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Timothy K. Hartz and Thomas G. Bottoms

. In a greenhouse experiment, these products were evaluated for their effects on lettuce seedling emergence, growth, and P uptake. Four soils were collected from California fields in vegetable crop rotations, chosen for their limited P availability

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K.M. Batal, M.R. Hall, D.M. Granberry, J.T. Garrett, D.R. Decoteau, R.T. Dufault, G.D. Hoyt, T.C. Gilsanz, J.M. Davis, and D.C. Sanders

Vegetable Crops

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A. G. Taylor and C. W. Ten Broeck

Abstract

Individual seedling emergence forces were determined for nine vegetable crops with an universal testing instrument (Model TTCM Instron). The seed energy content also was calculated with an oxygen bomb calorimeter. Seed weights of the different crops were correlated with seedling forces and the seed energy content. The time required to achieve the maximum force varied among crops and the pressure exerted varied from 26 mN for table beet (Beta vulgaris L.) to 3400 mN for snap bean (Phaseolus vulgaris L.). Equipment was developed to measure the combined seedling emergence forces of 50 seedlings. Snap bean seeds were sized into three groups: 200, 275, and 350 mg per seed. Total force, percent seedling emergence, force per seedling, pressure exerted, and energy content increased in a linear trend as seed size increased. An inverse relation existed between the capacity of seeds to use reserve materials and seed size. Small-sized seeds were more efficient in using reserve materials than large ones.

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Monica Ozores-Hampton, Thomas A. Obreza, and George Hochmuth

Large volumes of compost produced from waste materials like yard trimmings, household trash (municipal solid waste), or biosolids (wastewater sludge) will likely become available for use by the Florida vegetable industry in the future. Using compost to produce vegetables has the potential to increase water and fertilizer conservation and reduce leaching from inorganic fertilizers in Florida's sandy soils. Compost quality for vegetable production systems should be based on soluble salts, phytotoxic compounds, C:N ratio, plant nutrients, trace metals, weed seeds, odor, moisture, pH, water-holding capacity, bulk density, cation exchange capacity, and particle size. In Florida, immature compost contained phytotoxic compounds that were harmful to crop germination and growth. Amending soil with mature composted waste materials has been reported to increase the growth and yields of vegetable crops grown in Florida. However, a beneficial response does not always occur, and the magnitude of the response is often not predictable.

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Edwin Kee and Tracy Wootten

U.S. crop loss from hail damage amounted to $246,443,391 in 1991. Premiums paid for hail insurance was $403,742,507. Despite the magnitude of this industry, the effects of varying levels of hail injury at different stages of plant growth is largely unknown for many vegetable crops. To further evaluate the effects of hail on strawberries, watermelons, and sweet corn, several studies were established in 1991 and 1992. Simulated hail applications were made at different rates and stages of crop growth. Total yields and marketable yields of strawberries were reduced by hail applications. All hail treatments reduced the number of marketable watermelons, except for the vegetative size light hail treatment in 1991. In 1992, the early treatments caused the most total yield reduction. All hail treatments reduced the percentage of marketable ears of sweet corn, except for the light application in the 13th leaf stage (early vegetative) in 1991. In 1992, additional treatments consisting of clipping all leaves were conducted. Clipping leaves at the early silking stage reduced marketable ears, indicating the loss of foliage adversely affected the growth of the ear. Clipping leaves just prior to harvest reduced the yield of Jubilee, but not Silver Queen.

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M.J. Haar, S.A. Fennimore, M.E. McGiffen, W.T. Lanini, and C.E. Bell

In an effort to identify new herbicides for vegetables crops, broccoli (Brassica oleracea) cantaloupe (Cucumis melo), carrot (Daucus carota), head lettuce (Lactuca sativa), bulb onion (Allium cepa), spinach (Spinacia oleracea) and processing tomato (Lycopersicon esculentum) were evaluated in the field for tolerance to eight herbicides. The following herbicides and rates, expressed in a.i. lb/acre, were applied preemergence: carfentrazone, 0.05, 0.1, 0.15 and 0.2; flufenacet, 0.525; flumioxazin, 0.063, 0.125 and 0.25; halosulfuron, 0.032 and 0.047; isoxaben, 0.25 and 0.50; rimsulfuron, 0.016 and 0.031; SAN 582, 0.94 and 1.20 and sulfentrazone, 0.15 and 0.25 (1.000 lb/acre = 1.1208 kg·ha-1). Tolerance was evaluated by measuring crop stand, injury and biomass. Several leads for new vegetable herbicides were identified. Lettuce demonstrated tolerance to carfentrazone at 0.05 and 0.10 lb/acre. Cantaloupe and processing tomato were tolerant of halosulfuron at 0.032 and 0.047 lb/acre. Broccoli, cantaloupe and processing tomato were tolerant of SAN 582 at 0.94 lb/acre. Broccoli and carrot were tolerant of sulfentrazone at 0.15 lb/acre.

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Virender Kumar, Daniel C. Brainard, and Robin R. Bellinder

brown mustard, and oats can be planted in spring before short-duration, late-planted vegetable crops for weed management in vegetable cropping system. Brassica cover crops can suppress weeds ( Al-Khatib et al., 1997 ; Boydston and Al-Khatib, 1994

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David M. Butler, Gary E. Bates, and Sarah E. Eichler Inwood

; Orzolek, 1996 ). Although these systems can improve vegetable crop yields and quality, the system is also resource and capital-intensive, requiring substantial soil disturbance and tillage. Intensive tillage systems for continuous vegetable production can

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Carlos Campillo, M.I. García, C. Daza, and M.H. Prieto

, linear and/or mobile sensors. This study aimed to develop a cheap and simple method to estimate LAI based on measurements of PGC in two vegetable crops with notable differences in leaf type and plant architecture; it was based on analyzing digital