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(to collect leachate) at 6 d after transplanting and then fertigated daily with a Hoagland’s nutrient solution (mg·L −1 : 40 N, 1.5 P, 28 K, 4.3 Mg, 6.5 S, 10 Ca; µg·L −1 : 52 B, 52 Cu, 225 Fe, 100 Mn, 20 Mo, and 100 Zn; Hoagland and Arnon, 1950

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The presence of the growth regulators paclobutrazol and uniconazole in leachate or distribution through media consisting of various proportions of Douglas fir bark, sphagnum peat and perlite was evaluated. Distribution through a column 25 cm deep occurred rapidly and growth regulators were found in the leachate the first day after drench application when perlite was in the mix. Movement was limited to a maximum of the top 60% of the column in bark and peat mixes without perlite. Leachate was collected daily over a 12 day period after drenches were applied. Paclobutrazol and uniconazol showed similar distribution patterns in the media.

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wool. After each irrigation event, 2 mL of leachate from each lysimeter was transferred to a sealable 2-mL tube (Fisher Scientific) and then stored in a freezer at –10 °C. For all studies, care was taken to prevent contamination between samples and to

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between the means of the substrate static physical properties, particle size fractions based on dry mass, crop responses, foliar nutrition, leachate analysis, and microbial communities. In addition, standard error was calculated using JMP Pro (15.1.0) to

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Abstract

The report of Poole and Chase (1) continues a misconception that exists concerning the determination of potting soil salinity characteristics, namely, that potting soil conductivity can be determined from the leachate.

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Two studies were conducted to determine if selected grass and dicot species had an allelopathic interaction with pecan (Carya illinoinensis Wangenh. C. Koch). Leachate from pots with established grasses or dicots was used to irrigate container-grown pecan trees. Leachates from bermudagrass [Cynodon dactylon (L.) Pers.], tall fescue (Festuca arundinacea Shreb. cv. Kentucky 31), redroot pigweed (Amaranthus retroflexus L.), and cutleaf evening primrose (Oenothera laciniata Hill) reduced leaf area and leaf dry weight about 20% compared to the controls. Bermudagrass, tall fescue, and primrose leachate decreased pecan root weight 17%, trunk weight 22%, and total tree dry weight 19% compared to the control. In a second study, trees were 10% shorter than the control when irrigated with bermudagrass or pigweed leachate.

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Leachates were produced by washing Hydra-fill, a polyurethane ester foam, with water. These leachates decreased radish (Raphanus sativus L.) and tomato (Lycopersicon esculenturn Mill.) seed germination and were phytotoxic to seedlings. Washing the foam for as little as 5 minutes (compared to not washing) before collecting the leachate significantly decreased the mean seed germination time by 0.6 to 1 day. Rinsing the foam with ethanol before collecting the leachate was detrimental to germination. When used as a potting medium component, the foam reduced radish shoot and root dry weights compared to potting media without foam. Washing the foam with tap water before use resulted in increased radish shoot and root dry weights. Hydra-fill generally reduced plant performance when included in potting media. However, radish grew well in fresh 25% Hydra-fill (raw or washed) mixed with loam.

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Abstract

Suppressed growth and chlorotic leaves of Japanese holly (Ilex crenata, Thunb. ‘Hetzii’) when grown in hardwood bark, were caused by the uptake of excessive amounts of available Mn in bark leachates.

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Three commonly used nursery media were packed into 10×40 cm long PVC plastic columns. Two treatments of aqueous applied napropamide [2-(αnapthoxy)-N,N diethyl propionamide] were used including: 1) 13.44 kg/ha, 2) 20.16 kg/ha. Two water treatments were applied to the columns: 1) 2.54 cm/.405 ha, 2) 5.08 cm/.405 ha. Leachate from the columns was collected every three days for a period of two weeks. Quantitative bioassay testing using a napropamide sensitive plant species Hordeum vulgare L. (barley) have indicated a downward linear trend in the growth of roots and shoots when exposed to increasing concentrations of napropamide in controlled petri dish experiments. Preliminary leachate studies indicate that napropamide concentrations in the leachate collected are below levels detectable by the barley bioassay (< .25 ppm) at the label recommended rate of 6.72 kg/ha. Gas chromatography studies will be conducted to confirm napropamide concentrations in the collected leachate.

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Ebb- and-flow irrigation is an economically attractive subirrigation method that reduces labor costs and eliminates runoff from greenhouses. The effects of fertilizer concentration on growth of subirrigated pansy (Viola ×wittrockiana Gam.) and the leachate electrical conductivity (EC) and pH were quantified, using two growing media. Leachate EC increased as the EC of the fertilizer solution increased from 0.6 to 3.6 dS·m–1 (70 to 530 mg·L–1 N). The leachate EC was fairly constant over time when the EC of the fertilizer solution was 0.6 dS·m–1, while it increased throughout the experiment at higher fertilizer concentrations. MetroMix 300 leachate consistently had a higher EC than did MetroMix 500. Leachate pH of both growing media was similar throughout the growing season. The pH decreased over time and was lower with higher fertilizer concentrations. Optimal plant growth occurred with a fertilizer EC of 1.2 or 1.8 dS·m–1, and a leachate EC between 1.5 and 4 dS·m–1. Increasing the concentration of the fertilizer solution resulted in increased shoot tissue levels of P and Mn and decreased tissue levels of K, Mg, and Na. The results of this study indicate that pansy is not very sensitive to the EC of the growing medium and can be grown successfully in a closed subirrigation system.

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