Okra (Abelmoschus esculentus) is grown as a direct-seeded cash crop at high plant populations (>87,000 plants/acre) on calcareous soils in Homestead, south Florida. A study was established in a commercial field in May 2005 to evaluate if high populations translated to higher yields. Seedlings were thinned to within-row spacings of 2, 4, 6, 8, and 10 inches in rows set 3 ft apart (87120, 43560, 29040, 21780, and 17420 plants/acre). Harvest data was collected from 29 July to 30 Sept. 2005 (26 harvests) from 10 ft of the center row within plots 15 ft long and 3 rows wide. Decreasing plant density resulted in decreasing plant height early in the season and increasing height late in the season. Density affected stem caliper with a clear trend of decreasing density and increasing caliper. Early, mid-, and total yields by weight (boxes/acre) were not affected by density, but plants at the lowest density produced 55% more late yield than plants at the highest density. Plants at the lowest density produced 30% fewer early pods and 31% more late pods than plants at the highest density. Decreasing plant density resulted in increasing average pod weight for early, late, and total harvests by as much as 14% to 18%. With inexpensive open pollinated cultivars such as `Clemson Spineless 80', there seems little economic incentive to reduce plant populations below what is commonly used in the Homestead area. Growers should not be alarmed, however, if plant stands are reduced to some extent after seeding.
Teresa Olczyk, Kent Cushman and Waldemar Klassen
Teresa Olczyk, Yuncong Li, Waldemar Klassen and Qingren Wang
Summer cover crops can improve soil fertility by adding organic matter, supplying nutrients through mineralization, reducing nutrient leaching, and improving soil water and nutrient holding capacity. Other benefits include weed suppression and reduction of soil parasitic nematodes. A series of field experiments have been conducted at the UF IFAS Tropical Research and Education Center in Homestead, Florida to evaluate several summer cover crops for use in vegetable production in South Florida followed by field demonstrations conducted in the growers' fields. Best performing cover crops were legumes: velvet bean (Macuna deeringiana) and sunn hemp (Crotalaria juncea L. `Tropic Sun') providing 13 and 11 Mt of dry matter/ha, respectively. Sunn hemp supplied 330 kg N/ha followed by velvet been with 310 kg N/ha. Traditional summer cover crop sorghum-Sudan produced 4 Mt of dry matter/ha and retained only 36 kg N/ha. In addition Sunn hemp significantly reduced soil parasitic nematodes for successive crops. Limitations in use of Sunn hemp by more vegetable growers in South Florida include cost and availability of seeds.
Mary Lamberts*, Eugene McAvoy, Teresa Olczyk and Phyllis Gilreath
U.S. agricultural producers are required to provide varying amounts of safety training to their employees depending on the nature of their operation(s). Hand washing is an integral part of several types of safety training including pesticide safety education, the Worker Protection Standard and Microbial Food Safety of Fruits and Vegetables. Generally instructions are to “wash thoroughly,” though some employees are told they should wash for 20 seconds. An easy way to get growers to “buy into” methods that verify hand washing is to include such demonstrations as part of pesticide safety education programs and workshops that grant Continuing Education Units (CEUs) for the renewal of pesticide applicator licenses. It is important that the demonstrations be highly visual so participants actually experience the difficulty in removing a contaminant from hands even though they have performed “thorough” hand washing. It also allows them to observe the ease of cross contamination from soiled hands. Once growers see how easy and inexpensive it is to do this type of training, they are being encouraged to use these demonstrations with various types of employees: mixer-loaders and other handlers, harvesting crews, packinghouse employees, and even field workers who routinely handle plants and may be spreading diseases. Details on different methods of training and grower reactions will be presented.
Teresa Olczyk, Yuncong Li, Xing Wang and Eric Simonne
Sweet corn (Zea mays) is a major cash crop produced on calcareous soils in Miami–Dade County. Applications of large amounts of phosphorus (P) fertilizer for many years resulted in the accumulation of high levels of P in these soils. Accumulated P is slowly released into the soil solution to become available for plant roots. Previous studies conducted in this area showed little or no yield and crop quality response to P fertilizer applications. Large-scale field trials with reduced P applications were conducted in a grower's field. The treatments were: 1) no P; 2) 50% grower's rate; and 3) 100% grower's rate with six repilications. The data collected included: plant stand, height, nutrient concentrations in leaf tissue, leaf chlorophyll, tip fill, number, and weight of marketable ears/acre. Reduced rates of P fertilizer did not significantly reduce yield and quality of sweet corn.
Teresa Olczyk, Juanita Popenoe, Ed Skvarch and Alejandro Bolques
The Florida nursery industry generated $3 billion in farm gate sales in 2005, positioning Florida as the nation's second largest nursery crop production state after California. The recent downturn in the economy and collapse of the housing market has had a negative impact on some sectors of the industry, forcing many of the nurseries producing landscape plant material out of business, but leaving some nurseries untouched. An informal survey by extension agents indicated that nurseries are coping by using various strategies, including reductions in labor force, increased efficiencies in irrigation and fertilizer, the adoption of best management practices, creative marketing strategies, specialization in the production of unique crops, and innovative production and business techniques.
Kent Cushman, Monica Ozores-Hampton, Eric Simonne, Eugene McAvoy, Darrin Parmenter and Teresa Olczyk
Vegetable producers in south Florida suffered the effects of four major hurricanes during 2004 and two during 2005, causing damage to crops and farms estimated at well over 1 billion dollars each year. Producers were quick to respond by replanting or nursing damaged crops back to health. Green beans and leafy crops appeared least likely to recover or produce acceptable yields after exposure to high winds and driving rains. Young tomato plants up to the second or third string were at times completely stripped of leaf material, yet recovered surprisingly quickly. A replant study showed no benefit in replanting compared to keeping damaged plants in the field. Older tomato plants were marginal in their ability to recover with 10% to 60% reductions in yield for first and second harvests when compared to yields common in the region. As much as 100% of Palm Beach County's 2005 early fall bell pepper planting was destroyed by storms. Other peppers in the region were affected by flooding and subsequent development of root diseases such as phytophthora. Damaged eggplant recovered slowly. Research plantings located in commercial fields and at Research and Education Centers were devastated. In addition to loss of crops, costs to vegetable growers included labor to remove damaged plastic and reset stakes, installation of replacement plastic mulches, replanting, and structural damage to buildings and packing facilities. Some transplant houses and greenhouses for specialty peppers were completely destroyed. Removing plastic coverings before a storm's arrival saved structures and crops. Transplants of all crops were in short supply. Labor was lacking due to reconstruction efforts in New Orleans and the Gulf Coast. Successful and not-so-successful recovery efforts will be shown.
B.T. Scully, R.L. Beiriger, Teresa Olczyk and J.R. Stavely
Mary Lamberts, Teresa Olczyk, Stephen K. O'Hair, Juan Carranza, Herbert H. Bryan, Edward Hanlon and George Hochmuth
A baseline survey was conducted to determine grower fertilizer management practices for five vegetable crops: beans, malanga, potatoes, sweet corn, and squash. This was done in conjunction with a 3-year replicated fertility trial with four vegetable crops (1993–94 through 1995–96) in the Homestead area. Questions included: fertilizer rates and timing, source(s) of fertilizer recommendations, soil and tissue testing, irrigation, changes in practices, summer cover crops, rock plowing, spacing, and type of fertilizer used. Survey results will be presented.
Mary Lamberts, Teresa Olczyk, Stephen K. O'Hair, Juan Carranza, Herbert H. Bryan, George Hochmuth and Edward Hanlon
Replicated fertility trials with four vegetable crops on the limestone soils of Dade County, Fla., have been conducted for 3 years (1993–94 through 1995–96). The purpose was 1) to determine crop nutrient requirements, 2) to calibrate a soil testing model, and 3) to develop additional information for plant sap quick tests. The crops included snap beans, Irish potatoes, sweet corn, and malanga (a.k.a. yautia or tannia, Xanthosoma sagittifolium Schott). Another two field demonstrations using reduced rates of phosphorus on tomatoes were conducted in 1995–96. The involvement of the local fertilizer industry in these trials and grower outreach efforts will be discussed.
Mary Lamberts, Teresa Olczyk, Phyllis Gilreath, Gene McAvoy, Alicia Whidden, Darrin Parmenter, Ed Skvarch, Yuncong Li, Christine Coffin and Donald Pybas
Florida, like other states, is developing BMPs for specific commodities. Vegetables are in a statewide document that includes field crops. Vegetable advisory committee members from the counties in southern Florida were concerned that the existing document was too broad in its scope and that many practices did not apply to production on sandy or calcareous soils. Based on grower comments, extension agents organized grower meetings to address these issues. The first meeting was a presentation by the Florida Department of Agriculture and Consumer Services (FDACS) Office of Agricultural Water Policy. The second meeting in Miami–Dade was a hands-on session, where growers and industry were divided into three areas—nutrition, pesticides, and water quality. Each group was facilitated by a faculty member or the NRCS conservationist. Other counties used newsletters and other methods to receive grower feedback. Participant comments were compiled and forwarded to FDACS, where they are being incorporated into a greatly revised document. Concerns will be presented.