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  • Author or Editor: J. Benton Jones Jr. x
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Abstract

At the 1987 International Conference on Heavy Metals in the Environment, conferees expressed concern regarding the accuracy of analytical data in the published scientific literature. Journals dealing with human health and environmental issues are now rejecting papers in which authors fail to use either accepted reference methods of analysis and/or do not include assay results for a recognized standard as a means of verification of accuracy for their reported analytical results.

Open Access

Abstract

In the Feb. 1987 issue of HortScience 22:34-36, I was interested in the paper by Charles A. Mullins entitled “Effects of Nitrogen Fertilization on Production of Mechanically Harvested Snap Beans”. However, I found that two very important items of significance were not given:

  1. The form of N applied was not given. It would be assumed that the N fertilizer was applied at seeding, although this was not specifically indicated. The form of N can have a marked effect on the response of snap bean to applied N.

  2. Soil-testing information was given, but no identification of the method of extraction. Therefore, the values reported are meaningless without knowing how the test result was obtained. Such details are significant if the reader is to use the findings reported.

Open Access

Easter Lilies (Lilium Longiflorium) were grown in potting media containing 50% peatmoss and 50% vermiculite V/V or amended with 25, 33, or 50% (V/V) composted municipal sludge.

Macro and micro nutrient levels were determined for the various media formulations using either a water or a Mehlich III extraction procedure. Foliar levels of micro and macro nutrients were determined at anthesis. Final plant height and number of buds per plant were measured for each treatment.

No media formulations were phytotoxic; however, several micro element levels increased with increasing composted sludge content in foliar samples. These increasing foliar levels of Cu, Fe, Zn correlated well with media levels when Mehlich III was the extraction method. A similar correlation was not found with water as the extractant.

Free access

Abstract

The establishment of an average elemental composition for snap bean to satisfy nutritional labelling requirements is probably not possible. Analysis for the elemental content of 40 frozen snap bean samples collected at 8 locations in the United States revealed a wide range in concentration for the 18 elements determined. Several causes for this wide variation are suggested.

Open Access

Abstract

Soils, and leaf and fruit tissues were collected from 200 peach orchard sites during the 1970 growing season. Results obtained were not markedly different from those obtained in an earlier survey in 1962. Most of the soils were quite acid and the peach leaf N levels were below optimum. Most growers appeared to be overfertilizing with P but applying adequate K. Peach fruit were quite high in K, accounting for a sizeable removal of K from the soil.

Open Access

Abstract

Tomato (Lycopersicon esculentum Mill. ‘Floradel’) plants were grown under greenhouse conditions in a modified Hoagland’s solution to determine the influence of NO3:NH4 ratio (100:0, 75:25, 50:50, 25:75) on vegetative growth, fruit development, and tissue levels of N, P, K, Ca, and Mg at 3 stages of maturity. Vegetative growth prior to fruit set was increased significantly by adding 25% of the N as NH4, although higher NH4 ratios reduced vegetative growth. During flower and fruit development, the number of fruit formed with each flower cluster was not influenced by the NO3:NO4 ratio, although fruit weights were reduced significantly when NH4 supplied any part of the N form. With each increment of NH4 in the N ratio, tissue P increased whereas K, Ca, and Mg decreased. Kjeldahl N (less NO3-N) in the vegetative tissue at all harvests increased with each increment of NH4 in the N ratio. It is concluded that the use of Kjeldahl N as an indicator of the N status of the plant without consideration of the effect of N form on the percentage of N as well as the uptake and distribution of other essential elements could be misleading and potentially a misuse of this diagnostic tool.

Open Access

Abstract

A shift in the form of Ν in the nutrient solution to all NH4 after initial bloom significantly reduced pod yield as much as 50%, depending on the prebloom NO3/NH4 ratio. Pod yield was unaffected by prebloom NO3/NH4 ratio if at least half of the Ν in the nutrient solution was NO3, or if NO3 supplied all of the Ν during postbloom development. Therefore, for maximum pod yield, NO3 should be the primary Ν form supplied to snapbean plants after bloom. Kjeldahl Ν values were consistently high in the vegetative tissue with NH4 as the predominant Ν form, indicating that the use of Kjeldahl Ν values as an indicator of the Ν status of the plant in relationship to pod yield would be a misuse of this diagnostic tool without knowing the predominant Ν form being absorbed by the plant. The NO3 content in upper mature leaves at pod maturity was significantly correlated (r = 0.88***) to NO3 level applied, with a value of 7000 ppm in the leaves associated with highest pod yield. Total Ν (Kjeldahl Ν + NO3) of at least 5.50% in upper mature leaves at pod maturity was associated with highest pod yield.

Open Access