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H.J. Jia, K. Mizuguchi, K. Hirano, and G. Okamoto

Effects of fertilizer application levels on fruit texture and flesh pectin compositions of a melting peach were investigated. Hakuho trees (Prunus persica Batsch) were supplied with normal (M), high (H; M × 2), and superhigh (SH; M × 4) levels of complete liquid fertilizer twice a week. Flesh firmness of the H and SH treatment fruit was lower than that of M treatment fruit at the hard-mature and firm-mature stages, although no difference was detected at the full ripe stage. Sensory scores for flesh texture at the full ripe stage were highest in the N treatment fruit and lowest in the SH treatment fruit. The content of water-soluble polyuronides (WSP) in flesh was highest in SH fruit and lowest in M fruit at the hard-mature stage, although the difference became smaller at the full ripe stage. Molecular mass analysis using a gel filtration column revealed that water-soluble polysaccharides in alcohol-insoluble solids (AIS) of the H and SH fruits had a peak of high molecular mass, ≈200 kDa, at the hard-mature stage, and the molecular mass decreased gradually to ≈23 kDa at the full ripe stage. In the M fruit, however, the molecular mass was rather constant during the ripening period, 112 kDa even at the full ripe stage. The analysis of acidic fractions (pectin) in the polysaccharides using an ion exchange column, as well as juice gellation test by adding Ca and Tris buffer, also indicated that high levels of fertilizer application impairs an early degradation of flesh polyuronides resulting in the accumulation of low-molecular-weight WSP. This may ultimately cause the inferior flesh texture of overfertilized peach fruit.

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Amit Bhasin, Joan Davenport, Scott Lukas, Qianwen Lu, Gwen Hoheisel, and Lisa W. DeVetter

a period of high N demand to support the current season growth. Therefore, ensuring that N is available for plant uptake from bloom through harvest is recommended. Nitrogen fertilizer applications during or after harvest are currently not advised

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R.L. Parish, R.P. Bracy, and H.F. Morris Jr.

A study was conducted to evaluate the effect of banding or broadcasting fertilizer on yield and quality of turnip (Brassica rapa L. Rapifera group), sweetcorn (Zea mays var. rugosa Bonaf.), and cabbage (Brassica oleracea L. Capitata group). Preplant fertilizer was applied broadcast before bedding, broadcast after bedding, or banded after bedding. Sidedress applications were broadcast or banded on the beds. Differences in plant size and vigor were noticed early in the season in the spring turnip crop, with the growth in the broadcast-and-bed treatment appearing superior. The yield at first harvest and total yield were lower for turnip grown with the bed-and-broadcast treatment. No differences in yield of cabbage or sweetcorn resulted from the treatments. Few differences in turnip stem-to-leaf ratio were noted due to fertilizer treatment. Few differences in yield due to sidedress method were noted with any of the crops. Analysis of soil samples in a grid pattern across the beds showed that the location of the fertilizer after the broadcast-and-bed treatment was similar to the placement of the banded fertilizer. Since broadcasting can be done with a faster, wider applicator, growers could reduce costs by broadcasting fertilizer and obtain yields that are at least equivalent to the yields obtained by banding the fertilizer.

Open access

Yuqing Wang, Richard J. Heerema, James L. Walworth, Barry Dungan, Dawn VanLeeuwen, and F. Omar Holguin

applied Zn EDTA can eliminate Zn deficiency symptoms, orchards managed exclusively by soil Zn fertilizer application usually have lower leaf tissue Zn concentrations than comparable orchards managed with foliar Zn sprays, and it therefore has recently been

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Martin M. Maboko and Christian P. Du Plooy

very efficient method of plant nutrition during the intensive growth stages ( Giskin et al., 1984 ; Komosa, 1990 ; Mengel, 2002 ). Foliar fertilizer application is a technique using foliar sprays to provide the nutrients at the actual site of activity

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Martin M. Maboko, Christian Phillipus Du Plooy, and Silence Chiloane

supplement, foliar fertilizer application is gaining popularity among growers as a standard practice in agricultural crop production because it is more purposeful and environmentally friendly as opposed to soil fertilization ( Maboko and Du Plooy, 2017

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Julie Fulenwider* and David Creech

General guidelines for the fertilization of azaleas in Southern landscapes often suggest applications be made after bloom. Early fertilizations are thought to encourage earlier blooms which are more likely to be damaged by spring freezes. Three years of data will be presented. Treatments include four fertilization rates, and various times of application from early (December-January) to late (March-April). Four to six varieties were evaluated (depending on the year of the study) in the SFA Ruby M. Mize Azalea Garden and in plantings on the Stephen F. Austin State Univ. campus. A randomized complete block design was utilized with three plants per replication. Influence of timing and rate of fertilizer application on bloom date and persistence. Influence of fertilizer treatments on leaf nutrient concentrations will be presented.

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R.A. Sink, A.E. Einert, G.L. Klingaman, and R.W. McNew

Use of groundcovers in the landscape is often limited due to their slow establishment rate compared to that of turf. Hedera helix L., (English ivy), Euonymus fortunei `Coloratus' (Turcz.) Hand.-Mazz. (purpleleaf wintercreeper euonymus), and Liriope spicata Lour. (creeping lily-turf) were evaluated in a full sun and 50% shade environment to determine the effects of fertilizer applications on their establishment and growth. Fertilizer treatments, of 13N-13P-13K at a rate of.45 kg/93 m2, used were: 1) at planting only; 2) at planting and once during the summer; 3) at planting, in summer, and once in the fall; or 4) at planting, in summer, in fall, and once the following spring. Data collected included fresh and dry weight comparisons of pruned material, percentage canopy cover, plant quality and vigor by visual assessment and photographs, and time required for maintenance of each plot. Results show limited fertilizer effects and interaction according to species during the first several months of growth. Establishment and survivability of Hedera was influenced mainly by light exposure rather than fertilizer applications. There was no difference in establishment rates between Liriope and Euonymus, however, under shade, Euonymus did not develop its characteristic fall color. Hedera was established in one season under 50% shade and can be considered very competitive with turf under the same conditions.

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Alison A. Stoven, Hannah M. Mathers, and Daniel K. Struve

The mineral nutrition requirements and fertilizer application methods for container-grown shade tree whips are not well understood. This experiment was conducted to determine the effects of fertility method (water soluble vs. controlled release) on growth, water, and N use efficiency of four taxa [(Acer ×freemanii `Jeffersred' (Autumn Blaze® maple), Cercis canadensis L. (Eastern redbud), Malus (Mill.), `Prairifire' (Prairifire crabapple), and Quercus rubra L. (red oak)] in two production environments [outdoor gravel pad vs. a retractable roof structure (RRS)]. No single fertilizer method consistently resulted in the greatest growth. In the RRS, maple and crabapple heights, and crabapple and redbud caliper were larger when whips were fertilized with controlled-release fertilizer (CRF); outdoors, CRF resulted in taller maples and larger caliper crabapples. However, in the RRS, maple whips fertilized with water-soluble fertilizer had higher production water use efficiency than those fertilized with CRF, whereas crabapple whips had higher N use efficiency when fertilized with CRF. Nitrogen use efficiency was higher for redbud and crabapple whips fertilized with CRF than with CRF. Outside, crabapple whips fertilized with CRF had higher production water use efficiency than those fertilized with water-soluble fertilizer. There were no differences in N use efficiency attributed to fertilizer method. When averaged over fertilizer application methods, height, caliper, water, and N use efficiency were greater when whips were grown in RRS than outdoors. There were two exceptions: Maple caliper and production water use efficiency were marginally higher when whips were grown outdoors. The greater growth for whips produced in the RRS was attributed to reduced ambient and substrate temperature stress.

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H.H. Krusekopf, J.P. Mitchell, T.K. Hartz, D.M. May, E.M. Miyao, and M.D. Cahn

Overuse of chemical N fertilizers has been linked to nitrate contamination of both surface and ground water. Excessive fertilizer use is also an economic loss to the farmer. Typical N application rates for processing tomato production in California's Central Valley are 150-250 kg·ha-1, and growers generally fail to fully consider the field-specific effects of residual soil NO3-N concentration, or N mineralization potential of the soil. The purpose of this research was to determine the effects of sidedress N fertilizer application, residual soil NO3-N, and in-season N mineralization, on processing tomato yield. Research was conducted during the 1998 and 1999 growing seasons at 16 field sites. Pre-sidedress soil nitrate concentration was determined at each trial site to a depth of 1 m, and aerobic incubation tests were conducted on these soils (top 0.3 m depth) to estimate N mineralization rate. Sidedress fertilizer was applied at six incremental rates from 0 to 280 kg N/ha, with six replications of each treatment per field. Only five fields showed yield response to fertilizer application; yield response to fertilizer was associated with lower pre-sidedress soil nitrate levels. In most fields with fertilizer response, yield was not increased with sidedress N application above 56 kg·ha-1. Mineralization was estimated to contribute an average of ≈60 kg N/ha between sidedressing and harvest. These results suggest that N fertilizer inputs could be reduced substantially below current industry norms without lowering yields, especially in fields with higher residual soil nitrate levels.