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Samuel E. Wortman, Michael S. Douglass, and Jeffrey D. Kindhart

Demand for local food, including strawberries (Fragaria ×ananassa), is increasing throughout the United States. Strawberry production in the midwestern United States can be challenging due to the relatively short growing season and pests. However, vertical, hydroponic, high tunnel production systems could extend the growing season, minimize pest incidence, and maximize strawberry yield and profitability. The objectives of this study were to 1) identify the best cultivars and growing media for vertical, hydroponic, high tunnel production of strawberries in the midwestern United States and to 2) assess potential strategies for replacing synthetic fertilizer with organic nutrient sources in hydroponic strawberry production. To accomplish these objectives, three experiments were conducted across 2 years and two locations in Illinois to compare 11 strawberry cultivars, three soilless media mixtures, and three nutrient sources. Strawberry yield was greatest when grown in perlite mixed with coco coir or vermiculite and fertilized with a synthetic nutrient source. Yield was reduced by up to 15% when fertilized with a bio-based, liquid nutrient source and vermicompost mixed with soilless media. Strawberry yield among cultivars varied by year and location, but Florida Radiance, Monterey, Evie 2, Portola, and Seascape were among the highest-yielding cultivars in at least one site-year. Results contribute to the development of best management practices for vertical, hydroponic, high tunnel strawberry production in the midwestern United States, but further research is needed to understand nutrient dynamics and crop physiological response among levels within vertical, hydroponic towers.

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G.D. Hoyt, J.E. Walgenbach, and P.B. Shoemaker

This experiment was designed to compare best management practices for conventional and conservation tillage systems, chemical IPM vs. organic vegetable production, and rotation effect on tomatoes. Three vegetables were grown under these management practices with sweet corn (1st year) and fall cabbage or cucumber (2nd year), and fall cabbage on half of the field plots and tomatoes on the other half. The treatments were: 1) conventional-tillage with chemical-based IPM; 2) conventional-tillage with organic-based IPM; 3) conservation-tillage with chemical-based IPM; 4) conservation-tillage with organic-based IPM; and 5) conventional-tillage with no fertilizer or pest management (control). This poster describes sweet corn, cabbage, and cucumber yields from the various treatments over two 3-year rotations. Sweet corn yields were 34% higher in treatments with chemical fertilizer and pest control than with organic methods. Ear worm damage was high (58%) in the organic treatment compared to the chemical IPM program (14%). Fall cabbage was planted after sweet corn and cucumber harvest (all treatments were reapplied). Marketable cabbage yields were in the order: conventional-tilled-organic > strip-tilled-chemical > conventional-tilled-chemical > strip-till-organic > control for both years. Percent culls (< .9 kg heads) were in reverse order of marketable heads. Cabbage insect control was similar in chemical IPM and organic management. Cucumber yields were in the order: conventional-tilled-chemical > conventional-tilled-organic = strip-till-chemical > strip-tilled-organic > control for both years. Insect damage on cucumber fruit was 51% for organic systems and 1% for chemical methods of production. No differences were seen between tillage system within the same production system (chemical vs organic).

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T.L. Weinert, S.A. White, T.L. Thompson, and M.A. Maurer

Citrus production in the southwestern U.S. is highly dependent on inputs of irrigation and N fertilizer to achieve optimum fruit yield and quality. Microsprinkler irrigation may allow for substantial increase in efficiency of N and water application. However, best management practices have not yet been developed for microsprinkler use, particularly on newly established citrus trees. Experiments were conducted during 1997–98 in central Arizona to evaluate the effects of various N rates and fertigation frequencies on growth and N partitioning in young `Newhall' navel oranges planted in Apr. 1997. Two experiments were conducted, each with factorial combinations of N rate and fertigation frequency. In one experiment, non-labeled N fertilizer was used and in the other 15N-labeled N fertilizer. Trunk diameter, leaf N, and 15N partitioning in the trees were measured. During 1997, neither trunk diameter or leaf N were affected by N rate or fertigation frequency. No more than 6% of the N applied was taken up by the trees, and about 50% of the fertilizer N taken up was found in the leaves. Trees grew much more rapidly in 1998. Leaf N in fertilized plots was significantly higher than in control plots, but leaf N in all trees remained above the critical level of 2.5%. Despite rapid tree growth during 1998, no more than 25% of the fertilizer N applied was taken up by the trees. About 60% of the fertilizer N taken up was found in the leaves. Results suggest that N applications are not needed during the first growing season after planting for microsprinkler-irrigated citrus trees in the Southwest. Only modest rates (68 to 136 g/tree) will be needed during the second season to maintain adequate tree reserves.

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Eric Simonne, D. Studstill, M. Dukes, G. Hochmuth, R. Hochmuth, F. Roka, J. O'Hallorans, and A. Gazula

The development of best management practices (BMP) and the alloca-tion of pollution among land users in a watershed (TMDL) requires an understanding of the effect of cultural practices on both yields and nutrient leaching below the root zone. `Florida 47' tomato and `La Estrella' tropical pumpkin were grown on plasticulture using combinations of UF–IFAS recommended N and irrigation rates in a 1-ha field in 2004. Average N and irrigation rates over the whole field were 100% and 80%, respectively. Nitrate movement was assessed with twenty-four 1-m-long drainage lysimeters in each plot and ten 7-m-deep wells in and around the field Lysimeters and wells were sampled every 2 and 3 weeks throughout the year, respectively. Leachate volume and concentration in the drainage lysimeters were highly variable. Except shortly after the 25-cm rain due to hurricane Jeanne, most leachate volumes were <1 L·m–1. Annual NO3-N mean treatment load ranged between 7 and 15 kg·ha–1, but these differences were not significant due to high variability (CV = 175%). Single-lysimeter annual highest load was 39 kg·ha–1 of NO3-N (17.5% of N applied). In 2004, NO3-N concentration in well water was <1, ranged between 15 and 35, ranged between 0 and 10 mg·L–1 NO3-N in the up-stream control, inside, and perimeter wells, respectively. These concentrations are in the same ranges as those observed in this field in previous years (1997–2003) and often exceeded the 10 mg/L drinking water standard. Because NO3-N discharge into the environment may occur after the growing season, BMPs should be implemented on a year round basis. The methodology used in load measurement should be improved to better account for spatial variability.

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Monica Ozores-Hampton, Eric Simonne, Eugene McAvoy, Phil Stansly, Sanjay Shukla, Fritz Roka, Tom Obreza, Kent Cushman, Phyllis Gilreath, and Darrin Parmenter

Florida tomato growers generate about $600 million of annual farm gate sales. The Florida Vegetable and Agronomic Crop Water Quality/Quantity Best Management Practices Manual was adopted by rule in the Florida Administrative Code in 2006 and describes cultural practices available to tomato growers that have the potential to improve water quality. By definition, BMPs are specific cultural practices that are proven to optimize yield while minimizing pollution. BMPs must be technically feasible, economically viable, socially acceptable, and based on sound science. The BMP manual for vegetables endorses UF-IFAS recommendations, including those for fertilization and irrigation. Current statewide N fertilizer recommendations for tomato provide for a base rate of 224 kg/ha plus provisions for supplemental fertilizer applications 1) after a leaching rain, 2) under extended harvest season, and 3) when plant nutrient levels (leaf or petiole) fall below the sufficiency range. An on-farm project in seven commercial fields was conducted in 2004 under cool and dry growing conditions, to compare grower practices (ranging from 264 to 468 kg/ha of N) to the recommended rate. Early and total extra-large yields tended to be higher with growers' rate than with the recommended rate, but these differences were significant only in one trial. The first-year results illustrated the need for recommendations to be tested for several years and to provide flexibility to account for the reality of local growing conditions. Working one-on-one with commercial growers provided an opportunity to focus on each farm`s educational needs and to identify specific improvements in nutrient and irrigation management.

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Thomas A. Obreza and Robert E. Rouse

Controlled-release N (CRN) fertilizer is receiving interest as a possible nutrient best management practice (BMP) for Florida citrus production, but grower acceptance will be limited until cost decreases and familiarity with CRN materials increases. The objective of this study was to compare long-term citrus production resulting from N fertilizer programs containing isobutylidene diurea (IBDU) or methylene urea (MU) with a conventional water-soluble N fertilizer program to determine the magnitude of horticultural utility provided by CRN. We applied N to a newly planted `Hamlin' orange (Citrus sinensis L. Osbeck) orchard using three sources (100% ammonium nitrate (AN); a 50/50 mixture of AN/IBDU; a 60/40 mixture of AN/MU) at four rates (0.25, 0.5, 1.0, and 2.0 or 1.5 times the recommended annual rate) in factorial combination, and continued for 7 years. During this period, AN was applied 31 times vs. about 15 times for CRN-containing fertilizers. We measured fruit yield, juice quality, and total soluble solids (TSS) yield in years 4 through 7 and found that they generally were not affected by N source, especially when year-to-year variation was taken into account. In year 7, fruit and TSS yields of well-fertilized trees reached 153 and 9.2 kg/tree, respectively. Maximum 4-year cumulative fruit and TSS yields (486 and 27.6 kg/tree, respectively) occurred at an N rate of 200 kg/ha. Maximum juice quality occurred at 180 kg N/ha. We feel the CRN materials tested could be used successfully in a nutritional BMP program that would maintain high yields while potentially decreasing N loss to the environment.

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Chad Hutchinson* and Eric Simonne

Potato (Solanum tuberosum L.) production best management practices (BMPs) are under development for the Tri-County Agricultural Area (TCAA; St. Johns, Putnam, and Flagler counties) near Hastings, Fla. BMPs are designed to reduce nitrate non-point pollution in the St. Johns River from the |8000 ha in potato production in the TCAA. Research to develop a controlled release fertilizer (CRF) program to help growers meet the current nitrogen rate BMPs was conducted during the 2003 season. A randomized complete block experiment with four replications was conducted at the Plant Science Research and Education Unit in Hastings, Fla. The treatments were no nitrogen control, ammonium nitrate (168 and 212 kg N/ha) and three CRF products blended at different ratios (168 kg N/ha). Total tuber yields for `Atlantic' for the no nitrogen, and 168 and 212 kg N/ha ammonium nitrate treatments were 11.5, 23.4, and 36.4 MT/ha. The best combination of the three CRF products were a ratio of 33:33:33 with a 40 day, 75 day, 120 day release period, respectively. Total yield for this blend was 42.2 MT/ha. Specific gravities for tubers in all four treatments were 1.060, 1.072, 1.078, and 1.082, respectively. Percent of tubers with hollow heart four all four treatment were 8.1, 18.2, 20.0, and 6.4% respectively. Percent of tubers with internal heat necrosis four all four treatments were 20.6, 8.1, 20.6, and 6.3%, respectively. The CRF treatment produced significantly more tubers than the ammonium nitrate treatment at the same nitrogen rate. Quality of the tubers in the CRF treatment was higher than tubers from the no nitrogen control and ammonium nitrate treatments. Research will continue to optimize the CRF program for potato production in Florida.

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Travis C. Teuton, John C. Sorochan, Christopher L. Main, and Thomas C. Mueller

The transition zone is one of the hardest places to maintain high-quality turfgrasses, and the overall research objective was to determine best management practices to establish new turf cultivars in this zone. Hybrid bluegrasses (P. arachnifera Torr. × P. pratensis L.) have been bred for heat and drought tolerance and may offer a new alternative to other turfgrasses. The specific cultivars examined in this research were ‘Thermal Blue®’ and ‘Dura Blue®’. Experiments were conducted during 2003, 2004, and 2005 in Knoxville, TN. ‘Thermal Blue’ was seeded at 50, 100, 150, 200, and 250 kg·ha−1 of seed. ‘Thermal Blue's’ ideal seeding rate was between 100 and 150 kg·ha−1 of seed in 2003 and 50 kg·ha−1 in 2004. ‘Thermal Blue’ was also seeded in January, April, July, and September of each year with 100 kg·ha−1 of seed. All seeding dates took ≈11 months to become well established. However, July seeding produced poor turf quality (less than 6) and was the only seeding date deemed unacceptable. ‘Thermal Blue’ and ‘Dura Blue’ were fertilized with ammonium nitrate at 100, 200, and 300 kg N/ha/year and urea formaldehyde at 200 and 300 kg N/ha/year starting in March of each year. These treatments were maintained at 2-, 3.5-, and 5-cm mowing heights. ‘Thermal Blue’ had higher quality evaluations and produced more clippings than ‘Dura Blue’ throughout the year. Higher fertility regimens increased quality evaluations in April but decreased quality evaluations in October. Increasing the mowing height improved turf quality and decreased biomass production for both grasses. A proposed optimum method for establishment included seeding ‘Thermal Blue’ in April at 150 kg·ha−1 and fertilizing with 300 kg·ha−1 of nitrogen and them mowing at 5-cm height. ‘Thermal Blue’ and ‘Dura Blue’ are adapted for the transition zone, but summer heat stress may cause turf quality decrease in the fall.

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H. Brent Pemberton, Kevin Ong, Mark Windham, Jennifer Olson, and David H. Byrne

Rose rosette disease (RRD) is incited by a negative-sense RNA virus (genus Emaravirus), which is vectored by a wind-transported eriophyid mite (Phyllocoptes fructiphilus). Symptoms include witches broom/rosette-type growth, excessive prickles (thorns), discolored and distorted growth, and, unlike most other rose diseases, usually results in plant death. RRD is endemic to North America and was first described in Manitoba, Wyoming, and California in the 1940s. It has spread east with the aid of a naturalized rose species host and has become epidemic from the Great Plains to the East Coast of North America on garden roses in home and commercial landscapes where losses have been high. The disease was suggested to be incited by a virus from the beginning, but only recently has this been confirmed and the virus identified. The presence of the vector mite on roses has been associated with RRD since the first symptoms were described. However, more recently, the mite was demonstrated to be the vector of the disease and confirmed to transmit the virus itself. As a result of the RRD epidemic in North America and its effects on the national production and consumer markets for roses, a research team comprising five major universities (Texas, Florida, Tennessee, Oklahoma, and Delaware), a dozen growers and nurseries (all regions), six rose breeding programs (California, Wisconsin, Texas, and Pennsylvania), the major rose testing programs (Earth-Kind and AGRS), the major rose organization (American Rose Society), and the major trade organization AmericanHort has formed. This research project has been funded by the Specialty Crops Research Initiative through the U.S. Department of Agriculture (USDA) with the short-term objective of improving and disseminating best management practices (BMPs) and the long-term goal of identifying additional sources of resistance and developing the genetic tools to quickly transfer resistance into the elite commercial rose germplasm.

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Bobby H. Fletcher Jr., Michael F. Burnett, Krisanna L. Machtmes, and Jeff S. Kuehny

The primary purpose of this study was to determine the impact of participation in the Master Gardener program on horticultural knowledge and practice. In 1972, the “Master Gardener” concept was initiated in Washington State due to the high demand to answer consumer horticultural questions. The main objective of this program is to increase horticultural knowledge of program participants so they can transfer this information to consumer horticultural clientele. The program quickly spread throughout the United States. It reached Louisiana in 1994 and was expanded throughout most metropolitan areas by 1997. No formal evaluation has been conducted to determine the horticultural knowledge impacts of this program. All 257 participants in the 2004 Louisiana Master Gardener (LMG) program were surveyed before and after participation in this program. The survey used was a researcher-developed instrument designed to measure self-perceived knowledge, tested knowledge, and Best Management Practices (BMPs) used. Data were collected by master gardener coordinators and submitted to the researcher after each phase of data collection (pre and post). Results of the study revealed that the LMG participants were highly educated, mostly Caucasian, and mostly female. Significant improvements were identified in all of the knowledge and practice measurements included in the study. These included self-perceived knowledge, tested knowledge, and use of BMPs. It was concluded that the 2004 Louisiana Master Gardener program was effective in increasing the self-perceived horticultural knowledge and tested horticultural knowledge of program participants. In addition, the study concluded that the 2004 Louisiana Master Gardener program improved the use of BMPs among the participants.