Two field comparisons of conservation tillage tomato production alternatives following wheat were conducted in California's Central Valley. Both studies compared: 1) standard tillage; 2) bed disk or permanent bed minimum tillage; and 3) strip-tillage following winter wheat crops that were harvested the previous June. Processing tomatoes were produced at the site in Davis, Calif., and fresh market tomatoes were grown in Parlier, Calif. At both sites, establishing tomatoes using a commercial transplanter or a modified conservation tillage transplanter achieved adequate stands even in the minimally-tilled strip-till system. Timing of the strip till operation, however, is critical so that large chuncks of dry soil are not brought up and so that these do not create very rough bed surfaces that may cause harvest problems, particularly for processing tomatoes. Machine harvesting the crop at the Davis site did not seem to create any mechanical difficulties or generate additional trash going into the harvest trailer. This may have been due to the fact that by harvest time, the majority of the surface residue from the previous wheat crop had already been broken down or at least sufficiently worked into the soil to pose minimal mechanical harvester impedance or contamination. Tomato yields for the reduced till systems equalled yields of the standard till systems at both sites.
Jeffrey P. Mitchell*, Gene M. Miyao, Jim J. Jackson, Lee F. Jackson, Tom Lanini, Charlie G. Summers, and Jim J. Stapleton
Pamela D. Adams, Nancy Kokalis-Burelle, and William H. Basinger
Plantpro 45, an iodine-based compound, was evaluated as a seed treatment for management of fusarium wilt caused by Fusarium oxysporum f.sp. basilici on basil (Ocimum basilicum) in greenhouse assays and for effects on growth of the pathogen in vitro. Plantpro 45 at a concentration of 300 mg·L-1 (ppm) prevented fusarium hyphal growth in vitro. Seed treatments of 800 to 1000 mg·L-1 eliminated fungal contamination of seed and increased germination by 27% compared to the nontreated control. Basil transplants grown from seed treated with 400, 800, and 1000 mg·L-1 were significantly taller, weighed more, exhibited larger leaf area, and had reduced wilt severity in the greenhouse compared to the nontreated control. Transplants grown in soil treated with increasing concentrations of Plantro 45 had correspondingly decreased wilt severity, regardless of whether or not the seeds had been previously treated with Plantpro 45. Further research and optimization of soil and foliar applications in combination with seed treatments are needed to provide a complete program for management of fusarium wilt of basil.
H.H. Krusekopf, J.P. Mitchell, T.K. Hartz, D.M. May, E.M. Miyao, and M.D. Cahn
Overuse of chemical N fertilizers has been linked to nitrate contamination of both surface and ground water. Excessive use of fertilizer also is an economic loss to the farmer. Typical N application rates for processing tomato (Lycopersicon esculentum Mill.) production in California are 150 to 250 kg·ha-1. The contributions of residual soil NO3-N and in-season N mineralization to plant nutrient status are generally not included in fertilizer input calculations, often resulting in overuse of fertilizer. The primary goal of this research was to determine if the pre-sidedress soil nitrate test (PSNT) could identify fields not requiring sidedress N application to achieve maximum tomato yield; a secondary goal was to evaluate tissue N testing currently used for identifying post-sidedress plant N deficiencies. Field experiments were conducted during 1998 and 1999. Pre-sidedress soil nitrate concentrations were determined to a depth of 60 cm at 10 field sites. N mineralization rate was estimated by aerobic incubation test. Sidedress fertilizer was applied at six incremental rates from 0 to 280 kg·ha-1 N, with six replications per field. At harvest, only four fields showed a fruit yield response to fertilizer application. Within the responsive fields, fruit yields were not increased with sidedress N application above 112 kg·ha-1. Yield response to sidedress N did not occur in fields with pre-sidedress soil NO3-N levels >16 mg·kg-1. Soil sample NO3-N levels from 30 cm and 60 cm sampling depth were strongly correlated. Mineralization was estimated to contribute an average of 60 kg·ha-1 N between sidedressing and harvest. Plant tissue NO3-N concentration was found to be most strongly correlated to plant N deficiency at fruit set growth stage. Dry petiole NO3-N was determined to be a more accurate indicator of plant N status than petiole sap NO3-N measured by a nitrate-selective electrode. The results from this study suggested that N fertilizer inputs could be reduced substantially below current industry norms without reducing yields in fields identified by the PSNT as having residual pre-sidedress soil NO3-N levels >16 mg·kg-1 in the top 60 cm.
L. Carolina Medina, Thomas A. Obreza, Jerry B. Sartain, and Robert E. Rouse
Most Florida citrus is grown on extremely sandy soils inherently low in fertility, cation exchange capacity, and ability to retain applied plant nutrients. Traditionally, the main way of providing nitrogen (N) to Florida citrus trees has been
Allen V. Barker
materials and have been altered drastically by anthropogenic activities. They explain that in general urban soils are not favorable to plant growth due to compaction and contamination. The book addresses the poor quality and presents discussions of food
Anne Plotto and Jan A. Narciso
Organic foods are produced using agricultural practices that emphasize renewable resources and conservation of soil and water. Horticultural crops are grown and processed without synthetic fertilizers, pesticides, ingredients and processing aids. Crops or ingredients derived from genetic engineering, and use of ionizing radiation are prohibited in organic production. The challenge is to deliver produce that has the same safety, quality and shelf life as conventional products, with a limited array of tools available for sanitation and postharvest treatments. Organic operators, professionals servicing the industry, as well as researchers involved in organic production practices, should be aware of all the points in the process of storing, handling and transforming horticultural crops where accidental contamination could occur, and thus compromise organic integrity. This presentation summarizes the major points of the National Organic Program for processing and handling, and gives suggestions for postharvest research. For example, finding organic alternatives for postharvest decay control is critical to maintain food safety. Additionally, ingredients compatible for fresh cut and produce coatings must be developed for the organic market for food safety and competitiveness.
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.
Michael D. Orzolek and John H. Murphy
A long term study was initiated in 1993 to evaluate the effect of composted sewage sludge on growth, yield, and quality of different vegetables. The composted sewage sludge consisting of 40% hardwood sawdust and 60% clean municipal wastewater sludge was obtained from the University Area Joint Authority (UAJA) in State College, PA. The composted sewage sludge is currently sold by UAJA as a fertilizer amendment under the name CornposT. Two rates of the ComposT product (11 and 22 dry T/A) were compared to a granular fertilizer application of 800 lbs/A of 10-10-10. The low rate of ComposT also received half of the fertilizer rate. After incorporation of the amendments into a Hagerstown clay loam soil, lettuce, tomato, muskmelon, cabbage and pepper were transplanted in the field in a Randomized Block Design with 3 replications. ComposT application did not reduce yield or quality of cabbage, lettuce tomato,and muskmelon; in fact, yields were generally higher with the application of composted sewage sludge. The application of ComposT did not reduce the macro or micro nutrient concentration of leaf tissue below optimum levels nor did it result in any phytotoxic effects in plant growth. In addition, the application of ComposT did not increase the heavy metal (Cd, Ni, Pb) concentration in leaf tissue or increase the risk of microbial contamination in the edible portion of the vegetables.
W.H. Tietien, P. Nitzsche, and W.P. Cowgill Jr.
Environmental concerns about nitrate contamination of groundwater have prompted renewed interest in optimizing fertilizer rates. A field study was initiated to study the influence of preplant and drip fertigation rates of nitrogen on the yield of hell peppers grown on Quakertown (QkB) silt loam soil. Preplant nitrogen rates of 0, 56.7, and 113.5 kgha were incorporated into the plots before transplanting. The three fertigation rates (0, 17 and 34 Kg/mulched hectare) were injected through the drip irrigation starting one week after transplanting and repeated at three week intervals.
Proplant nitrogen applications variably influenced early pepper yield. and did not significantly influence total yield. Early pepper yield was not influenced by drip fertigation rate, however, total yield increased as the fertigation rate increased. The dry weather conditions of the 1993 growing season may have influenced the responsc of pepper yield to the fertilizer treatments. Further studies are required to determine the optimum fertilization program for bell peppers grown under Northern New Jersey's edaphic conditions.
Carl J. Rosen, Thomas R. Halbach, and Bert T. Swanson
Composting of municipal solid waste (MSW) has received renewed attention as a result of increasing waste disposal costs and the environmental concerns associated with using landfills. Sixteen MSW composting facilities are currently operating in the United States, with many more in the advanced stages of planning. A targeted end use of the compost is for horticultural crop production. At the present time, quality standards for MSW composts are lacking and need to be established. Elevated heavy metal concentrations in MSW compost have been reported; however, through proper sorting and recycling prior to composting, contamination by heavy metals can be reduced. Guidelines for safe metal concentrations and fecal pathogens in compost, based on sewage sludge research, are presented. The compost has been shown to be useful in horticultural crop production by improving soil physical properties, such as lowering bulk density and increasing water-holding capacity. The compost can supply essential nutrients to a limited extent; however, supplemental fertilizer, particularly N, is usually required. The compost has been used successfully as a sphagnum peat substitute for container media and as a seedbed for turf production. High soluble salts and B, often leading to phytotoxicity, are problems associated with the use of MSW compost. The primary limiting factor for the general use of MSW compost in horticultural crop production at present is the lack of consistent, high-quality compost.