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Non-target herbicide losses pose environmental concerns for nurseries. Therefore, the objective of this research was to determine the ability of each alternative mulch to suppress weed growth when compared to traditional chemical methods. Uniform quart liners of Lagersroemia indica × faurei `Natchez' were planted in 15-gal containers 15 June 1999, on a gravel container pad using overhead irrigation. Weed pressure was uniform. Treatments include Regal 0-0 3 G (3 lb ai/a) as a broadcast or individual container application, recycled newspaper pellets (1 inch thick), Spin-out coated recycled newspaper pellets (1 inch thick) geotextile disks (Spin-out coated), kenaf mulch, waste tire crumbles, wheat straw (2 inches thick), oat straw (2 inches thick), cereal rye straw (2 inches thick), paper mill sludge (2 inches thick), a handweeded control, and a weedy control. Treatments were organized in a RCBD consisting of eight single-plant replicates. The geotextile disks, newspaper pellets treated with spin-out, and shredded rubber tire treatments all had better than 80% weed control from 30 to 180 DAT. These alternative weed control methods can provide a good alternative to conventional weed control practices in large container-grown ornamental.
Turfgrass is grown under extremely variable light intensities. This presents difficult management problems, and methods are needed to improve turf performance under variable shade conditions. Two experiments were conducted to determine the influence of trinexapac-ethyl (TE) on turf performance and physiological responses of `Diamond' zoysiagrass [Zoysia matrella (L.) Merr.] under several light intensities. In a polyethylene-roofed greenhouse, `Diamond' was sodded in 12 wooden boxes (1.2 × 1.2 × 0.16 m) (Expt. 1) and 18 fiber containers (55 × 38 × 12 cm) (Expt. 2). Treatments applied to boxes or containers included three levels of shade (40%, 75%, and 88%) with and without multiple TE applications at 48 g·ha-1 of active ingredient. Without TE treatment, vertical shoot growth increased linearly with increasing shade levels. Excessive shoot growth under 75% and 88% shade exacerbated energy depletion, as evidenced by the 45% and 67% lower rhizome mass and the 37% and 65% lower total nonstructural carbohydrate content (TNC), respectively, compared with turf under 40% shade. Trinexapac-ethyl reduced excessive vertical shoot growth and increased rhizome mass and TNC. Mean turf quality was increased by 0.7 and 1.4 units for turf receiving multiple TE applications under 75% and 88% shade, respectively. Trinexapac-ethyl did not increase turf quality or TNC under 40% shade. Canopy photosynthetic rate (Pn) was not affected 4 weeks after the initial TE treatment under any shade level. However, 34 weeks after the initial TE treatment a 50% higher Pn was observed for turf treated with TE under 88% shade, possibly because of higher tiller density. Repeated TE application increased turf quality and provided more favorable physiological responses (such as TNC and Pn) under 75% and 88% shade, where conditions favored vertical shoot growth. However, little or no improvement in turf quality was observed under 40% shade, where conditions favored slow vertical shoot growth. Chemical name used: 4-(cyclopropyl-α-hydroxy-methylene)-3,5-dioxo-cyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl).
Abstract
Tomato (Lycopericon esculentum Mill.) and cabbage (Brassica oleracea L. Capitata group) transplants were grown in peat-vermiculite (P-V) or in media containing sewage sludge compost from either a residential, low metal (LM) or industrially contaminated, high metal (HM) source. The transplant quality (stem diameter, fresh, and dry weight) of plants grown in P-V and LM were similar. Transplants grown in HM media were small, less-developed, and exhibited symptoms of heavy metal phytotoxicity. The concentrations of Zn, Fe, Mn, Cu, Pb, Cd, and Ni in tomato and of Zn, Cu, Cd, and Ni in cabbage plants grown in HM media were significantly higher than those in transplants grown in LM media. The addition of peatmoss to LM media had little influence on media pH or the heavy metal concentrations in transplants. However, peatmoss lowered the pH of HM media and thus the concentrations of Zn, Mn, Cu, and Ni in tomato and Zn and Mn in cabbage transplants increased. Concentrations of Zn and Cu in tomatoes and Zn in cabbage were above phytotoxic levels.
Abstract
Transplant quality, as measured by height and dry weight, of cabbage (Brassica oleracea L. Capitata group) and tomato (Lycopersicon esculentum Mill.) was lower for plants grown in media containing sewage sludge compost with a high heavy-metal concentration (HM) than for plants grown in peat-vermiculite (P-V) or low-metal (LM) sewage sludge compost media. Compost source had no significant effect on transplant quality of muskmelon (Cucumis melo L.) seedlings. Marketable yield of cabbage, tomato, or muskmelon was similar regardless of the media used to grow the transplants. The concentration of Zn, Cu, Mn, Ni, and Cd were significantly higher in transplants grown in HM media than in those grown in LM media. With the exception of Cd, metal levels in transplants grown in LM media were similar to those grown in P-V. Transplant media had little influence on the heavy-metal concentrations found in either foliar samples or the edible portions of the crops studied. Heavy-metal concentrations in foliar samples of all 3 crops were lower than those found in transplants. The lowest concentrations were found in tomato and muskmelon fruit, and in cabbage heads. The Cd concentrations in edible portions were very low regardless of the source of compost in the transplant media, indicating that sewage sludge composts, particularly those low in heavy metals, can be used safely in the growing media of vegetable transplants.
Descriptive analysis was used to compare sensory color, flavor, and textural attributes of Georgia-grown carrots. The relation between °Brix, total sugar, and intensity perception of sweetness was also studied. Significant differences existed in the perception of sweet taste and of color, and in levels of °Brix and percentage of sugar among all cultivars, but perceived intensity of sweetness was not related to the levels of °Brix or percentage of sugar. No significant differences were found among cultivars in harsh carroty, green, astringent, and earthy flavors, and in the perception of sour taste. Intensity ratings for perceived hardness were nonsignificant in either study. Differences in sensory profiles existed among all cultivars, but no trend was evident in the relation of sweetness to harsh flavor.