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Theoharis Ouzounis and Gregory A. Lang

cherry, meaning a greater proportion of fruit development occurs during active current-season carbon and N uptake. Foliar applications of urea in fall have had positive effects in deciduous fruit trees (e.g., Titus and Kang, 1982 ). Urea is the most

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Adam D. Karl, Michael G. Brown, Sihui Ma, Ann Sandbrook, Amanda C. Stewart, Lailiang Cheng, Anna Katharine Mansfield, and Gregory M. Peck

been found to be effective means of increasing grape YAN concentrations. For example, Moss (2016) found a cumulative application of 30 kg·ha −1 of nitrogen applied as urea to foliage was capable of more than doubling the YAN concentration in

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Moritz Knoche, Peter D. Petracek, Martin J. Bukovac, and Warren E. Shafer

14C-urea penetration of isolated tomato (Lycopersicon esculentum Mill. cv. `Pik Red') fruit cuticular membranes (CM) was studied as a function of concentration and temperature. There was no significant effect of cuticular wax on urea penetration at 25C, permeances for the CM being 8.4 × 10-10 and dewaxed CM (DCM) 11.1 × 10-10·m·s-1. Time lags were near zero for both CM and DCM. Steady-state diffusion analysis suggests that the relatively low cuticular permeance of urea is due to low partitioning that offsets high diffusivity. Urea flux through the CM and DCM showed ≈1.5- and 1.9-fold increases, respectively, for each 10C increase between 5 and 45C. Urea flux across CM and DCM increased linearly with concentration (10 μm to 1 m) and, thus, was a first-order process.

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Guoqiang Wang, Ping Qu, Hongying Huang, Guofeng Wu, and Haijun Yan

in the growth medium can act synergistically to promote seedling root development ( Balestri et al., 2015 ; Gonzálezfernández et al., 2015 ; Mininni et al., 2015 ; Ravindran et al., 2016 ). Urea formaldehyde resin is a low-cost polymeric

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Melissa L. Wilson, Carl J. Rosen, and John F. Moncrief

Controlled-release fertilizers are being used more frequently for crop production in an effort to improve plant nitrogen (N) use efficiency and reduce nitrate leaching. Polymer-coated urea (PCU) is a controlled-release fertilizer that releases N

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Lijuan Xie, Deying Li, Wenjuan Fang, and Kirk Howatt

‘Penncross’ creeping bentgrass in May 2005. The grass was mowed weekly at 2.19 inches height. Nitrogen (N) was applied at an annual rate of 2 lb/1000 ft 2 from polymer-coated sulfur-coated urea (43N–0P–0K, NS-54; The Andersons, Maumee, OH) in two equal

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Oscar L. Vargas and David R. Bryla

, the most common N fertilizers applied to blueberry are ammonium sulfate and urea. Both are excellent sources of ammonium-N but the latter requires soil temperatures greater than 20 °C for complete breakdown and is only half as acidifying as ammonium

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Yin-Tung Wang and Yao-Chien Alex Chang

15K–2.2P–12.5K (N = 78% nitrate + 8% ammonium + 14% urea), as N concentration increased from 0 to 200 mg·L −1 , leaf span, leaf number, total leaf length, and flower count all increased ( Wang, 2010 ) ( Fig. 1 ). In this study, the increase in flower

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S. Laywisadkul, C.F. Scagel, L.H. Fuchigami, and R.G. Linderman

decreases the amount of N mobilized from leaves to stems and roots in the autumn; thus, it can reduce N reserves required for growth the following spring ( Bi et al., 2003 ; Guak et al., 2001 ). The combination of foliar sprays with urea and CuEDTA can be

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A.M. Akl, Faissal F. Ahmed, Farag M. El-Morsy, and Mohamed A. Ragab

The effect of single or combined application of urea-formaldehyde at 80 g N/vine, sulfur at 0.4%, and three compounds of iron (chelated, sequestered, and sulfate forms as 0.1%) on productivity of `Red Roomy' grapevines was studied during 1995 and 1996. A substantial increase in berry set, number of clusters, yield weight of clusters and berries, total soluble solid sugars, and anthocyanins was observed because of the application of these fertilizers singly or in combination. Total acidity in the juice was reduced because of application of these fertilizers. Combined application of urea-formaldehyde, sulfur, and chelated iron gave the best results with regard to yield and quality of berries. An economical yield was obtained on `Red Roomy' vines supplied with urea-formaldehyde at 80 g/vine, sulfur at 0.4%, and chelated iron at 0.1%.