Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: This project fielded a Best Management Practices (BMP) Implementation Team that has helped to guide the implementation activities for the Vegetable and Agronomic Crops BMP program. Activities included one-on-one evaluations of farms and grower practices which led to recommendations on BMPs to implement and enrollment in the Florida Department of Agriculture and Consumer Services (FDACS) BMP program. A series of educational activities across all spectrums of the agriculture industry has delivered information on the BMPs on new technologies to the growers. A coordinated program of educational events to make growers aware of these BMPs has been designed and is ongoing. Rapid adoption of the BMPs has been accomplished with a team funded by this project that is committed solely to BMP implementation and quality assurance. Over the course of the year, the BMP Implementation Team assisted in signing a total of 209 NOIs totaling 18,367 acres. This includes 153 citrus NOIs (14,441 acres), 29 Vegetable and Agronomic Crop NOIs (2,189 acres), 7 Container Nursery NOIs (53 acres), 2 Sod NOI (621 acres), and 18 Specialty Fruit and Nut Crops NOI (1,072 acres). Since the beginning of the BMP Implementation Team program, 2,136 NOIs have resulted from BMP Implementation Team activities, totaling 697,018 acres. We conducted 10 workshops related to impoving water and nutrient management for agricultural producers and held 12 field days to showcase BMPs in practice. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Florida agricultural producers in the container nursery, citrus, sod, cow/calf, vegetable, strawberry, blueberry, tropical fruit, and specialty fruit and nut industries. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The Shaw Farm in Suwannee County has 800 acres of irrigated farm fields. The ownerpurchased $2,500 of irrigation monitoring equipment at his own expense to make more informed irrigation decisions based on soil moisture levels. We worked to help him install the equipment, and assisted with data interpretation and decision making. Mr. Shaw quickly suggested that he had previously been overwatering his corn crop based on what he learned using the equipment. He estimated at that time, he had probably used 5" of irrigation water above the crop requirements. He applied the information he learned to all his irrigated acres. His experiences suggest that using this equipment season-long and knowledge gained would save about 173 million gallons of water on his farm this year compared to his previous practices. We are currently working with farmers on 15 different farm fields to implement this technology, where they can access their soil and irrigation data by computer or smartphone. Without the BMP Implementation Team delivering this technology and education, area farmers would have no exposure to alternative irrigation practices. We worked with a citrus nursery Polk County to monitor fertilizer and irrigation practices. Through the use of leaf tissue analysis and leachate sampling, we were able to convince the nursery manager that fertilizer application rates were excessive. The leaf nitrogen level (expressed on a dry weight basis) averaged 4.6%. There is no recommended standard for nursery trees (the recommended range for N in mature trees is 2.5-2.7%), but it is assumed to be somewhere around 3%. The nursery manager has completely discontinued weekly applications of soluble fertilizer. The manager estimated that he has reduced his annual fertilizer rate by 40%. He is now using the established nutritional ranges for bearing citrus as a guideline for determining annual fertilizer rate. The Murphy Farm in Hamilton County has 1,000 acres of irrigated farm fields. We have worked with Mr. Murphy since 2007 in implementation of BMPs on his farm. The Murphy Farm grows corn and peanuts on deep sandy soil and recognizes that irrigation management is critical to high yields and nutrient use efficiency. Upon our recommendation, Mr. Murphy purchased cell phone telemetry to retrofit irrigation monitoring systems he owns. We assisted him to install this equipment and helped him season long to interpret the information. With this equipment, Mr. Murphy was able to view soil moisture levels and rainfall at each farm field on his desktop computer. This helped him to make better irrigation management decisions and higher crop yields. He informed us that one farm where he used this equipment averaged 4,700 lbs per acre of peanuts. Because this farm had this equipment, he did not apply any irrigation in the final 60 days of the season, and reported an irrigation savings of about 4 inches per acre, or 21 million gallons of water. We are currently working with farmers on 15 different farm fields to implement this technology, where they can access their soil and irrigation data by computer or smartphone.
Publications
- Boman, B. J. 2012. Citrus best management practices. In: Advances in Citrus Nutrition. A. K. Srivastava (Ed.). Springer Science+Business Media B.V. 391-413.
- Boman, B. J., B. Boman, B. Sanden, T. Peters, and L. Parsons. 2012. Current Status of Microsprinkler Irrigation in the United States. Applied Engr. in Agric. 28(3): 359-366.
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Addition of organic amendments can alleviate the level of Al phytotoxicity in acid soils by affecting nature and quantity of Al species. This study evaluated the transformation of Al in an acidic sandy Alaquod soil amended with composts (10 and 50 g kg-1 soil of yard waste, yard+municipal waste, GreenEdge, and synthetic humic acid) based on soil Al fractionation by single and sequential extractions. Though the organic compost amendments increased total Al in soil, they alleviated Al potential toxicity in acidic soil by increasing soil pH and converting exchangeable Al to organically bound and other noncrystalline fractions, stressing the benefits of amending composts to improve acid soil fertility. Single extraction method appears to be more reliable for exchangeable Al than sequential extraction due to the use of non-buffered pH extract solution. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
There is a widespread of acidic soils in the USA, including Florida. Aluminum (Al) toxicity is one of the major constraints for crop production on these soils. Each year, large amounts of liming materials are applied to neutralize soil acidity and to reduce Al toxicity to sustain desired yield, which is costly, and sometimes does not lead to expected results due to over correction of soil pH. The results from this study indicate that amendment of organic composts can be an important and effective management practice for alleviating Al toxicity in acid soils. There are plenty of organic matter sources in this country such as municipal composts, farm manures, and biosolids. Disposal of them by incineration could be expensive, but they can be beneficially used to remediate acidic soils. In this regards, the results from this study merit consideration in the development of best management practices for agriculture in the acidic soil regions.
Publications
- Lu, Q., Z. L. He, D. A. Graetz, P. J. Stoffella , and X. E. Yang. 2009. Phytoremediation to remove nutrients and improve eutrophic stormwaters using water lettuce (Pistia stratiotes L.). Environ. Sc. Pollution Res. (accepted).
- Vieira F.C.B., Z. L. He, C.P. Wilson, and C. Bayer. 2009. Speciation of Al in solution of an acidic sandy soil amended with organic composts. Commun Soil Sci. Plant Anal. (in press) Yang,Y.G., Z.L. He, P.J. Stoffella, X.E. Yang, D.A. Graetz4, and D. Morris. 2008. Leaching behavior of phosphorus in sandy soils amended with organic material. Soil Sci. 173 (4): 257-266.
- Vieira, F. C. B., Z. L. He, C. Bayer, P. J. Stoffella, and V.C. Baligar. 2008. Response of representative cover crops to aluminum toxicity, phosphorus deprivation, and organic amendment. Aust. J. Agric. Res. 59 (1):52-61.
- Yang,Y.G., Z.L. He, P. J. Stoffella, D. A. Graetz, X.E. Yang, and D. J. Banks. 2008. Leaching Behavior of Lead, Zinc, Cadmium, Cobalt, Copper, Chromium and Nickel from Biosolids-amended Sandy Soils. Compost Sci. & Util. 16: 144-151.
- Vieira, F. C. B. Z. L. He, C. Bayer, P. J. Stoffella, and V.C. Baligar. 2008 (Oct). Organic amendment effects on the transformation and fractionation of Al in acidic sandy soil. Commun Soil Sci. Plant Anal. 39 (17 & 18): 2678-2694.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Results of the aquaculture research were disseminated at scientific conferences, extension meetings, in-service trainings for extension agents, directly to current producers, and via radio broadcasts. PARTICIPANTS: Matthew A. DiMaggio - Graduate Student University of Florida Scott W. Grabe - Research Biologist University of Florida TARGET AUDIENCES: Target audiences include current and potential aquaculture producers and research and extension personnel. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
A Florida endemic freshwater killifish, Fundulus seminolis, commonly called a Seminole Killifish or a Mud or Bull Minnow was evaluated for its aquaculture potential as a freshwater and marine bait fish. Adult F. seminolis were collected from the wild and held in quarantine. A survey of the parasites present on the skin, fin, gill, and intestine was conducted. The most common parasite found are members of the subclass Digenea and they were found in some sampled fish in all four tissues sampled. A 95% occurrence of Digenea was found in the intestines. F. seminolis were exposed to acute salinity changes by taking fish acclimated to freshwater and immediately exposing them to 8, 16, 24, and 32 ppt salinity using both a commercially available NaCl salt product and natural sea water. Survival was assessed over 72 hours. Results indicate that fish exposed to NaCl salt survived acute salinity change up to 16 ppt while fish exposed to natural sea water were capable of survival in 24 ppt salinity. No fish were able to survive an acute salinity change to 32 ppt. These results are critical to several commercial producers of F. seminolis and their desire to market these fish as marine baitfish. The producers now have defined methods for acute salinity acclimation and have a better knowledge of F. seminolis salinity tolerances.
Publications
- Ohs, C.L. and L.R. D'Abramo. 2006. Comparison of early season versus late season trap schedules for harvest of Red Swamp Crawfish Procambarus clarkii cultured in earthen ponds without planted forage. Journal of Shellfish Research 25(2): 561-564. Ohs, C.L., L.R. D'Abramo, and A.M. Kelly. 2006. Evaluation of dietary administration of 17 alpha - methyltestosterone to freshwater prawn Macrobrachium rosenbergii as a means to control sexual differentiation. Journal of the World Aquaculture Society 37(3): 328-333.
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Progress 10/01/05 to 09/30/06
Outputs
Research evaluated different methods to increase the value of cultured shrimp in Florida. The feasibility of modifying the flavor of shrimp through post-harvest saltwater acclimation and methods to prevent melanosis of the harvested shrimp were evaluated. Survival was determined at different acclimation rates. The highest survival was achieved when salinity was increased at 1 ppt/hr using NaCl. Salinity changes in excess of 2 ppt/hr were lethal when increasing salinity from 4 to 28 ppt. Further research is needed to identify if 2 ppt/hr can be used to raise salinity to 20 ppt then the fianl 8 ppt increased at 1 ppt/hr or less. Flavor of shrimp acclimated to 24 ppt salinity was preferred over shrimp raised at low salinity when provided to a taste panel. The level and rate of melanosis formation was compared between various preservatives applied to harvested shrimp at different concentrations. Melanosis was significantly reduced following treatment with everfresh in
comparison to the use of sulfites. The feasibility of water-less live shipment of shrimp, as a method to enter Florida produced shrimp into the high dollar live markets in the northern U.S. and Canada was evaluated. Survivability following various packing protocols was determined. Results suggest marine shrimp cultured in low saline ponds do not tolerate packaging and shipping in moist or low water volume packing material as reported for other full saline cultured shrimp and freshwater prawns. Salinity needs to be raised to approximately 10 ppt before acceptable survival rates post-shipping can be obtained. Survival is increased by adding approximately 2 cm of water in the bottom of the shipping container over the use of moist packing material only. Temperatures need to be lowered to increase survival and the optimal temperature range for packaging and shipping is 14-16C. Moistened packing materials such as pine sawdust, newspapers, and cheese cloth were evaluated. Pine saw dust
caused low pH conditions which was lethal. Previous successful reports of water-less shipping used sawdust originating from Teak. Teak sawdust was unavailable for comparison. Marine baitfish broodstock including Atlantic spot (Leiostomus xanthurus), Atlantic croaker (Micropogonias undulates), pigfish (Orthopristis chrysoptera), and bull minnows (Fundulus grandis) were collected and conditioning for spawning was initiated.
Impacts
The results of the shrimp salinity acclimation rates may be used by producers to modify or improve the flavor of shrimp cultured in low saline conditions and allow for marketing in higher priced niche markets. The data generated on live shipment of shrimp in minimal or no water may prove useful for producers in Florida desiring to market their shrimp in distant high dollar live markets. Marine baitfish research results will help define appropriate culture methods and systems necessary for commercial grow-out of baitfish. In addition, the data generated will provide an estimate on the time required for various marine baitfish to reach market size and the number of crops that can be produced per year.
Publications
- Ohs, C.L. and L.R. D'Abramo. 2006. Comparison of early season versus late season trap schedules for harvest of Red Swamp Crawfish Procambarus clarkii cultured in earthen ponds without planted forage. Journal of Shellfish Research 25(2): 561-564.
- Ohs, C.L., L.R. D'Abramo, and A.M. Kelly. 2006. Evaluation of dietary administration of 17 - methyltestosterone to freshwater prawn Macrobrachium rosenbergii as a means to control sexual differentiation. Journal of the World Aquaculture Society 37(3): 328-333.
- Ohs, C.L., L.R. D'Abramo, L. Petrie-Hanson, and A.M. Kelly. 2006. Apparent control of sexual differentiation of freshwater prawn Macrobrachium rosenbergii through dietary administration of dopamine hydrochloride. Journal of Applied Aquaculture 18(3): 19-32.
- D'Abramo, L.R., C.L. Ohs, and K.C.E. Elgarico. 2006. Effect of added substrate on production of red swamp crawfish (Procambarus clarkii) in earthen ponds without planted forage. Journal of the World Aquaculture Society 37(3): 307-312.
- D'Abramo, L.R., C.L. Ohs. 2005. Management practices for production of the red swamp crayfish Procambarus clarkii in earthen ponds without planted forage. Aquaculture in the 21st Century. Eds. A.M. Kelly and J. Silverstein. American Fisheries Society Symposium 46: 171-178. American Fisheries Society, Bethesda, MD.
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Progress 10/01/03 to 09/30/04
Outputs
Preliminary trials and investigations have been conducted in pre-harvest cultural practices and postharvest handling techniques of fresh fruits and vegetables. Postharvest decay of fresh fruits and vegetables can occur from both pre- and postharvest infection and effective control methods must be implemented throughout the pre- and postharvest life of these commodities. With the loss of benomyl, a widely used preharvest fungicide with residual postharvest decay control, there has been an urgent need to evaluate potential replacements. Various trials were conducted demonstrating that, out of 11 different preharvest-applied compounds (mostly fungicides), Topsin (thiophanate-methyl) was the only one that consistently reduced postharvest stem-end rot of citrus similar to benomyl. Furthermore, after evaluating postharvest quality of four different citrus fruit varieties grown on 14 different rootstocks, it is clear that the choice of citrus rootstock can reduce the
occurrence of postharvest stem-end rind breakdown (a physiological peel disorder) by more than half, and influence postharvest decay by more than 40%. Postharvest hot water treatments have been studied and used as non-chemical methods to reduce postharvest decay and chilling injury (CI) in fresh citrus fruit. While many studies have been performed in Mediterranean climates, there exists relatively little work evaluating the effects of hot water (HW) on Florida grapefruit quality and quality retention during postharvest handling. Current studies confirmed the reduction of CI development in grapefruit after HW treatments, but found that the treatments had a greater affect on inner-canopy fruit (32% reduction in CI) compared to more CI-sensitive outer-canopy fruit (10% reduction in CI). In addition, washing and coating the fruit with shellac immediately after the HW treatment significantly reduced hot water injury.
Impacts
As a result of our work and strong industry support, a Sec. 18 emergency registration for preharvest application of Topsin on citrus to control postharvest stem-end rot was issued in February 2004 and is being renewed for the 2005-06 season. It is expected that knowledge about rootstock affects on postharvest quality and storage life will aid citrus growers in choosing the best rootstock for the fresh fruit operation. Work on postharvest hot water citrus treatments will build upon the current findings until suitable commercial recommendations can be made.As a result of our work and strong industry support, a Sec. 18 emergency registration for preharvest application of Topsin on citrus to control postharvest stem-end rot was issued in February 2004 and is being renewed for the 2005-06 season. It is expected that knowledge about rootstock affects on postharvest quality and storage life will aid citrus growers in choosing the best rootstock for the fresh fruit operation.
Work on postharvest hot water citrus treatments will build upon the current findings until suitable commercial recommendations can be made.
Publications
- Ritenour, M.A., Dou, H., Bowman, K.D., Boman, B.J., Stover, E. and Castle, W.S. 2004. Effect of rootstock on stem-end rind breakdown and decay of fresh citrus. HortTechnology 14(3):315-319.
- Ezz, T. M., Ritenour, M.A. and Brecht, J.K. 2004. Hot water and elevated CO2 effects on proline and other compositional changes in relation to postharvest chilling injury of Marsh grapefruit. J. Amer. Soc. Hort. Sci. 129(4):576-582.
- Stover, E., Pelosi, R., Burton, M., Ciliento, S. and Ritenour, M. 2004. Performance of Oroblanco and Melogold on nine rootstocks in Florida's Indian River region. HortScience 39(1):28-32.
- Ritenour, M.A., Pelosi, R.R., Burton, M.S., Stover, E.W., Dou, H. and McCollum, T.G. 2004. Assessing the efficacy of preharvest fungicide applications to control postharvest diseases in Florida citrus. HortTechnology 14 (1):58-62.
- Karrupiah, K.J.J., Ritenour, M.A., Burton, M.S., Brecht, J.K. and McCollum, T.G. 2004. Short-duration, hot water treatment for the control of chilling injury and postharvest decay in citrus. Proc. Fla. State. Hort. Soc. 117: (in press)
- Ritenour, M.A., Albrigo, L.G., Burns, J.K. and Miller, W.M. 2004. Granulation in Florida Citrus. Proc. Fla. State. Hort. Soc. 117: (in press)
- Ritenour, M.A., Timmer, L.W., Roberts, P.D. and Chung, K.R. 2004. 2005 Florida Citrus Pest Management Guide: Preharvest Control of Postharvest Decays. IFAS Fact Sheet PP48.
- Dou, H, Ritenour, M.A. Zhang, J. and Timmer, L.W. 2004 Impacts of the 2004 Florida hurricanes on postharvest handling of fresh citrus. Packinghouse Newsletter (IFAS) 201:1-4.
- Brecht, J.K., Ritenour, M.A. and Sargent, S.A. 2004. Advances in Temperature Monitoring Management. American Vegetable Grower, August, p. 36.
- Sargent, S.A., Ritenour, M.A. and Brecht, J.K. 2004. The Use of Ethylene Gas. American Vegetable Grower, May, p. 41.
- Ritenour, M.A., Sargent, S.A. and Brecht, J.K. 2004. Reducing Water Loss From Fresh Vegetables. American Vegetable Grower, Feb., p. 54.
- Huber, D., Jeong, J. and Ritenour, M. 2004. The Power of 1: Use of 1-methylcyclopropene (1-MCP) may enhance shelf life and quality retention for tomatoes and avocadoes. Florida Grower, April, p. 14
- Ritenour, M.A., Stoffella, P.J. He, Z. and Burton, M.S. 2004. Postharvest calcium chloride dips of whole tomato fruit reduce postharvest decay. HortScience 39:806-807.
- Simonne, A., Brecht, J.K. Ritenour, M.A. Sargent, S.A. and. Schneider, K.R. 2004. Features of the UF worker health and hygiene training program for fresh produce in Florida. FSHS 2004 Program and Abstracts; available at http://www.fshs.org/.
- Ritenour, M.A., Albrigo, G. and Burns, J. 2004. Granulation of Florida citrus. FSHS 2004 Program and Abstracts; available at http://www.fshs.org/.
- Syvertsen, J.P., Albrigo, L.G. Ritenour, M.A. Vachon, R.C. Dunlop, J.M. Pelosi, R.R. and. Burton, M.S. 2004. Growth conditions affect sheepnosing in grapefruit. FSHS 2004 Program and Abstracts; available at http://www.fshs.org/.
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Progress 10/01/02 to 10/01/03
Outputs
Hymenachne amplexicaulis is an exotic semi-aquatic grass from South America that is invading freshwater wetland systems in central Florida. In 2000, Ischnodemus variegatus, an exotic insect from South America, was found feeding on H. amplexicaulis in Myakka River State Park. This insect had not previously been known to occur in Florida. The influence of Ischnodemus variegatus feeding on photosynthesis and growth of Hymenachne amplexicaulis, was investigated in field and greenhouse environments. In the field, carbon dioxide assimilation of infested plants was approximately 35% less than non-infested plants, and the rate of assimilation was related to I. variegatus density. The relative growth rate of infested plants in the greenhouse was 77% of non-infested plants, and biomass of infested plants was significantly less than non-infested plants 79 days after infestation. However, plants were not killed, even though densities were relatively higher than those commonly
observed in the field. Determining the value of I. variegatus as a biological control agent of H. amplexicaulis requires additional research. In the field, plants are stressed by a variety of factors, including climate, water and soil nutrient levels, pathogens, herbivores and competition with other plants. Hymenachne amplexicaulis has low drought tolerance and thus a combined effect of low water availability and insect damage may have additive negative effects on H. amplexicaulis growth. Additionally, I. variegatus may influence flowering and seed production, which were not measured in our experiments. A negative impact on seed production could conceivably slow the spread of H. amplexicaulis in Florida's wetlands. Finally, an overall assessment of the value of I. variegatus to natural resource management and agriculture in Florida will depend on its host range. Studies are currently being conducted to determine whether I. variegatus will feed and survive on native and economically
important plants in Florida.
Impacts
Information gained from this study will be useful in determining the ecological impact of the introduction of I. variegatus into Florida, which in turn will help to define a management approach for H. amplexicaulis. Additionally, host range studies will determine whether I. variegatus will be beneficial or detrimental to Florida's natural resources.
Publications
- Overholt, W. A., S. M. L. Ewe, R. Diaz, E. C. Morgan and O. E. Moeri. 2004. Feeding effects of Ischnodemus variegatus (Hemiptera: Blissidae) on photosynthesis and growth of Hymenachne amplexicaulis (Poaceae). Florida Entomologist (submitted).
- Diaz, R., W. A. Overholt and J. P. Cuda. 2004. Exotics in the Wetlands: West Indian Marsh Grass. EDIS publication. ENY-693 (in review).
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Progress 10/01/01 to 10/01/02
Outputs
Yield, tree size and fruit quality have been assessed for the 6th through 9th year of a replicated trial of 'Oroblanco' and 'Melogold' on 9 rootstocks in the Indian River citrus region of Florida. Through 9 years of age, yield has been extremely low for 'Melogold', with trees on Swingle cropping best but producing an average of only 13 kg per tree in 2001. 'Oroblanco' has cropped well producing an average of 100 kg per tree in 2001. The highest yields were observed for 'Oroblanco' on X-639 rootstock, with 192 kg / tree, which was 50% higher than the next best rootstocks which were Swingle and Smooth Flat Seville. Preliminary studies were initiated to evaluate exotic insects in Central America that could prove useful in controlling Florida invasive insects and weeds. Over eight hundred current and potential students of the Indian River Research and Education Center (IRREC) were surveyed to assess preferences for academic content and structure. Results will help IRREC
faculty and staff tailor the teaching program to meet the needs of students.
Impacts
The finding of improved production with Oroblanco variety will be economically beneficial to the Florida Citrus industry. Studies to develop new biocontrol strategies using exotic insect species will be beneficial in reducing the impact of invasive insect and plant pests on Florida's ecology. The study of student needs will improve educational programs offered at the Indian River Research and Education Center.
Publications
- Minton, T.M. and Willett, L.S. 2002 An analysis of the Indian River Research and Education Center student needs survey." Economic Information Report EI 02-2. Food and Resource Economics Department. University of Florida. Minton, T.M. and Willett, L.S. "Preferences of Agricultural Students for Academic Content and Structure at a Branch Campus Location." NACTA Journal.
- Minton, T.M. and Willett, L.S. 2002. Student preferences for academic structure and content in a distance education setting. The Online Journal of Distance Learning Administr.
- Stover, E., Castle, W. 2002. Citrus rootstock usage in the Florida Indian River region. HortTechnology 12:143-147.
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Progress 10/01/00 to 10/01/01
Outputs
The presence of pesticides in tributary water from citrus production areas is a concern within the St. Lucie Estuary Drainage Basin. However, little data are available indicating the scale of the perceived problem, or the presence of a comprehensive array of pesticides that may be ecologically significant. The objective of this project is to characterize trends in selected pesticide levels in canal water leaving the North St. Lucie Water Control District throughout a three-year period. This water control district is an ideal location for such an analysis because all of the water contained within it leaves through identifiable, discrete points (i.e. Gordy Road structure on Ten-Mile Creek, and Pump Stations). The dominant land-use within the basin is citrus. Water samples were collected daily at the Gordy Road structure when water was discharged downstream. In addition, grab samples were collected every-other day during periods when water was not being discharged.
Samples were analyzed for the following: (N-methyl carbamates and N-methyl carbamoyloximes) aldicarb, aldicarb sulfone, aldicarb sulfoxide, propoxur, carbaryl, carbofuran, methiocarb, methomyl, oxamyl; and (organophosphates) azinphos-methyl, chlorpyrifos, diazinon, dimethoate, ethion, fenamiphos, malathion, methidathion. Most of these pesticides are labeled for use in citrus production, and pose significant acute risks to aquatic organisms if they are present in water at sufficient levels. For the N-methylcarbamate and N-methylvarbamoyloxime analysis, a total of 169 samples were collected an analyzed. Aldicarb and two of its' degradates (aldicarb sulfone and aldicarb sulfoxide) were detected in 8.9, 16.6, and 7.7% of the samples taken, respectively. Carbaryl was also detected in 7.7% of the samples analyzed. Oxamyl and methomyl were detected in very few samples (0 and 0.6%, respectively). The detections of aldicarb and its' degradates appear to be associated with the early spring
runoff, which is expected due to their high water solubilities. The oxidation product aldicarb sulfone continued to be detected in discharge water through the end of July, after which very little was detected. Ethion was the only organo-phosphate pesticide detected. It was quantifiably detected in 19 samples during the 197 day monitoring period. All of the detections occurred on consecutive days, beginning on August 1st. Ethion is usually only applied during the summer months. According to the water discharge data, a significant runoff event associated with several inches of rain also occurred during the first and second weeks of August. Based on Florida acute and chronic toxicity criteria, an acute risk to Ethion may exist depending on the zooplankton species. Chronic risks are also likely to exist based on these criteria. No other organophosphates were detected during the 197 day monitoring period, indicating that they posed little risk during the monitoring period. Few conclusions
can be made with confidence at this point since the project if fairly new. Monitoring will continue for two more years, pending funding.
Impacts
Data from this study will be useful in establishment of a baseline for the occurrence of these pesticides in water leaving a predominantly citrus production area. This in turn will help measure the effectiveness of future pesticide BMP implementation in the watershed.
Publications
- (Abstract) Wilson, P.C. 2001. Characterization of the occurrence of selected N-methyl carbamate, N-methyl carbamoyloxime, and organo-phosphate pesticides in canal water leaving the North St. Lucie Water Control District. 22nd Annual meeting of the Society of Environmental Toxicology and Chemistry (SETAC), Baltimore, MD, 10-15 November.
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Progress 10/01/99 to 09/30/00
Outputs
The major objective was to develop, evaluate, and recommend new organic media alternatives for peat used in container-grown ornamental crop production systems. The specific objectives were to (1) Evaluate physical and chemical characteristics and nutrient composition of mixtures of coir, compost, and peat as viable potting media alternatives as compared with traditional, commercially available peat-based potting media, and (2) Evaluate plant growth, development, nutritional composition, and consumer quality of several ornamental crops as influenced by alternatives to peat-based potting media. Ten different perennial plant species and eleven different combinations of media amended with compost were evaluated. Generally, we found that up to 50% compost can be incorporated into commercial media without affected plant growth and development. Plants grown in 100% compost were somewhat smaller but generally considered marketable. However, the effect of compost on plant
growth was species specific. As compost composition in peat-based media increased from 0% to 100%, carbon/nitrogen (C/N) ratios decreased; and media stability, N mobilization, pH, and electrical conductivity (EC) increased. Bulk density, particle density, air-filled porosity, container capacity, and total porosity increased as more compost was added to peat-based media. The physical properties of compost reduced root development. Therefore, additional studies were designed to develop a compost-based media better suited for perennial plant production. While aerating the compost-based media improved plant growth, root distribution was still abnormal. Current studies are underway to investigate the prospect of sub-irrigating plants grown in compost-based media as opposed to hand watering or drip irrigating.
Impacts
Peat is used extensively in the nursery industry as a primary component in commercial soilless potting media. The increased use of peat as an organic amendment with superior water holding capacity is challenged by economic and environmental pressures. To stay competitive and satisfy environmental concerns, potential alternatives to peat need to be investigated. Commercially available peat- and coir-based soilless mixes were amended with 25%, 50%, 75% or 100% organic compost generated from biosolids and yard trimmings. Results suggest that compost can be a viable partial alternative to peat or coir as a substrate for containerized herbaceous perennial production. Media amended with 50% compost (v:v) provided plants of similar appearance to unamended media. A higher compost amendment (75 or 100%) reduced plant growth. Partially amending peat- or coir-based media with compost may have positive economic consequences for commercial perennial production due to the rising
costs of peat.
Publications
- Wilson, S.B., P.J. Stoffella, and D.A. Graetz. 2000. Organic media alternatives to peat for container-grown golden shrimp plant production. HortTechnology. In press.
- Wilson, S.B., P.J. Stoffella, and D.A. Graetz. 2000. Use of compost as a media amendment for containerized production of two tropical perennials. J. Environ. Hort. In press.
- Wilson, S.B., P.J. Stoffella, and D.A. Graetz. 2000. Compost-amended media for growth and development of mexican heather. Compost Science & Utilization. In press.
- Krumfolz, L.A., S.B. Wilson, and P.J. Stoffella. 2000. Use of compost as a media amendment for containerized production of the perennial, Cat Whiskers. Proc. Southern Nursery Assoc. In press.
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Progress 10/01/98 to 09/30/99
Outputs
Technical barriers are a type of non-tariff restriction on international trade that has emerged at the center of agricultural policy disputes with increasing frequency, particularly since completion of the Uruguay Round GATT negotiations in 1993. Questionable technical barriers applied to U.S. agricultural exports, including citrus, vegetable, and ornamental crops, were widespread as the Agreements came into effect, and may have limited U.S. export revenue by nearly $5 billion in 1996. Political economy determinants of such barriers were evaluated empirically using PROBIT, Poisson, and TOBIT regression techniques. A robust result is a negative relationship between the relative contribution of agriculture to an economy and the application of questionable technical barriers to U.S. agricultural exports. There is also evidence of substitution between questionable technical barriers and other forms of border protection, and of the reduced use of these barriers with
increased openness of an economy or trade opportunities faced by its own agriculture. When complemented with evidence accumulating in the WTO from notifications, informal complaints, and formal dispute settlements, the difficulty in separating economic and political factors from policy outcomes becomes even more apparent.
Impacts
(N/A)
Publications
- Suzanne Thornsbury. "Political Economy Determinants of Technical Barriers to U.S. Agricultural Exports," International Working Paper Series IW99-3. International Agricultural Trade and Development Center. University of Florida, August 1999.
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Progress 10/01/97 to 09/30/98
Outputs
Field evaluation of nutrient release from composts is important to estimate the nutrient contribution to crops, potential leaching of nutrients, and ultimately to determine optimum application rates, timing, and placement of composts. Field incubation and laboratory analyses were conducted to evaluate the mineralization rate and transformation of N in biosolids (BSD), yard waste (YW), and biosolids plus yard waste (BSD + YW) composts. Each compost was packed into PVC columns (8 cm h and 5 cm id) and inserted vertically into the upper layer of an Oldsmar fine sand (sandy, siliceous, hyperthermic Alfic Haplaquods) of raised citrus beds. The top end of the PVC column was capped to prevent excessive leaching of nutrients from the columns. At monthly intervals, a set of the incubated columns was removed and the soil underlying each column (a core of 20 cm height and 6 cm diam) was sampled to analyze KCI extractable NH4 -N and NO3 -N. Total C and N of the incubated composts
were determined at the end of the 1-yr incubation. The N mineralized during one year's incubation was 13.3, 16.5, and 32.8% of the total N in the YW, BSD +YW, and BSD, respectively. The N mineralization reaction of each compost was best described by a Langmuir-type kinetic or a two-constant kinetic model. The mineral N (NH4 -N and NO3 -N) recovered from both the compost and the underlying soil, by KCI extraction, accounted for at best 52, 86 and 89% of the total mineralized N for the BSD + YW, YW and BSD, respectively. During the first 6 months of incubation, NH4 was the dominant form of mineralization N, but NO3 accounted for more than 50% of the mineral N during the later part of the incubation. Application rates, timing, and placement of composts with high N concentration and low C/N ratio (BSD) should be taken into consideration since its N release is quite high.
Impacts
(N/A)
Publications
- No publications reported this period
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Progress 10/01/96 to 09/30/97
Outputs
This project was initiated to determine the potential for enhancing economic value of fresh-market citrus using plant growth regulators in Florida. Economic assessment of previously collected data indicated that increased fruit size in chemically thinned tangerines enhanced returns by $1000-1500/ha. Analyses of grapefruit size vs. cropload indicated substantial but lower benefits may be attained through chemical thinning. NAA, alone and combined with several adjuvants, was applied at 100-400 mg/liter to heavily cropping Marsh grapefruit and Sunburst tangerine in the Indian River area in mid-May 1997. Application occurred during June-drop when mean fruitlet diameter was 18 mm for Sunburst and 46 mm for Marsh. One inch of rain fell within four hours of Sunburst treatment. No significant abscission occurred in Marsh following application. Considerable drop occurred in the month following Sunburst treatment, but there was no effect of treatment. Effects of AVG dips on
fruit quality were assessed using May-harvested Marsh. Fruit stored 3 weeks at RT following harvest had significantly higher brix and juice extraction efficiency when dipped in 400 mg/1 AVG before storage. Preliminary tests of GA application to Fallglo indicate modest reduction in postharvest pitting. Tests of GA spray-burn in Marsh indicate that addition of Silwet significantly enhances fruit marking. Initial assessments suggest that use of 10 mg/1 GA with Silwet greatly reduces marking compared to 20 mg/1.
Impacts
(N/A)
Publications
- No publications reported this period
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Progress 10/01/95 to 09/30/96
Outputs
With the cooperation of the Agricultural Extension Service, numerical and alphabetical books were published of the tropical forage legumes that have been evaluated at the Research Center. Books will be distributed to appropriate Florida, National, and International cooperators who have donated their passport books to our Center. Approximately 7000 passport records include 96 legume genera. Records include country, city, latitude, longitude, and altitude of collection sites, and corresponding other countries ID. Seeds are stored in a -15 degrees C germplasm bank and representative dried herbarium specimens are maintained for reference.
Impacts
(N/A)
Publications
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Progress 10/01/94 to 09/30/95
Outputs
The objectives of this study were to investigate the distribution of Fe, Mn, Cu,Zn and P in soil profiles with various forms, and to determine the relations of distribution and soil acidity, texture and organic matter in Florida Spodosols, Alfisols and Entisols under citrus production. Samples were taken from 11 soil pedons representing 11 soils series in Florida citrus area. The fractionation of the elements among organic and inorganic forms was accomplished by a sequential extraction procedure. Total secondary Fe content fluctuated with depth, closely related to the clay content, and mainly was present in amorphous and crystalline forms. Total secondary Mn, Cu and Zn contents were highest in the Ap horizons and decreased sharply with depth. These three elements mainly were present in organically bound forms in Spodosols, and in organically bound, associated with Mn oxide and amorphous Fe oxide forms in Alfisols and Entisols. Exchangeable Ca and soil pH were
relatively hi gh in the Ap horizons due to the liming practices in citrus production, which may improve the availability of P and prevent Cu and Mn toxicity.
Impacts
(N/A)
Publications
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Progress 10/01/93 to 09/30/94
Outputs
Spodosols are the important soil types through much of the citrus belt in the south and east coast of Florida. It is strongly believed that the spodic horizon restricts the transport of contaminants, hence minimizes the contamination of groundwater by agrichemicals. In this study, adsorption and leaching of nitrate, bromide, and phosphate in soils taken from three horizons in a Florida spodosol were evaluated with batch equilibration and leaching column experiments. Adsorption of nitrate and bromide was negligible in A1 (surface soil, 0-20 cm) and A2 (sand layer, 25-50 cm). The spodic horizon (55- 70 cm) in a disturbed condition did not retain appreciable amounts of nitrate (or bromide), nor did it decrease the transport of either ions in a leaching column study. A significant fraction of applied P was adsorbed by the surface and spodic horizons, which confirms with the minimal P being leached when either of the two horizon samples was used in the leaching column
study.
Impacts
(N/A)
Publications
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Progress 10/01/91 to 09/30/92
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 10/01/90 to 09/30/91
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 10/01/89 to 09/30/90
Outputs
Preliminary research trials and explortory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 10/01/88 to 09/30/89
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 10/01/87 to 09/30/88
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 10/01/86 to 09/30/87
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 10/01/85 to 10/30/86
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 10/01/84 to 10/30/85
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 10/01/83 to 09/30/84
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 01/01/83 to 12/30/83
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 01/01/82 to 12/30/82
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 01/01/80 to 12/30/80
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 01/01/79 to 12/30/79
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 01/01/78 to 12/30/78
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 01/01/77 to 12/30/77
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 01/01/76 to 12/30/76
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements when they are completed.
Impacts
(N/A)
Publications
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Progress 01/01/75 to 12/30/75
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements as soon as these are completed.
Impacts
(N/A)
Publications
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Progress 01/01/74 to 12/30/74
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements as soon as these are completed.
Impacts
(N/A)
Publications
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Progress 01/01/72 to 12/30/72
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements as soon as these are completed.
Impacts
(N/A)
Publications
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Progress 01/01/71 to 12/30/71
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements as soon as these are completed.
Impacts
(N/A)
Publications
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Progress 01/01/69 to 12/30/69
Outputs
Preliminary research trials and exploratory investigations are being conducted and data will be submitted under project statements as soon as these are completed.
Impacts
(N/A)
Publications
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