Paper · 2012 · Iowa State University Digital Repository (Iowa State University)

Sulfur fertilization response in Iowa corn and soybean production

John E. Sawyer; Brian J. Lang; Daniel W. Barker

2
claims
3
verbatim quotes
7
citations
2
research areas
✓
Open access

Abstract

Sulfur (S) is often classified as a “secondary” plant essential element, mainly due to a smaller plant requirement but also because it is less frequently applied as a fertilizer compared to other nutrients like the “macronutrients” nitrogen (N), phosphorus (P), and potassium (K). This has certainly been the case in Iowa where research for many years had not documented S deficiency or fertilization need for optimal corn or soybean production. However, if deficient, S can have a dramatic effect on plant growth and crop productivity – more than the classification “secondary” would imply. In Iowa, before 2005 more than forty years of field research with corn and soybean conducted at many locations across the state had measured a yield response to S fertilizer application only three times out of approximately 200 trials – an indication of adequate available S supply and limited deficiency. This began to change in the early 2000’s as producers in northeast Iowa noticed yellow plant foliage and reduced growth in areas of alfalfa fields. After investigating several potential reasons for the growth problems, such as plant diseases, research in multiple fields documented improved alfalfa plant coloration, growth, and forage yield with S fertilizer application (Lang et al., 2006). These responses, as well as questions about deficiency symptoms in corn, led to investigation of potential response to S application in corn and soybean.

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Claims 2

Observationobservedoriginal resultmeasured

Claim · model-written summary

Before 2005, sulfur fertilizer increased yield in only three of about 200 Iowa corn and soybean trials.

Treatment
S fertilizer applicatione0
Outcome
yield responsee0
Value
three times out of approximately 200 trialse0
Setting
Iowat0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Glycine max
Glycine max · TaxonPublic domain · Wikimedia Commons ↗
Zea mays subsp. mays
Zea mays subsp. mays · TaxonDominicus Johannes Bergsma · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“before 2005 more than forty years of field research with corn and soybean conducted at many locations across the state had measured a yield response to S fertilizer application only three times out of approximately 200 trials”

✓ located verbatim in the source · abstract, characters 601–826 · show in text ↑
t0

“Iowa”

✓ located verbatim in the source · title, characters 33–37 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Sulfur fertilizer improved alfalfa coloration, growth, and forage yield in multiple fields.

Taxon
alfalfaMedicago sativae0
Treatment
S fertilizer applicatione0
Outcome
alfalfa plant coloration, growth, and forage yielde0
Direction
improvede0
Setting
multiple fieldse0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Medicago sativa
Medicago sativa · TaxonDrepanostoma · CC BY 4.0 · iNaturalist ↗

Verbatim

e0

“research in multiple fields documented improved alfalfa plant coloration, growth, and forage yield with S fertilizer application”

✓ located verbatim in the source · abstract, characters 1141–1269 · show in text ↑

sulfur atom · yield · Medicago sativa (alfalfa)Results differ

16 papers: 11 positive, 5 negative or no effect

10 papers in the same direction as this paper · 5 in the opposite direction

  1. no effect
  2. no effect
  3. no effect

12 papers more in this group

See all 16 papers →

fertilization · yield · Medicago sativa (alfalfa)Positive and negative results

184 papers: 151 positive, 33 negative or no effect

150 papers in the same direction as this paper · 30 in the opposite direction · 3 reporting no difference from an alternative

  1. negative
  2. no effect
  3. no effect

180 papers more in this group

See all 184 papers →

Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.