping cycle and foliar analyses were determined on tissue collected at midcrop and end of the crop. Data indicated that precharged calcined clays retained and released PO4, and to some degree K, over time. Precharged clays did not provide K at levels which met plant needs during the latter half of the cropping cycle, but it was released and used at appreciable levels during the first month of crop production. Growth of plants receiving PO4 solely from precharged attapulgite and arcillite at 20% of the medium volume was not significantly different from that of a commercial control when the leaching fraction was maintained at 0.2. However, release of PO4 from the brick chips was not enough to match plant demand. Phosphate lost through leaching from the precharged clays was reduced by about two-thirds compared to control plants fertilized with P at 46.5 mg.L-1 from water-soluble fertilizer at each watering.

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Kimberly A. Williams and Paul V. Nelson

Most soilless container root media have limited ability to retain nutrients. Zeolites are minerals of substantial cation exchange capacity that can be precharged with K, and possibly PO4, and used as a component of soilless media as a slow-release nutrient source. A zeolite clinoptilolite (Cp) was charged with K and PO4 at two concentrations and combined at 20% of the mix with sphagnum peat (60%) and perlite (20%) to evaluate its use as the sole source of these nutrients during production of Dendranthema ×grandiflorum (Ramat.) Kitamura `Sunny Mandalay.' Phosphate, K, Na, and pH were determined on unaltered bulk root medium solutions collected over the course of production, and foliar analyses were determined on tissue collected at the middle and end of the crop. All leachate was collected and analyzed to allow for the creation of K and PO4 budgets. Plants that relied on precharged Cp at the low and high rates to meet their K needs and received a N/P/-K fertilizer had similar dry mass and tissue K concentrations as the control plants that received a complete fertilizer. The use of precharged Cp at the low rate reduced K losses through leaching to 23% of the amount lost from control plants receiving water-soluble fertilizer (WSF). Plants that relied on precharged Cp for their PO4 had a lower dry mass and tissue P levels than those of the complete control treatment. However, PO4 concentrations in the root medium solution were above acceptable levels during the first month of production and should be considered when developing a fertilizer application strategy using Cp precharged with PO4.

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Joshua K. Craver and Kimberly A. Williams

Student learning from producing crops in recirculating culture for a 6-week module in the Fall 2013 course HORT 570 Greenhouse Operations Management at Kansas State University was assessed. The module design followed Kolb’s experiential learning model, with teams of students responsible for production of lettuce (Lactuca sativa ‘Green Oak Leaf’) or basil (Ocimum basilicum ‘Italian Large Leaf’) and chives (Allium schoenoprasum ‘Purly’) crops in either a nutrient film technique (NFT) or in-pot recirculating culture system. Goals were to discern if this class experience would 1) improve student confidence and understanding of not only recirculating solution culture systems, but also general crop nutrient management; and 2) improve higher-order learning (HOL) skills of applying, analyzing, and evaluating information. Student learning was evaluated by administering the same survey, which included questions to evaluate student perception, lower-order learning (LOL), and HOL, at four separate times during the semester: 1) before mentioning plant nutrition, hydroponics, or recirculating solution culture; 2) after plant nutrition lectures but before the experiential module; 3) immediately upon completion of the experiential module; and 4) at the end of the semester. An increase in student confidence related to managing crop production in recirculating solution culture and nutrient management was perceived by students upon completion of the module. A significant increase in LOL occurred after the material was presented during the course lectures with an increase also occurring upon completion of the experiential module. In contrast, HOL did not significantly increase after the lecture material was presented, but significantly increased upon completion of the module. Both LOL and HOL was retained at the end of the semester. This evidence supports the role of experiential learning in improving student understanding and fostering HOL.

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Kimberly A. Williams and Paul V. Nelson

Seven organic materials including 1) the bacterium Brevibacterium lactofermentum (Okumura et al.) in a nonviable state, 2) a mixture of two bacteria, Bacillus licheniformis (Weigmann) and Bacillus subtilis (Ehrenberg), plus the fungus Aspergillus niger (van Tieghem) in a nonviable state, 3) an activated microbial sludge from waste-water treatment, 4) sludge from a poultry manure methane generator, 5) unsteamed bonemeal, 6) aged pine needles, and 7) poultry feathers were evaluated to determine their pattern and term of N release and the possibility of using them as an integral part of root media releasing N at a steady, low rate over 10 to 12 weeks for production of Dendranthema × grandiflorum (Ramat.) Kitamura `Sunny Mandalay'. These were compared to the inorganic slow-release fertilizer micro Osmocote (17N-3.9P-10.8K) and a weekly liquid fertilizer control. All organic sources released N most rapidly during the first 2 weeks, followed by a decline, which ended at 6 to 7 weeks. Brevibacterium lactofermentum, bonemeal, and micro Osmocote treatments resulted in about equal growth, which was similar to growth of a weekly liquid fertilizer control for 9 weeks in the first and for 12 weeks in the second experiment. The period of N release could not be extended through increased application rate of source due to the high initial release rate. It was not possible to lower source application rates to achieve an effective, low soil solution concentration due to the large variation in release rate over time. Efficiency of N use varied among plants grown in media treated with various microorganismal sources and was highest in those treated with B. lactofermentum. Nitrogen release from ground poultry feathers was inadequate, and additions of the viable hydrolyzing bacterium B. licheniformis to feathers failed to increase soil solution N levels. Attempts to retard mineralization of B. lactofermentum by cross-linking proteins contained within the bacterium by means of heat treatment at 116C vs. 82C failed. While anaerobic poultry manure sludge proved to be an inefficient source of N, it provided large amounts of P. Organic sources released primarily ammoniacal N, which raised the medium pH by as much as one unit, necessitating the use of less limestone in the medium formulation.

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Marci Spaw*, Kimberly A. Williams and Laura A. Brannon

This study compared student learning outcomes of two teaching methodologies: a summary lecture and an asynchronous web-based method that included a case study (www.hightunnels.org/planningcasestudy.htm) followed by an all-class discussion. Twenty-one students taking an upper-level undergraduate course in greenhouse management were randomly split into two groups. Each group experienced both methodologies with presentations designed to provide complimentary information about site planning for protected environment structures; however, the order in which the groups received the methods was reversed. After each presentation, the participants were given an identical quiz (Time 1 and Time 2) comprised of questions that assessed knowledge gained, higher-order learning, and their perception of how confident they would be in solving actual site planning scenarios. Though quiz scores were not different between the two groups after Time 1 or 2, overall quiz scores improved after Time 2 for both groups combined (P = 0.03). When questions were categorized as lower-order vs. higher-order learning, a greater increase in scores was observed in higher-order learning (P = 0.12 vs. P = 0.04, respectively). Although students' perceived confidence was not influenced by which method was received first (P = 0.23), their confidence increased after Time 2 compared to Time 1 (P = 0.07). Rather than one teaching method being superior to the other, this study suggests that it is beneficial to use both. Interestingly, while students overwhelmingly preferred to receive the summary lecture before the web-based method, there was no significant difference in test scores between the two orders, suggesting that neither order offered any advantage.

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Morgan M. Jenkins, Kimberly A. Williams and Laura A. Brannon

This research examines whether knowledge about floral preservatives increases consumers’ perception of quality, purchase intention, and price of a floral arrangement. A survey was administered to 222 participants at two locations in Manhattan, KS. Seventy-three percent of respondents fell within Generation Y (18 to 30 years old). The survey instrument presented four levels of presentation of a floral arrangement that were associated with increasing knowledge about the use of floral preservatives on consumers’ perceptions about the quality and price of that arrangement, as follows: Level 1 showed a photo of a floral arrangement without preservatives; Level 2 showed the same photo of a floral arrangement with a small, unlabeled packet of preservatives; Level 3 showed the same photo of a floral arrangement with a large, clearly labeled packet of preservatives; and Level 4 showed the same photos as Level 3 but was presented after a 191-word message describing the three functions of floral preservatives. Participants of the survey rated the quality of a floral arrangement higher from Level 2 (presence of floral preservatives not explicit) to Level 3 (presence of floral preservatives explicit) and from Level 3 to Level 4 (after reading a message about floral preservatives’ function and effectiveness). Their intent to purchase the floral arrangement generally increased with each level of presentation. Females indicated intention to purchase flowers more frequently than males. Participants increased the price that they were willing to pay for the floral arrangement at each level of presentation, starting at $25.46 at Level 1 (no floral preservatives use indicated) to $29.19 at Level 4. Participants were more knowledgeable about the benefits of floral preservatives and believed that floral preservatives increased the value of floral arrangements after reading a message describing their function and effectiveness more so than before reading a message. The younger the respondent, the more willing they were to pay more for floral arrangements with floral preservatives. As consumers become more aware of the use of floral preservatives and more knowledgeable about how and why they are effective, they attribute higher quality to floral arrangements with preservatives, they are willing to pay more for arrangements with preservatives, and their purchase intention frequency increases. Florists should always use preservatives in their processing and construction of fresh floral arrangements, consider providing a message about the function and effectiveness of floral preservatives to their customers, and then market their use of these materials.

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Rose A. Ogutu, Kimberly A. Williams and Gary M. Pierzynski

Calcined materials may contribute enhanced phosphate (PO4-P) retention to soilless root media used in container production. Properties of nutrient retention vary greatly depending on the parent clay and calcining treatment. This research characterized PO4-P sorption of various calcined clay products, including low and regular volatile material (LVM and RVM) 2:1 attapulgite, montmorillonite, and illite clays at various particle sizes; 1:1 kaolin clays in powder form; and diatomaceous earth. Extractable PO4-P, initial pH, PO4-P sorption isotherms, amount of P sorbed as a function of solution pH at a fixed total concentration, and degree of phosphorus saturation were determined. Initial pH of the clays ranged from 3.7 to 8.7. Sorption isotherms were conducted with initial adsorbate concentrations ranging from 0 to 200 mg·L−1 PO4-P from KH2PO4. The calcined materials varied in their ability to sorb PO4-P and generally yielded L-type isotherms, indicating that the adsorbate had relatively high affinity for the calcined material sample surface at low surface coverage. Some 2:1 calcined clays exhibited substantial PO4-P retention, but 1:1 calcined clays and diatomaceous earth did not. Clays with less moisture (LVM) resulted in greater PO4-P sorption than those calcined at lower temperatures (RVM). Terra Green montmorillonites had higher PO4-P sorption than Terra Green attapulgites. Laboratory results indicated potential for substantive PO4-P retention by several of the calcined clay materials when used in container production. For most materials, PO4-P sorption did not show pronounced pH dependence, which suggests that PO4-P retention is not influenced by pH-dependent charge within the pH range of container production.

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Kimberly A. Williams, Chad T. Miller and Ward Upham

In recent years, many horticulture departments around the United States have been concerned with recruiting and retaining an adequate number of students. One potential recruitment opportunity is the horticulture Future Farmers of America (FFA) Career Development Events (CDEs). For the time period of 1999 to 2012 (14 years), 1462 students participated in the annual state-level horticulture contests, comprising floriculture and nursery/landscape CDEs, held at Kansas State University (KSU). Using the rosters from these two CDEs, we referenced the university’s student information database to determine whether the high school students who participated as FFA horticulture CDE contestants ultimately matriculated to KSU. Fifty-two percent of former FFA horticulture CDE participants were accepted to KSU and 32% matriculated. Of these, 58% enrolled in the College of Agriculture and 19% majored in horticulture. Therefore, 3.5% of total horticulture CDE participants majored in horticulture at KSU. Students who participated in more than one horticulture CDE over time were more likely to major in horticulture at KSU compared with students who competed only once. Thirty-nine percent of students who participated in both horticulture CDEs pursued a baccalaureate program in horticulture. These two student characteristics could be used as indicator data points to target recruitment of future horticulture students. Data about the high school programs that generated contest participants were also summarized. Exceling in the CDE contests was not an indicator CDE participants would pursue a baccalaureate degree in horticulture. These analyses suggest FFA CDEs have some potential to optimize student recruitment efforts.

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Kimberly A. Williams, Paul V. Nelson and Dean Hesterberg

Soilless root media have little capacity to retain PO4 or K, and this contributes to leaching of these nutrients during greenhouse crop production. The objective of this research was to evaluate the suitability of precharged alumina as a sole source of PO4 and K during greenhouse production of potted chrysanthemum [Dendranthema ×grandiflora Kitam. (syn. Chrysanthemum ×morifolium Ramat.)]. Phosphate and K adsorption and desorption curves were created at 25 °C for two particle sizes (0.5 to 0.9 and 1.8 to 3.2 mm) of alumina (Al2O3; acid-washed and unwashed), and a medium of 7 peat: 3 perlite (v/v) using solutions of KH2 PO4 (P at 0 to 20,000 mg.L-1). Based on these curves, 1.8 to 3.2 mm, unwashed alumina was selected for use in the studies. Precharged alumina was tested in two greenhouse studies at 10% and 30% (v/v) of a peat-perlite medium used to produce `Sunny Mandalay' chrysanthemum. Phosphate, K, and pH were determined on unaltered root medium solutions collected throughout the 10-week cropping cycle, and foliar analyses were conducted on tissue collected at the middle and end of the cycle. Potassium release was adequate to meet chrysanthemum demand for 4 weeks, but inadequate for the remainder of the production cycle. Precharged alumina retained and released PO4 at sustained concentrations (P at <2 mg·L-1) over the course of a 10-week cropping cycle. Growth of plants receiving PO4 from precharged alumina was not significantly different from the controls receiving liquid fertilizer (P at 46.5 mg·L-1) at each watering when precharged alumina comprised 30% of the medium, and only slightly less when precharged alumina comprised 10% of the medium. A phosphorus budget showed that while 36% (103 mg) of the applied PO4-P was lost in the leachate of the controls, only 0.1% (2 mg) was lost from plants produced with alumina-P. This research demonstrates that in a soilless medium with physical properties similar to standard commercial mixes, low but adequate PO4 concentrations can be achieved and sustained using current production practices.

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Janet L. Carlino, Kimberly A. Williams and Earl R. Allen

Chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] growth and nutrient leaching of three clinoptilolite-based root media—NZ, EZ1, and EZ2—were compared to the performance of control plants grown in Sunshine Mix #2 [3 peat : 1 perlite (v/v)]. The control received 210 mg·L−1 N from an 18N-4P-15K soluble fertilizer at each irrigation. NZ contained untreated zeolite and received the same soluble fertilizer as the control but leached lower concentrations of NH4-N, K, and PO4-P during most of the production cycle compared to the control. EZ1 was formulated to provide N, P, and K as fertilizer nutrients and produced plants similar to the control based on ratings, height, width, and dry mass, but not fresh mass, at harvest when the fertilizer rate was half of that applied to the control—105 mg·L-1N. EZ2 did not receive P or K from soluble fertilizer and produced plants similar to the control based on rating, height, and dry mass, but not width or fresh mass, with soluble fertilizer input reduced to N alone. Tissue N, P, and K concentrations of plants grown in EZ1 and EZ2 were lower than those of control plants. With further refinements, these zeolitebased products show promise for decreasing nutrient leaching during crop production and allowing for application of lower rates of soluble fertilizers.