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Critiqued by: Brandy Marshall

Health Sciences – Biology Department

Tennessee Technological University

Cookeville, TN 38505



Title of Scientific Article:

Effects of nitrate-, ammonium-, and organic-nitrogen-based fertilizers on growth and yield of tomatoes



Heeb, Anuschka, Bengt Lundegardh, Tom Ericsson, Geoffrey P. Savage



The Journal of Plant Nutrition and Soil Sciences. Volume 168:Pages 123-129



This article covers an experiment involving the effect different nitrogen fertilizers on tomato plants. The objective of the study was to “compare the effect of different N forms and rates on yield and fruit quality of tomato plants in a controlled greenhouse environment.” To do this they applied different amounts of NH4+ to plants and compared them with plants with NO3- as their dominant source. By the end of the experiment, the objective had been reached.




a)      The article is consistent.

b)      The title of this article describes exactly what the paper is about.

c)      The literature cited in the introduction does effectively lead you to the objective statement.

d)      There are 16 citations in the introduction. Most of them support the objective statement, however a few do not.

e)      Yes, the objective statement is thorough and specific.

f)        The methods and materials section is logically arranged, but is not supported by any literature references.

g)      Yes, the experiment could be repeated by following the procedures in the Methods and Materials section.

h)      Yes, the results are arranged similar to the Methods and Materials.

i)        The results are presented in a fairly simple way, although a little hard to follow.

j)        Yes, the graphics are clear and are necessary.

k)      Yes, the discussion section really does discuss the results.

l)        Yes, the literature cited in the discussion includes those used to build the arguments in the introduction.

m)    The references cited in the discussion do support the results.

n)      The objective of this experiment was met.

o)      Most of the Journals cited in the literature cited were acceptable peer reviewed articles, however many of them could be considered out of date.



The paper was well written and the objective was met.



Even though it was well written, one has to pay very close attention to the different types of nitrogen and what is being done with each type to not get confused.



This study could be very beneficial to tomato farmers when they are trying to decide if the money they are spending on fertilizers really helps them in the long run.


Additional research

The article introduced a few plant conditions that were not fully explained, such as blossom-end-root and ammonium toxicity that one might want to research in more depth.