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Total salable yields of `Vendor' greenhouse tomatoes produced with 4 non-circulating, hydroponic methods were not significantly different from yields produced with conventional soil bed culture (5.69 kg/plant).
Three methods employed a capillary, sub-irrigated system wherein the plant container rested in a shallow, covered, polyethylene-lined tank containing 5 cm of nutrient solution. Plant containers consisted of 7 and 25 liter plastic pots containing a 1 hapuu:2 cinder medium plus 1 and 2 plants, respectively, and rockwool blocks (7.5 × 7.5 × 6.5 cm) resting on larger rockwool blocks (15 × 15 × 7.5 cm).
The fourth method consisted of rockwool blocks (7.5 × 7.5 × 6.5 cm) resting on a screen placed in a covered, 20 cm deep, polyethylene-lined tank filled with nutrient solution.
Abstract
Activated carbon applied in a 5 cm wide band over seeded rows of lettuce (Lactuca sativa L.) protected the lettuce from the injurious effects of several herbicide combinations. Although activated carbon rates greater than 0.38 g/linear m protected lettuce, a marginally tolerant crop, an increase in the rate of the activated carbon also decreased weed control within the treated band. For conditions in two reported Hawaiian locations, an activated carbon rate of 0.38-0.76g/linear m assured protection from herbicide damage with minimal weed growth in the treated band.
Abstract
Root dips of tomato transplants in slurries of activated carbon provided significant but not total protection from a 1 lb./A simulated residue of atrazine in the soil. Although activated carbon slurries did not damage roots, direct contact with the foliage caused severe injury.
Abstract
‘Great Lakes R-200’ (Lactuca sativa L.). seedlings were fertilized with preplant-incorporated 8N-14P-7K at 0-32 g/liter of medium and combined with daily misting of 13N-11P-21K at 0-1800 ppm using 6 different media. The recommended foliar range is 200—600 ppm combined with preplant incorporation of 0—8 g/liter of medium. The 200 ppm foliar treatment required 4—8 g/liter of medium-incorporated fertilizer while the 600 ppm foliar treatment required 0—4 g/liter. The 0 foliar treatment decreased seedling weight, head firmness, and head weight. The 1800 ppm foliar rate is undesirable since it can decrease head size and percent salable heads, and cause soft seedlings. Large differences among treatments at the seedling stage moderated at hearvest time. The highest preplant rates (16—32 g 8N-14P-7K/liter of media) caused excess salinity and this resulted in delayed seed germination and reduced seedling fresh weight. Total salable weight and average head weight were not influenced by any of the 6 media tested. However, a lower seedling fresh weight occurred with 1 medium in the first experiment and 2 media in the second experiment.
Abstract
Transitory yellowing, a new disease of Chinese cabbage (Brassica campestris L. ssp pekinensis Rupr.), was noticed in 1971 in the Lalamilo area on the Island of Hawaii. The disease was not associated with pathogenic microorganisms. The susceptibility varies with cultivar but no cultivar proved to be resistant. In the disease-free Volcano area no symptoms developed on plants growing in soil collected from the diseased area at Lalamilo. Application of a complete fertilizer or pH adjustment of soil did not alleviate the disease symptoms. Disease symptoms disappeared within 3 days when plants were transported from a diseased area to a healthy area. Results suggest that the new disease is caused by an unknown airborne agent present in the diseased area.
Abstract
When soil-water tension in the rootzone was maintained below 0.2 bar the yield of marketable ‘Tropic’ tomato was 17% greater than when tension was maintained below 0.4 or 0.6 bar. At all 3 tensions yields and total amounts of irrigation water required under trickle irrigation did not differ significantly from yields and water required under basin irrigation. Soil salinity tended to increase with decreases in the total amount of irrigation water applied and with distance from the center of the row. These tendencies were slight under basin irrigation but marked with trickle irrigation. The salt tolerance of ‘Tropic’ appears to be lower than that reported for other cultivars; tolerance was considerably lower on highly acid soil (pH 4.1) than on limed soil (pH 5.7). With limed soil the electrical conductivities of the soil water at field capacity associated with yield decreases of 10, 25 and 50% were 3.5, 6.8 and 12.2 mmho/cm, respectively, as compared to corresponding U.S. Salinity Laboratory values of 8.0, 13.4 and 16.0 mmho/cm.
Abstract
There is much current interest in improving materials handling in commercial green-houses. Two areas of concern are reducing labor costs and maximizing bench growing areas. Transport of materials is labor intensive in the conventional bench-and-aisle greenhouse, and the loss of bench growing area to walkways is costly and inefficient.
Abstract
A uniform and convenient herbicide application technique was developed for home vegetable gardens. 4-(Methylsulfonyl)-2,6-dinitro-N,N-dipropylanaline (nitralin) was either sprayed on the soil surface, or applied to 1 m wide sheets of water soluble plastic. A light sprinkling of water released the nitralin from the water soluble plastic and permitted soil adsorption. Weed control was excellent when 3.4 kg/ha nitralin was applied to the soil with water soluble plastic. Germinating vegetable seeds were protected from nitralin injury with a mixture of activated carbon and vermiculite. The “no-cultivation concept” may have broad horticultural application, especially in home gardens where herbicides are difficult to use.
Abstract
Head weights of ‘Nagaoka 55’ Chinese cabbage (Brassica rapa L. ssp. pekinenis (Lour.) Olsson) were 76–79% greater at a plant spacing of 43 cm than at 28 cm. Percentage salable and grade 1 heads both increased with increasing distance between plants. Seedlings were raised in cylindrical containers of 2.5, 3.75, 5 and 7.5 cm diameter × 6.4 cm depth for 3,4,5 and 6 weeks in a seedling house. Transplant age affected maturity time minimally and did not affect yield. Seedling fresh weight was greater in 7.5 cm containers than in the smaller containers at all transplant ages. Plants started in 7.5 cm containers matured 7.5 days earlier, produced 10% heavier heads and yielded 25–31% more than plants started in 2.5 cm containers. Plants from the larger containers probably performed better as a result of the more favorable physical properties or fertilization regime of the container media. The highest yields in these trials exceeded 3 MT/ha · day.