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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.

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Robin G. Brumfield

Since World War II, U.S. agriculture has reduced production costs by substituting petrochemicals for labor. Adverse impacts from chemical intensive agriculture include increased pest levels, groundwater and surface water contamination, soil erosion, and concerns about harmful levels of pesticide residues. Sustainable farming programs such as integrated crop management (ICM) and organic farming encourage farmers to use systems that reduce the adverse impacts of chemical agriculture. However, before farmers adopt an alternative system, they must determine that economic benefits from the alternative farming activities exceed the costs incurred. Unfortunately, relatively few studies have compared the cost of organic crop production with conventional production systems. Results of these studies are mixed. In some studies, organic systems are more profitable than conventional systems with organic price premiums, but are not economically viable without price premiums. In one long-term study, the organic system was more profitable than a conventional one if the cost of family labor was ignored, but less profitable if it was included. In some studies, net returns were higher for ICM than for conventional or organic systems, but in others, they were higher. Results also vary on a crop by crop basis.

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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.

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Clinton C. Shock, Erik B. G. Feibert, and Lamont D. Saunders

Onion (Allium cepa L.) production in the Treasure Valley of eastern Oregon and southwestern Idaho has been based on furrow irrigation with 318 kg·ha-1 N fertilizer and average yields of 70 Mg·ha-1, but these practices have been implicated in nitrate contamination of groundwater. Drip irrigation, introduced in the early 1990s, has several advantages, including reduced leaching losses. Since onion plant populations and N fertilizer rates can affect economic returns, studies were conducted in 1999, 2000, and 2001 to determine optimum plant populations and N fertilizer rates for subsurface drip-irrigated onion. Long-day onion (`Vision') was subjected to a combination of seven nitrogen fertilization rates (0 to 336 kg·ha-1 in 56-kg increments applied between late May and early July) and four plant populations (185, 250, 300, and 370 thousand plants/ha). Onion was grown on silt loam in two double rows spaced 0.56 m apart on 1.1 m beds with a drip tape buried 13 cm deep in the bed center. Soil water potential was maintained nearly constant at -20 kPa by automated irrigations based on soil water potential measurements at a 0.2-m depth. Onion bulbs were evaluated for yield and grade after 70 days of storage. Onion yield and grade were highly responsive to plant population. Onion marketable yield increased, and bulb diameter decreased with increasing plant population. Within the range of plant populations tested, gross returns were not always responsive to plant population. Returns were increased by the increase in marketable yield obtained with higher plant population, but higher plant population also reduced the production of the largest sized bulbs which had the highest value per weight. Onion yielded 95 Mg·ha-1 with no applied N fertilizer, averaged over plant populations and years. Onion yield and grade were not responsive to N fertilizer rate or interaction of N fertilizer rate with plant population. Preplant soil available N, N mineralization, and N in irrigation water all contributed N to the crop. Onion N uptake did not increase with increasing N fertilizer rate.

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Peter J. Landschoot, Bradley S. Park, Andrew S. McNitt, and Michael A. Fidanza

Fumigation of annual bluegrass (Poa annua L.)-infested putting greens before seeding creeping bentgrass (Agrostis stolonifera L.) prevents stand contamination due to annual bluegrass seedling emergence. Dazomet is a soil fumigant labeled for use in putting green renovation; however, limited data are available on efficacy of dazomet controlling annual bluegrass seedling emergence following surface-applications. The objectives of this study were to determine the influence of rate and plastic covering of surface-applied dazomet on annual bluegrass seedling emergence in putting green turf; and safe creeping bentgrass seeding intervals following applications of dazomet to putting green surfaces. Treatments were applied in late summer to the surface of a 20-year-old stand of turf maintained as a putting green and plots were watered immediately after application and throughout each test period. Plastic-covered dazomet treatments had fewer annual bluegrass seedlings than noncovered dazomet treatments. Three plastic-covered dazomet treatments (291, 340, and 388 kg·ha-1) provided complete control of annual bluegrass seedlings during 2000 and 2001. None of the noncovered dazomet treatments provided complete control of annual bluegrass seedling emergence. Results of the seeding interval experiment revealed that creeping bentgrass seedling development was not inhibited in both plastic-covered and noncovered dazomet treatments, when seeded 8, 10, 13, and 16 d after dazomet was applied to the turf surface. Results of this study demonstrate that dazomet, applied at rates ≥291 kg·ha-1 to the surface of a putting green in summer and covered with plastic for 7 d, can control annual bluegrass seedling emergence. Chemical name used: tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione (dazomet).

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Lincoln Zotarelli, Johannes Scholberg, Michael Dukes, Hannah Snyder, Eric Simonne, and Michael Munoz-Carpena

On sandy soils, potential N contamination of groundwater resources associated with intensively managed vegetables may hamper the sustainability of these systems. The objective of this study was to evaluate the interaction between irrigation system design/scheduling and N fertilization rates on zucchini production and potential N leaching. Zucchini was planted during Fall 2005 using three N fertilizer rates (73, 145, 217 kg/ha) and four different irrigation approaches. Irrigation scheduling included surface-applied drip irrigation and fertigation: SUR1 (141 mm applied) and SUR2 (266 mm) using irrigation control system (QIC) that allowed time-based irrigation (up to five events per day) and a threshold setting of 13% and 15% volumetric water content (VWC), respectively; Subsurface drip irrigation (SDI) using a QIC setting of 10% VWC (116 mm) combined with surface applied fertigation; and a control treatment with irrigation applied once daily (424 mm). Leacheate volumes were measured by drainage lysimeters. Nitrate leaching increased with irrigation rate and N rate and measured values ranged from 4 to 42 kg N/ha. Use of SDI greatly reduced nitrate leaching compared to other treatments. SDI and SUR1 treatments had no effect on yields (29 Mg/ha). However, SDI had a 15% and 479% higher water use efficiency (WUE) compared to SUR1 and the fixed irrigation duration treatment. Application of N in excess of intermediate N-rate (standard recommendation) did not increase yield but yield was reduced at the lowest N-rate. It is concluded that combining sensor-based SDI with surface applied fertigation resulted similar or higher yields while it reduced both water use and potential N leaching because of improved nutrient retention in the active root zone.

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Yun-wen Wang, Bruce L. Dunn, and Daryl B. Arnall

(CRD). Normalized Difference Vegetation Index, Soil-Plant Analyses Development value, and nitrogen content determination. Normalized Difference Vegetative Index readings were collected 42 and 48 d after initial fertilizer treatment (DAT) using a NDVI

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Danielle D. Treadwell, George J. Hochmuth, Robert C. Hochmuth, Eric H. Simonne, Lei L. Davis, Wanda L. Laughlin, Yuncong Li, Teresa Olczyk, Richard K. Sprenkel, and Lance S. Osborne

to soil 90 d in advance of crops with harvested portions that do not touch the soil and 120 d in advance of harvested portions that do touch the soil. Many studies have been conducted on the use of compost as a media supplement in greenhouse

Open access

Meredith V. Melendez, Joseph R. Heckman, Stephanie Murphy, and Frank D’Amico

contamination. 20 Jan. 2020. < > U.S. Environmental Protection Agency 2007 Method 6200: Field portable x-ray fluorescence spectrometry for the determination of elemental concentrations in soil

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Mary C. Stevens, Rui Yang, and Joshua H. Freeman

Due to the ban on methyl bromide (MBr), the efficacy of old and new soil fumigants have been examined and developed further. A novel soil fumigant not currently labeled in the United States, ethanedinitrile (EDN), was initially examined for use as a