Thanks to growers’ collaboration and help from Superior Ag, we collected plant tissue samples from 12 watermelon fields at different crop growing stages in Southern Indiana in the 2020 season. In a previous article, we discussed results about magnesium and potassium. In this article, we will discuss another nutrient, Sulfur (S).
Sulfur deficiency has become an issue in corn production in Indiana. This is attributed to decreased emissions of S from coal-fired power plants that has lead to the decreased deposition of S to soils. As S from the atmosphere is reduced, S from fertilizer application and microbial activity on soil organic matter is becoming increasingly important. As sandy soils in our area are generally low in organic matter, it is reasonable to expect the soils may be potentially low in S.
Is S deficiency a concern in watermelon production in southern Indiana? In the current survey, we noticed that S content in dry watermelon leaf samples ranged from 0.3 to 0.5%. This is within the adequate range based on recommendations from Bryson et al., Plant Analysis Handbook III. The current survey revealed good news about S in watermelon production, but it is important to understand the survey number is not large enough to cover the entire region, and the survey was only conducted in one year. We will continue the survey in the coming years and watch closely for the S levels.
Although we did not detect S deficiency in the watermelon samples this year, watermelon growers should aware that sulfur deficiency was reported on watermelons in Maryland. In watermelons, symptoms appear as a light green or light yellowing of newer leaves (Nitrogen deficiency has yellowing on older leaves first). Overall, plant growth and development are stunted. Soil pH and the presence of other nutrients have little influence on S absorption, thus S deficiency may show up at a wide range of pH levels. If you suspect the S deficiency is a concern in your watermelon field, please contact me at guan40@purdue.edu, and we will conduct a plant tissue test to confirm this.
Resources:
Camberato, J. et al., Yield response of corn to sulfur fertilizer research update. 2020. < https://www.agry.purdue.edu/ext/corn/research/updates/CornRespSulfur.pdf>
Burst, J. 2019. Sulfur deficiency in sweet corn and watermelons. 2019. < https://sites.udel.edu/weeklycropupdate/?p=13894>