by Jim Camberato and Shaun Casteel
Agronomy Department, Purdue University

Severe sulfur (S) deficiency in our wheat experiment (thankfully a S response trial) at the Southwest Purdue Ag. Center in Vincennes, Ind., has prompted us to alert farmers and their advisers to be aware of the potential for S deficiency in wheat as well as corn and alfalfa later in the season.

Sulfur deficiency of crops will become more common in the future

Atmospheric S deposition used to be substantial enough to satisfy crop needs. However because power plants have reduced S emissions, crops are reliant more on soil S supply. The incidence and severity of S deficiency is expected to increase as a result and applying fertilizer S will be necessary to provide sufficient S. Sulfur deficiency is most likely in sandy soil with low organic matter, but can also occur in silt loam soil with moderate organic matter levels. No-till systems and heavy residue are also thought to increase the chance of S deficiency.

Identifying sulfur deficiency

Sulfur-deficient crops typically have an overall yellow appearance similar to N deficiency (Photo). However S is not as mobile in the plant as N, so lower leaves do not show more severe deficiency symptoms than the upper leaves unlike N. In corn, S deficiency may also cause leaf striping in addition to an overall yellow color. Sulfur deficiency is more likely in corn, wheat, and alfalfa than in soybean. If S deficiency is misdiagnosed as a N deficiency, the application of fertilizer N will make S deficiency worse, so tissue sampling is recommended to positively identify the limiting nutrient.

(Full article here.)

SOURCE: Purdue University.