By George Silva
Soybean response to supplemental sulfur is the topic of a field investigation in Perry in 2013.
An on-farm research project is being conducted where a liquid starter fertilizer Access containing 17 percent S was applied to soybeans. The recommended rate was 2 quarts/A band applied 2X2 inches at planting. This will place about a pound of S per acre in a band close to the seed.
Plots were 30 feet wide (12 rows) and 1,553 feet long and the treated plots are being compared with untreated plots side by side. Treatments were randomized and replicated five times. The soil was a Boyer sandy loam with low organic matter. The soybean variety was Syngenta 29-V2, a 2.6 maturity group Roundup Ready variety with Avicta and Vibrance seed treatments.
Recent research has suggested potential S deficiencies in corn and soybeans in the north central region. Atmospheric deposition of S has considerably decreased following the Clean Air Act. Organic matter is an important source of S and when it decomposes, S is released as a sulfate ion into the soil
solution. Michigan State University Extension recommendations suggest that sulfur deficiencies are most likely to occur on coarse-textured soils with low organic matter. Sulfur is not mobile within the plant, so deficiency symptoms appear in the new growth (early season general chlorosis). Plants sometimes grow out of this condition as roots expand and penetrate the soil.
During the season, sulfur and other micronutrient uptake of soybeans will be monitored by analyzing the first trifoliate leaf tissue. Soil testing for S is not as reliable as tissue analysis. Please refer to the MSU Extension bulletin E-486, "Secondary and micronutrients for vegetable and field crops," for S sufficiency range on soybeans. The most important aspect of this trial is to ascertain if the addition of sulfur would result in a consistent yield increase on coarse-textured soils.
This study was funded by the Michigan Soybean Promotion Committee. For more information, visit their website. To contact an expert in your area, visit online, or call 888-MSUE4MI (888-678-3464).
Silva writes for Michigan State University Extension