Sulfur deficiencies show up in corn crop as atmosphere changes

Dec 31, 2024

While the secondary macronutrient sulfur used to be adequately supplied through atmospheric deposition, times have changed, and we now receive almost zero sulfur via deposition.

Additionally, plant-available sulfur in the soil has been reduced by an estimated 34-86% over the last 20 years. This has led to sulfur deficiency symptoms in corn becoming more common.

Sulfur deficiency in corn is overall a lighter green plant color and chlorotic (yellow) stripes in between the veins (interveinal chlorosis) in the mid- to upper-crop canopy. These symptoms usually appear somewhere around V5 and will be persistent if sulfur deficiency is a problem for the plant.

Soil tests are not a reliable way to predict sulfur deficiency in Iowa soils. Generally, lower organic matter soils (less than 3.5%), sandy soils and those with eroded surfaces are most likely to need sulfur. But in more recent years, sulfur deficiency has appeared on higher organic matter and finely textured soils.

Fertilizing strips or blocks of fields with sulfur to test the crop response in-season is a useful way to evaluate whether a visual response occurs. A visual response in the early vegetative stages of corn is a good indicator of possible yield response and allows time for a side-dress application of sulfur.

Click here to see more...

Video: Dicamba Returns for Georgia Farmers: What the New EPA Ruling Means for Cotton Growers

After being unavailable in 2024 due to registration issues, dicamba products are returning for Georgia farmers this growing season — but under strict new conditions.

In this report from Tifton, Extension Weed Specialist Stanley Culpepper explains the updated EPA ruling, including new application limits, mandatory training requirements, and the need for a restricted use pesticide license. Among the key changes: a cap of two ½-pound applications per year and the required use of an approved volatility reduction agent with every application.

For Georgia cotton producers, the ruling is significant. According to Taylor Sills with the Georgia Cotton Commission, the vast majority of cotton planted in the state carries the dicamba-tolerant trait — meaning farmers had been paying for technology they couldn’t use.

While environmental groups have expressed concerns over spray drift, Georgia growers have reduced off-target pesticide movement by more than 91% over the past decade. Still, this two-year registration period will come with increased scrutiny, making stewardship and compliance more important than ever.