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.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 2
Claim · model-written summary
Before 2005, sulfur fertilizer increased yield in only three of about 200 Iowa corn and soybean trials.
- Taxon
- corn and soybean
Glycine maxZea mays subsp. mayse0
- 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.

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”
t0“Iowa”
Claim · model-written summary
Sulfur fertilizer improved alfalfa coloration, growth, and forage yield in multiple fields.
- Taxon
- alfalfa
Medicago 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.

Verbatim
e0“research in multiple fields documented improved alfalfa plant coloration, growth, and forage yield with S fertilizer application”
The same questions in other papers
sulfur atom · yield · Medicago sativa (alfalfa)Results differ
10 papers in the same direction as this paper · 5 in the opposite direction
- no effect
- no effect
- no effect
12 papers more in this group
See all 16 papers →fertilization · yield · Medicago sativa (alfalfa)Positive and negative results
150 papers in the same direction as this paper · 30 in the opposite direction · 3 reporting no difference from an alternative
- negative
- no effect
- 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.