No. 22 Article 8/September 4, 2009

Sulfur Research: We Need Your Help

Volunteers are needed throughout Illinois to participate in on-farm research measuring corn response to sulfur applications. While not widespread, the frequency of sulfur deficiency in corn has increased over the years since it was first seen in Illinois more than three decades ago. This increased frequency is likely the result of several factors, including less use of sulfur-containing fertilizers, insecticides, and fungicides; less atmospheric sulfur deposition; greater removal rates by increasing grain yields; increased use of conservation tillage, which may reduce sulfur availability; and fewer livestock operations, resulting in less application of manure.

Soil conditions. We are interested in light-colored soils (less than 2% organic matter, coarse texture, or both) and soils with an eroded phase. However, we would like to characterize sulfur response across the state, so we will also consider other more "traditional" Illinois soils. Fields that have received manure or sulfur applications within the last five years will not be considered.

Equipment, sulfur sources, and timing. Volunteers conducting these trials will follow a simple design applying 0 and 30 lb S/acre broadcast in a uniform portion of the field. A minimum three replications or as many as eight are needed for each field. Figure 1 shows a layout of the treatments randomly assigned within each replication for an eight-replication study. It will be important to georeference or clearly mark the center of each strip using different-colored flags or markers. Strips can be anywhere from 8 to 16 rows wide by 300 to 1,000 feet long. What is important is that the strip size allow accurate rate application and measurement of yield and, if possible, be wider than the harvest strip. However, if the combine is at least 12 to 16 rows wide, it is possible to harvest the strip without having border rows.


Figure 1. Layout of treatments randomly assigned within each replication for an eight-replication study.

Sulfur sources will be limited to ammonium sulfate (NH4)2SO4 (21-0-0-24); MicroEssentials sulfur (ME S) ME S10 (12-40-0-10); and elemental sulfur (0-0-0-90). If the sulfur source contains other accompanying nutrients, the corresponding rates of those nutrients will need to be applied to other treatment strips to avoid a differential response to nutrients other than sulfur. If you use ammonium sulfate you would need to apply 26 lb N/acre to the other strips; if you use ME S10 you would need to apply 145 lb DAP (18-46-0)/acre.

The preferred application time is spring, but if the only time available is fall, we can accommodate that. Most important to us is having as many locations as possible throughout the state to be able to characterize the potential for corn response to sulfur in Illinois.

Measurements for data collection. The only data volunteers will have to provide is the yield for each strip. This information can be collected by yield monitor or from a weigh wagon. Volunteers will not have to take plant or soil samples, but they will need to allow a researcher to visit the strips two or three times during the growing season.

If you are interested in participating (even if you are unsure whether your particular field would fit the study conditions) or if you have questions about how to find sulfur fertilizer or to have the fertilizer applied, please contact me (fernande@illinois.edu; 217-333-4426; Department of Crop Sciences, N-315 Turner Hall MC-046, 1102 South Goodwin Ave., Urbana, IL 61801).--Fabián Fernández

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