Sulfur Trials Show Varied Response
There’s been much discussion of sulfur deficiency in Iowa in recent years, but few farmers have actually observed it in their field.
For the past 3 years, growers working with the On-Farm Network® have been using replicated strip trials to look at sulfur-containing fertilizers in an attempt to determine whether these can bring up yields on fields where soil type, management and other conditions might make them prone to sulfur deficiency. We would not expect to see a response on fields where manure has been used recently, or, in general, on soils with more than 2% organic matter content.
Shown here are photos from one of the trial fields in 2011, where visual differences were observed early in the growing season. The field is located in Black Hawk County, with a mix of mostly Finchford, Sparta, Dickinson and Chelsea sandy loam soils.
Individual plant photos here were typical for the differences between the treated and untreated strips. Aerial imagery in early July and again in August continued to show differences between the strips. It’s quite easy to pick out the strips in these images.
The visual differences seen in this particular trial were greater than those from other 2011 trials. Soil and tissue sample analysis in August showed that sulfur levels for both were higher in the treated strips than in the untreated strips in most of the trials. Yield response for all trials with sulfur products ranges from 2 to nearly 8 bu. per acre. We expected to see a difference in the trial pictured because of the sandy, low organic matter soils.
Click here for additional information on 2011 crop nutrient trials. When the new screen opens, scroll down the page to the Plant Nutrition section.