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Overhead pulse irrigation was evaluated as an alternative irrigation practice to reduce container leachate and irrigation runoff. Six irrigation treatments evaluated included 1.25 cm volume applied at 1, 2, and 3 pulses and 0.63 cm volume applied at 1, 2, and 3 pulses with a 1 hr delay between pulses. Irrigation runoff and container leachate were about 50% less in the 0.63 cm treatments compared to the 1.25 cm treatments. There was a 10-14% reduction in irrigation runoff and 29-32% reduction in container leachate when comparisons were made between the 1 pulse and 3 pulse treatments regardless of the irrigation volume applied. Shoot and root growth of Compacta holly were similar among all treatments.
Pampas grass seedlings in 72-cell pack containers were transplanted into containers with a root observation window (17.8 × 10.2 cm) and treated with selected preemergence applied herbicides. Root numbers were counted in the upper and lower 8.9 cm of the viewing window until 16 days after treatment (DAT) when the windows became full of roots. Root growth in both the upper and lower window was suppressed with application of Factor 65 WG and Pendulum 60 WDG at the X and 2X rates at 16 DAT. Ronstar 2G and Pendulum 2G at the recommended rates and nontreated control plants had similar root numbers at 16 DAT. At 16 DAT, the greatest number of club roots formed on plants treated with the dinitroaniline herbicides; Pendulum 2G, Pendulum 60 WDG, and Factor 65 WG. Shoot growth was not affected by treatment.
Blue color development in Hydrangea macrophylla is usually accomplished by applying Al as an alum drench. Drenches are applied during forcing 10–14 days after transplanting at a rate of 17,500 mg·L-1. Cultivars Blue Wave and Nikko Blue were used to evaluate if the Al contained in waste paper can provide the necessary Al for blue flower development. Two waste paper forms, pelletized and crumble, were used as surface mulches and as media amendments. The amendments were incorporated into the media at transplanting and mulches were applied either at transplanting or 28 days later. Alum drenching was initiated at transplanting as a control. Leachates were collected weekly using the VTEM. Total Al, electrical conductivity, and pH were determined on all samples. All waste paper treatments resulted in pink flowers in both cultivars. Leachate pH, from plants in this test, was >6.5. Aluminum concentration was greater than the 15 mg·L-1 Al needed for blue color development in flowers, but Al concentration decreased with time. Control of pH at the waste paper surface and in the media is critical for increasing the availability of labile Al for uptake by hydrangea.
Herbicide-blended and coated fertilizers were evaluated for prostrate spurge control in containers. Ronstar 2G or Pennant 5G was blended with Nursery Special 12-6-6 fertilizer and Ronstar 50WP or Pennant 7.8E was sprayed on the fertilizer (coated). Ronstar 2G-blended fertilizer and Ronstar. 50WP-coated fertilizer provided weed control at the 4, 8, and 16 lb ai/A rates similiar to broadcast (2G) or sprayed (50WP) herbicide applied at the label rate (4 lb ai/A). Ronstar provided better prostrate spurge weed control than Pennant. Formulation had no affect on weed control when comparing blended or coated fertilizer. Herbicide-blended and coated fertilizers provided effective prostrate spurge contol in containers.
Several experiments were conducted to determine release rates of five oxadiazon-coated fertilizers. Five fertilizers and 4-mm glass beads (nonabsorbent control) were coated with 14C-oxadiazon + formulated oxadiazon, then placed in a separatory funnel and leached with 20 ml of water for 14 days. 14C-oxadiazon was quantified by use of liquid scintillation spectrometry. For glass beads, Nutricote, Meister, and Osmocote, 70% to 80% of the 14C-oxadiazon was recovered in the first two leaching events. Oxadiazon leached from Polyon was 47% during the first two events and remaining oxadiazon was slowly released over the next 12 leaching events. 14C-oxadiazon from the other fertilizers over the last 12 days of leaching was less than that recovered from Polyon. Evaluation of the total surface area of a 50-g sample revealed Polyon had the greatest total surface area of the five fertilizers. Scanning electron micrographs before and after leachingindicated potential erosion of the Polyon surface compared to little or no change in the surfaces of the other fertilizers.