HortScience: a publication of the American Society for Horticultural Science
... for the 2004 growing season, less than 4% of those hectares were managed according to nationa... more ... for the 2004 growing season, less than 4% of those hectares were managed according to national organic standards (K. Hardison, personal communication ... systems indicate the benefits of surface mulch are best realized when the duration of the crop season is long (Hoyt, 1999 ...
The tropical legume sunn hemp (Crotalaria juncea L.) is primarily used a summer cover crop in sou... more The tropical legume sunn hemp (Crotalaria juncea L.) is primarily used a summer cover crop in southeastern vegetable crop production systems. Farmers value sunn hemp for its many benefits to the farming system including rapid growth, high biomass yield, efficient nitrogen (N) fixation, and weed and nematode suppression. Seed is imported from production areas in southern Africa at a cost of $7.00-9.00 kg-1. Cultivars available for purchase are predominantly short-day varieties and consequentially fail to produce adequate seed in the normal period of summer cover crop production (six to eight weeks in Florida). The effects of cultural practices used to manipulate floral initiation and seed production have not been fully examined on biomass production, N sequestration and N mineralization. A 2-year field trial was conducted in the Organic Unit at the UF-IFAS Plant Science Research and Education Unit in Citra, FL to ascertain if managing sunn hemp for seed production would provide addit...
Recirculating greenhouse irrigation is becoming a more common practice for vegetable growers in t... more Recirculating greenhouse irrigation is becoming a more common practice for vegetable growers in the US due to growing concern over freshwater shortages. Utilizing closed loop irrigation systems for greenhouse vegetable production not only saves the grower money due to reduced water and fertilizer use, it also reduces the amount of fertilizers being dispensed into the environment as spent irrigation. One drawback is that water-borne pathogens such as Pythium, Phytopthora, and Fusariam may proliferate in these irrigation systems. To prevent further spread of these pathogens irrigation is disinfected using chemical sanitizers such as chlorine, chlorine dioxide, ozone, and hydrogen peroxide. Chlorine dioxide is advantageous over other widely-used chemical sanitizers because it is active over a wide pH range, it has a high oxidation capacity, and compared to chlorine it doesn’t form carcinogenic halogenated compounds and is effective on organisms resistant to chlorine. Currently there is...
The growth in organic market opportunities has increased the demand across the country for inform... more The growth in organic market opportunities has increased the demand across the country for information on all aspects of organic agricultural production. Until recently, there has been little published Extension information on organic agricultural practices as science-based information was scarce. In addition, science-, experience-, and regulation-based organic agriculture information must be aggregated and integrated to produce information of the greatest utility to farmers and agricultural professionals. eOrganic works to fill this need and become an important national source of organic agriculture information by: 1) convening a national community of researchers, extension and other agricultural professionals, farmers, and certifiers at eOrganic.info; 2) facilitating project management, networking, and co-learning; 3) supporting collaborative development and publication of peer-reviewed articles, FAQs, and videos at eXtension.org/organic_production; and 4) facilitating engagement ...
Recycling greenhouse irrigation water is becoming a popular practice due to water conservation ef... more Recycling greenhouse irrigation water is becoming a popular practice due to water conservation efforts worldwide. However, water must be sanitized prior to recirculation to prevent contamination with plant pathogens. Chlorine dioxide (ClO2), a common disinfectant used to treat municipal water and postharvest dump tanks, has been proposed as a disinfectant for recirculated irrigation systems. Little research has been performed to determine if this chemical is appropriate to use for irrigation on greenhouse specialty crops. The objective of this study was to determine the effects of ClO2 on the vigor of bell pepper plants grown in two different soilless medias (perlite and pine bark). Plants were transplanted in the University of Florida Protected Agriculture Project Greenhouse in Nov. Chlorine dioxide was added to the irrigation solution 11 days after transplanting at concentrations of 0, 10, 20 and 40 ppm. Relatively high concentrations were used to estimate an upper threshold for p...
Mulching by spreading organic matter around plants has been shown to increase plant tolerance to ... more Mulching by spreading organic matter around plants has been shown to increase plant tolerance to insect pests. Also, mulches help in maintaining soil moisture required for plant vigor and thus improve soil water and nutrient status for plant growth. A field experiment was conducted to determine the impact of different kinds of mulches (pine bark, sunn hemp (Crotalaria juncea), sorghum-sudangrass (Sorghum bicolor x S. sudanense), cowpea (Vigna unguiculata), or non-mulched control) on the soil surface insect community. The five treatments were replicated five times in a randomized block design. Insects were evaluated every two weeks using two pitfall traps per plot. Soil surface insects were also sampled using other methods such as wooden board traps. The total number, order, and family of all arthropods found in the traps were recorded. Weeds, nematodes, and plant stand were also evaluated. Results showed that the effect of mulches on soil surface insects changes over time. In both p...
Interest in production of specialty melons is increasing in Florida, particularly among small pro... more Interest in production of specialty melons is increasing in Florida, particularly among small producers and organic growers. However, more research on yield performance and disease resistance of specialty melon cultivars is needed for quality production. In this study, ten specialty melon cultivars were evaluated under both conventional and organic production. Selections include: Ananas melons ‘Creme de la Creme’ and ‘San Juan’; Canary melons ‘Brilliant’ and ‘Camposol’; Asian melons ‘Ginkaku’ and ‘Sun Jewel’; Galia melons ‘Arava’ and ‘Diplomat’; and Honeydew melons ‘Honey Pearl’ and ‘Honey Yellow’. Muskmelon cultivar ‘Athena’ was included for comparison as the standard production melon. Cultivar evaluations were performed in Spring 2011 at the Plant Science Research and Education Unit in Citra, FL. A randomized complete block design was used with 4 replications and 10 plants per cultivar per replication. Harvest date, marketable yield, fruit quality, and disease and root-knot nemato...
Mulching by spreading organic matter around plants has been shown to have an impact on insect pes... more Mulching by spreading organic matter around plants has been shown to have an impact on insect pests by increasing plant tolerance to insects. Also, these help in maintaining soil moisture required for plant vigor and improving soil water and nutrient status for plant growth. A field experiment was conducted to determine the impact of different kinds of mulches (pine bark, or residues of sunnhemp (Crotalaria juncea), sorghum-sudangrass (Sorghum bicolor x S. sudanense), and cowpea (Vigna unguiculata) on the soil surface insect-community. The experiment was laid out in a randomized block design and five replications. Two pitfall traps per plot were examined every two weeks. The number, order and family of the insects found in the traps were recorded. Soil surface insects were also sampled using other methods like wooden boards. Weed and nematode counts and plant stand were also recorded. Data will be presented on the effect of different mulches on insects in traps, weed and nematode co...
In Haiti and other tropical systems, pigeon pea is a valuable rotational crop. As a first step to... more In Haiti and other tropical systems, pigeon pea is a valuable rotational crop. As a first step to evaluate the potential for pigeon pea to be used for multiple purposes in low-external input vegetable systems, this study was conducted to identify the cover crop planting scheme and termination management strategy associated with the greatest cabbage yield and quality when as a rotational cover crop prior to cabbage. The experiment was conducted in Live Oak, Florida at the UF-IFAS North Florida Research and Education Center-Suwannee Valley in 2011 and 2012. Treatments were arranged in a split split-plot design and replicated four times. Main effects included four cover crop (CC) treatments: pigeon pea, (PP); sorghum Sudangrass, (SS); PP and SS biculture (SP); and no cover crop (control). Cover crop plots were equally split in week four after CC emergence with two levels of nitrogen (N): 57 kg ha-1 or 0 kg ha-1 (subplots). Each subplot was equally split again prior to cabbage transplan...
Tropical smallholder farmers operating under low-external-input (LEI) conditions rely upon non-in... more Tropical smallholder farmers operating under low-external-input (LEI) conditions rely upon non-intensive on-farm or locally available inputs for agricultural production; however, conventional resources are limited in the tropics and there is sparse data regarding the sustainability of tropical LEI agroecological systems. The primary objective of these studies is to develop tropical cover crop technologies for use as surface mulch in minimum-till vegetable systems to provide alternative weed management strategies and ensure competitive vegetable yields. Cover crop cultural practices including species selection, seeding date and termination strategies, and the manner in which they influence weed diversity and density as well as vegetable crop yield and quality are the primary issues to define. Vegetable system research conducted in three subtropical/tropical locations (Florida, Puerto Rico and the U.S. Virgin Islands) has resulted in several key lessons concerning LEI systems. Success...
Land Grant University workplace changes necessitate a more systematic, efficient approach to meet... more Land Grant University workplace changes necessitate a more systematic, efficient approach to meeting client needs that includes web-based, nationally coordinated programming. Science-, experience- and regulation-based organic agriculture information must be integrated to produce accurate information of the greatest utility to farmers and agricultural professionals. eOrganic is the organic agriculture Community of Practice for eXtension, the national web initiative for Cooperative Extension and the Land Grant University system. eOrganic works to fill information needs and become an important national source of organic agriculture information by: 1) convening a national community of researchers, extension and other agricultural professionals, farmers, and certifiers at eOrganic.info; 2) facilitating project management, networking and co-learning; 3) supporting collaborative development and publication of peer-reviewed articles, FAQs, and videos at eXtension.org/organic_production; and...
Cultural control practices, including the use of cover crops and mulches, are environmentally saf... more Cultural control practices, including the use of cover crops and mulches, are environmentally safe methods for managing some insect pests and weeds. Several different types of organic mulches were evaluated for effects on soil surface arthropods, weeds, and plant mortality. Field experiments were conducted in fall 2007 and 2008 near Citra, FL. In both seasons, five treatments were compared: cowpea (Vigna unguiculata (L.) Walp.) mulch, sunn hemp (Crotalaria juncea L.) mulch, sorghum-sudangrass (Sorghum bicolor Moench X S. sudanense [Piper] Stapf) mulch, pine bark nuggets, and unmulched control. Mulches were applied around snapdragon (Antirrhinum majus L.) plants in small plots, and treatments arranged in a randomized complete block design with five replications. Data collected included arthropod counts using pitfall traps and board traps, weed ratings, direct counts of buckeye (Junonia coenia Hbner) (Lepidoptera: Nymphalidae) caterpillars, and snapdragon plant mortality. Arthropod gr...
Greenhouse vegetable systems can be certified organic by a United States Department of Agricultur... more Greenhouse vegetable systems can be certified organic by a United States Department of Agriculture accredited certification agency, but these systems are typically focused on transplant production. Higher price premiums associated with greenhouse and certified organic produce (compared with field and conventionally-grown produce) distinguishes organic greenhouse vegetable production as a strong market incentive and a potentially viable, scale-neutral opportunity for growers. Successful non-chemical pest management strategies that have been adopted by greenhouse growers, including biological control, are consistent with the National Organic Program’s Final Rule. However, growing media, fertilizer source and application strategies remain important and challenging issues for organic greenhouse production. The objective of this project was to identify the organic greenhouse nutrient management system that produces the greatest yield and quality of red bell pepper (Capsicum annuum L. ‘X3...
Consumer interest and demand for local foods has changed the dynamic of the Florida small farms i... more Consumer interest and demand for local foods has changed the dynamic of the Florida small farms industry from a little-known group of clientele to a larger and more diverse clientele group that actively participates in University of Florida (UF) extension programming, on-farm research, local and state policy discussions, and partnership building. Based on the USDA definition, well over 90% of the over 47,000 farms in Florida are small farms. Florida reported an 8% increase in farm numbers from 2002 to 2007, essentially all in the small farm category. According to the 2007 US Ag Census, 89% of the Florida farms report less than $100,000 in product sales. The other common characteristic of these operations is they are family-oriented farms dependent upon the family for management and labor. Extension programs can make a difference by providing educational information to help small farmers successfully start their farming operations or adopt new alternative enterprises. Current barrier...
HortScience: a publication of the American Society for Horticultural Science
... for the 2004 growing season, less than 4% of those hectares were managed according to nationa... more ... for the 2004 growing season, less than 4% of those hectares were managed according to national organic standards (K. Hardison, personal communication ... systems indicate the benefits of surface mulch are best realized when the duration of the crop season is long (Hoyt, 1999 ...
The tropical legume sunn hemp (Crotalaria juncea L.) is primarily used a summer cover crop in sou... more The tropical legume sunn hemp (Crotalaria juncea L.) is primarily used a summer cover crop in southeastern vegetable crop production systems. Farmers value sunn hemp for its many benefits to the farming system including rapid growth, high biomass yield, efficient nitrogen (N) fixation, and weed and nematode suppression. Seed is imported from production areas in southern Africa at a cost of $7.00-9.00 kg-1. Cultivars available for purchase are predominantly short-day varieties and consequentially fail to produce adequate seed in the normal period of summer cover crop production (six to eight weeks in Florida). The effects of cultural practices used to manipulate floral initiation and seed production have not been fully examined on biomass production, N sequestration and N mineralization. A 2-year field trial was conducted in the Organic Unit at the UF-IFAS Plant Science Research and Education Unit in Citra, FL to ascertain if managing sunn hemp for seed production would provide addit...
Recirculating greenhouse irrigation is becoming a more common practice for vegetable growers in t... more Recirculating greenhouse irrigation is becoming a more common practice for vegetable growers in the US due to growing concern over freshwater shortages. Utilizing closed loop irrigation systems for greenhouse vegetable production not only saves the grower money due to reduced water and fertilizer use, it also reduces the amount of fertilizers being dispensed into the environment as spent irrigation. One drawback is that water-borne pathogens such as Pythium, Phytopthora, and Fusariam may proliferate in these irrigation systems. To prevent further spread of these pathogens irrigation is disinfected using chemical sanitizers such as chlorine, chlorine dioxide, ozone, and hydrogen peroxide. Chlorine dioxide is advantageous over other widely-used chemical sanitizers because it is active over a wide pH range, it has a high oxidation capacity, and compared to chlorine it doesn’t form carcinogenic halogenated compounds and is effective on organisms resistant to chlorine. Currently there is...
The growth in organic market opportunities has increased the demand across the country for inform... more The growth in organic market opportunities has increased the demand across the country for information on all aspects of organic agricultural production. Until recently, there has been little published Extension information on organic agricultural practices as science-based information was scarce. In addition, science-, experience-, and regulation-based organic agriculture information must be aggregated and integrated to produce information of the greatest utility to farmers and agricultural professionals. eOrganic works to fill this need and become an important national source of organic agriculture information by: 1) convening a national community of researchers, extension and other agricultural professionals, farmers, and certifiers at eOrganic.info; 2) facilitating project management, networking, and co-learning; 3) supporting collaborative development and publication of peer-reviewed articles, FAQs, and videos at eXtension.org/organic_production; and 4) facilitating engagement ...
Recycling greenhouse irrigation water is becoming a popular practice due to water conservation ef... more Recycling greenhouse irrigation water is becoming a popular practice due to water conservation efforts worldwide. However, water must be sanitized prior to recirculation to prevent contamination with plant pathogens. Chlorine dioxide (ClO2), a common disinfectant used to treat municipal water and postharvest dump tanks, has been proposed as a disinfectant for recirculated irrigation systems. Little research has been performed to determine if this chemical is appropriate to use for irrigation on greenhouse specialty crops. The objective of this study was to determine the effects of ClO2 on the vigor of bell pepper plants grown in two different soilless medias (perlite and pine bark). Plants were transplanted in the University of Florida Protected Agriculture Project Greenhouse in Nov. Chlorine dioxide was added to the irrigation solution 11 days after transplanting at concentrations of 0, 10, 20 and 40 ppm. Relatively high concentrations were used to estimate an upper threshold for p...
Mulching by spreading organic matter around plants has been shown to increase plant tolerance to ... more Mulching by spreading organic matter around plants has been shown to increase plant tolerance to insect pests. Also, mulches help in maintaining soil moisture required for plant vigor and thus improve soil water and nutrient status for plant growth. A field experiment was conducted to determine the impact of different kinds of mulches (pine bark, sunn hemp (Crotalaria juncea), sorghum-sudangrass (Sorghum bicolor x S. sudanense), cowpea (Vigna unguiculata), or non-mulched control) on the soil surface insect community. The five treatments were replicated five times in a randomized block design. Insects were evaluated every two weeks using two pitfall traps per plot. Soil surface insects were also sampled using other methods such as wooden board traps. The total number, order, and family of all arthropods found in the traps were recorded. Weeds, nematodes, and plant stand were also evaluated. Results showed that the effect of mulches on soil surface insects changes over time. In both p...
Interest in production of specialty melons is increasing in Florida, particularly among small pro... more Interest in production of specialty melons is increasing in Florida, particularly among small producers and organic growers. However, more research on yield performance and disease resistance of specialty melon cultivars is needed for quality production. In this study, ten specialty melon cultivars were evaluated under both conventional and organic production. Selections include: Ananas melons ‘Creme de la Creme’ and ‘San Juan’; Canary melons ‘Brilliant’ and ‘Camposol’; Asian melons ‘Ginkaku’ and ‘Sun Jewel’; Galia melons ‘Arava’ and ‘Diplomat’; and Honeydew melons ‘Honey Pearl’ and ‘Honey Yellow’. Muskmelon cultivar ‘Athena’ was included for comparison as the standard production melon. Cultivar evaluations were performed in Spring 2011 at the Plant Science Research and Education Unit in Citra, FL. A randomized complete block design was used with 4 replications and 10 plants per cultivar per replication. Harvest date, marketable yield, fruit quality, and disease and root-knot nemato...
Mulching by spreading organic matter around plants has been shown to have an impact on insect pes... more Mulching by spreading organic matter around plants has been shown to have an impact on insect pests by increasing plant tolerance to insects. Also, these help in maintaining soil moisture required for plant vigor and improving soil water and nutrient status for plant growth. A field experiment was conducted to determine the impact of different kinds of mulches (pine bark, or residues of sunnhemp (Crotalaria juncea), sorghum-sudangrass (Sorghum bicolor x S. sudanense), and cowpea (Vigna unguiculata) on the soil surface insect-community. The experiment was laid out in a randomized block design and five replications. Two pitfall traps per plot were examined every two weeks. The number, order and family of the insects found in the traps were recorded. Soil surface insects were also sampled using other methods like wooden boards. Weed and nematode counts and plant stand were also recorded. Data will be presented on the effect of different mulches on insects in traps, weed and nematode co...
In Haiti and other tropical systems, pigeon pea is a valuable rotational crop. As a first step to... more In Haiti and other tropical systems, pigeon pea is a valuable rotational crop. As a first step to evaluate the potential for pigeon pea to be used for multiple purposes in low-external input vegetable systems, this study was conducted to identify the cover crop planting scheme and termination management strategy associated with the greatest cabbage yield and quality when as a rotational cover crop prior to cabbage. The experiment was conducted in Live Oak, Florida at the UF-IFAS North Florida Research and Education Center-Suwannee Valley in 2011 and 2012. Treatments were arranged in a split split-plot design and replicated four times. Main effects included four cover crop (CC) treatments: pigeon pea, (PP); sorghum Sudangrass, (SS); PP and SS biculture (SP); and no cover crop (control). Cover crop plots were equally split in week four after CC emergence with two levels of nitrogen (N): 57 kg ha-1 or 0 kg ha-1 (subplots). Each subplot was equally split again prior to cabbage transplan...
Tropical smallholder farmers operating under low-external-input (LEI) conditions rely upon non-in... more Tropical smallholder farmers operating under low-external-input (LEI) conditions rely upon non-intensive on-farm or locally available inputs for agricultural production; however, conventional resources are limited in the tropics and there is sparse data regarding the sustainability of tropical LEI agroecological systems. The primary objective of these studies is to develop tropical cover crop technologies for use as surface mulch in minimum-till vegetable systems to provide alternative weed management strategies and ensure competitive vegetable yields. Cover crop cultural practices including species selection, seeding date and termination strategies, and the manner in which they influence weed diversity and density as well as vegetable crop yield and quality are the primary issues to define. Vegetable system research conducted in three subtropical/tropical locations (Florida, Puerto Rico and the U.S. Virgin Islands) has resulted in several key lessons concerning LEI systems. Success...
Land Grant University workplace changes necessitate a more systematic, efficient approach to meet... more Land Grant University workplace changes necessitate a more systematic, efficient approach to meeting client needs that includes web-based, nationally coordinated programming. Science-, experience- and regulation-based organic agriculture information must be integrated to produce accurate information of the greatest utility to farmers and agricultural professionals. eOrganic is the organic agriculture Community of Practice for eXtension, the national web initiative for Cooperative Extension and the Land Grant University system. eOrganic works to fill information needs and become an important national source of organic agriculture information by: 1) convening a national community of researchers, extension and other agricultural professionals, farmers, and certifiers at eOrganic.info; 2) facilitating project management, networking and co-learning; 3) supporting collaborative development and publication of peer-reviewed articles, FAQs, and videos at eXtension.org/organic_production; and...
Cultural control practices, including the use of cover crops and mulches, are environmentally saf... more Cultural control practices, including the use of cover crops and mulches, are environmentally safe methods for managing some insect pests and weeds. Several different types of organic mulches were evaluated for effects on soil surface arthropods, weeds, and plant mortality. Field experiments were conducted in fall 2007 and 2008 near Citra, FL. In both seasons, five treatments were compared: cowpea (Vigna unguiculata (L.) Walp.) mulch, sunn hemp (Crotalaria juncea L.) mulch, sorghum-sudangrass (Sorghum bicolor Moench X S. sudanense [Piper] Stapf) mulch, pine bark nuggets, and unmulched control. Mulches were applied around snapdragon (Antirrhinum majus L.) plants in small plots, and treatments arranged in a randomized complete block design with five replications. Data collected included arthropod counts using pitfall traps and board traps, weed ratings, direct counts of buckeye (Junonia coenia Hbner) (Lepidoptera: Nymphalidae) caterpillars, and snapdragon plant mortality. Arthropod gr...
Greenhouse vegetable systems can be certified organic by a United States Department of Agricultur... more Greenhouse vegetable systems can be certified organic by a United States Department of Agriculture accredited certification agency, but these systems are typically focused on transplant production. Higher price premiums associated with greenhouse and certified organic produce (compared with field and conventionally-grown produce) distinguishes organic greenhouse vegetable production as a strong market incentive and a potentially viable, scale-neutral opportunity for growers. Successful non-chemical pest management strategies that have been adopted by greenhouse growers, including biological control, are consistent with the National Organic Program’s Final Rule. However, growing media, fertilizer source and application strategies remain important and challenging issues for organic greenhouse production. The objective of this project was to identify the organic greenhouse nutrient management system that produces the greatest yield and quality of red bell pepper (Capsicum annuum L. ‘X3...
Consumer interest and demand for local foods has changed the dynamic of the Florida small farms i... more Consumer interest and demand for local foods has changed the dynamic of the Florida small farms industry from a little-known group of clientele to a larger and more diverse clientele group that actively participates in University of Florida (UF) extension programming, on-farm research, local and state policy discussions, and partnership building. Based on the USDA definition, well over 90% of the over 47,000 farms in Florida are small farms. Florida reported an 8% increase in farm numbers from 2002 to 2007, essentially all in the small farm category. According to the 2007 US Ag Census, 89% of the Florida farms report less than $100,000 in product sales. The other common characteristic of these operations is they are family-oriented farms dependent upon the family for management and labor. Extension programs can make a difference by providing educational information to help small farmers successfully start their farming operations or adopt new alternative enterprises. Current barrier...
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Papers by Danielle Treadwell