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Brian A. Birrenkott, Joseph L. Craig, and George R. McVey

A leach collection unit (LCU) was assembled to capture all leachate draining from a nursery container. An injection molded 2.8-L nursery container was plastic welded into the lid of a 7.6-L black plastic collection bucket so that the bottom 2.5 cm of the nursery container protruded through the lid. The LCU was designed to track total N release from CRFs without confounding effects of plant uptake or N immobilization. Total N released between any two sampling periods is determined by multiplying the N concentration in a leachate subsample × total leachate volume. The LCU were placed in a container nursery area with overhead irrigation. LCU were thoroughly leached before sampling the leach solution. To study the effects of substrate on N leach rates, Osmocote 18.0N–2.6P–9.9K (8 to 9 months 21 °C) was incorporated at 1.8 kg N/m3 using a locally available, bark-based substrate or medium-grade quartz sand. The experiment was conducted at Scotts Research locations in Apopka, Fla., and Marysville, Ohio. Osmocote incorporated into either a bark-based substrate or sand resulted in similar N release profiles. Although substrate did not affect N leach rate, quartz sand was recommended as the substrate in the leach collection system for polymer-coated CRFs. Quartz sand is chemically and biologically inert, does not immobilize nutrients and has low ion exchange capacity compared to bark-based potting substrates. More than 90% of the total nitrogen applied from Osmocote was recovered from leachate and unreleased N in fertilizer granules. This research has demonstrated the leach collection system as a reliable means to quantify nitrogen release rate of a polymer-coated CRF under nursery conditions. The LCU, when used with a crop plant, allows nutrient budget and nutrient uptake efficiency to be determined for CRFs.

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Borut Gosar and Dea Baričevič

PE mulch), and uncovered ridges (control). Split plots, each with a length of 30 m, consisted of three different RFRRH sub-plots. Each sub-plot measured 14 m 2 and consisted of two rows (ridges) with a length of 10 m. In the RFRRH system with mulches

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Bert M. Cregg, Pascal Nzokou, and Ron Goldy

. Table 1. Weed control, irrigation, and bedding production systems for Christmas tree mulch study at MSU Southwest Michigan Research and Extension Center, Benton Harbor, MI. After site preparation, polyethylene mulch, bedding, and irrigation were

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Abby ShalekBriski, B. Wade Brorsen, Jon T. Biermacher, Charles T. Rohla, and Will Chaney

young pecan trees in Georgia. Wells compared two microsprinkler systems with emitters of different pressures and a nonirrigated control. During the first 2 years of the experiment, irrigated trees had greater trunk diameter growth than the nonirrigated

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Chung-Liang Chang and Ming-Fong Sie

evolution analysis. However, to integrate and design a control system with a crop growth model can be difficult as a result of diversity of plant growth factors, comprising internal, external (environmental factors), and biological factors. Internal factors

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Christian A. Wyenandt, Landon H. Rhodes, Richard M. Riedel, and Mark A. Bennett

be as high as 100%. Because of the threat of diseases such as septoria leaf spot, fungicides are applied to nearly 100% of the processing tomato crops grown in the Midwest ( Precheur et al., 1992 ). If necessary, tomato growers control septoria leaf

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Pascal Nzokou, Nicholas J. Gooch, and Bert M. Cregg

( Young and Sisson, 2002 ). Using an automated irrigation system controlled by three different soil tension thresholds resulted in more efficient water use, reductions in pollution runoff, and increase in growth of ‘Kardinal’ rose ( Rosa × hybrida

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Marco Fontanelli, Luisa Martelloni, Michele Raffaelli, Christian Frasconi, Marco Ginanni, and Andrea Peruzzi

been imported from the United States and operate from the sides of the crop row and beneath the crop leaves ( van der Weide et al., 2008 ). In addition, advanced technology machines for physical weed control, which use a precision vision guidance system

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Tiziano Caruso, Francesco Guarino, Riccardo Lo Bianco, and Francesco Paolo Marra

, because of the presence of low secondary branches, Y trees were soil worked and irrigation lines were raised to ≈30 cm. Integrated pest control was performed using low-volume sprayers at 1 or 1.5 m 3 ·ha −1 per year for MSB or Y system, respectively

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Martin P.N. Gent and Michael R. Short

this scenario. A system in which the excess solution drained from the plants was recycled through a secondary watering system each week was compared with a control in which only fresh nutrient solution was supplied to the plants. Otherwise the watering