1. Overview of S Management & Related Usefulness of Soil Testing David H. Hardy Section-Chief, Soil Testing Agronomic Division, NCDA&CS SERA 6 Meeting June 21, 2011

2. Ordinary superPO 4 -2 (0-20-0) not used –12% S Higher yields via varieties and management = more S demand Cleaner air due to air quality regulation Increased Importance of Today

3. Sulfate Wet Deposition Trends NADP database - current eastern NC estimate (wet + dry deposition: approx 8 lb S/ac/yr)

4. IPNI 2010 Soil Summary

5. Subsoil S Reserves Subsoil where topsoil not managed –68 ppm S Subsoil where topsoil managed –138 ppm S Hardy MS thesis, 1983

6. Sulfur Deficiency Sulfur Deficiency Symptoms

7. Sulfur Deficiency Sulfur Deficiency Symptoms

8. Plants are yellow and stunted.

9. Soil Sulfur – Corn Yellow n = 37, mean = 23 Green corn: S-I = 30

10. Plant Tissue Levels Yellow corn 0.14% S N:S = 26 Green corn 0.18% S N:S = 22

11. S Studies 2005 & 2006 Validate plant response to soil S levels using M3 for both wheat and corn Responsive and nonresponsive site –Based on surface M3 = 12 ppm S source- pelletized gypsum S rates- 0, 11, 22, 45 kg ha-1 –Applied broadcast after planting for corn Split for wheat at two higher rates

12. S Studies 2005 & 2006 Soil samples at study initiation and V6 –Depth A: 0 to 10 cm- NT; 0 to 15 cm- CT –Depth B: 10 to 20 cm- NT; 15 to 30 cm- CT Plant tissue at V6 and VT Yield

13. Soil data for 2005 locations. Location Surface Texture Taxonomic NameInitial Soil S Depth ADepth B ----mg dm -3 ---- Bertieloamy sandTypic Udipsamment1520 Edgecombe-1f. sandy loamAquic Paleudult1224 Edgecombe-2*loamy sandArenic Kandiudult1312 Greene*fine sandArenic Hapludult1311 Hydemucky sandy loam Umbric Endoudalf1420 Martinf. loamy sandAquic Paleudult1614 * Predicted responsive site based on S in topsoil being ~ 12 mg dm -3 or less.

14. Hyde Co, Armstrong Farms, muck, 2005 (only significant response was in V-6 plant tissue S)

15. a b ab Edgecombe-2, 2005 Soil S 0 – 9 10 – 10 20 – 11 40 –15

16. Greene, 2005 a a a a Soil S 0 – 11 10 – 13 20 – 13 40 –18

17. Bladen Co., 2006 a b a a Soil S 0 – 10 10 – 10 20 – 11 40 –10

18. S Studies 2005 & 2006 Overview 2005, 1 of the 2 predicted sites responded –Greene Co. data is bothersome 2006, 1 in 5 predicted sites responded –Weed problems, Organic soil may have mineralized S…?? Plant nutrition improved @ V6 on both responsive and nonresponsive sites

19. Recommendation?? Similar Quandary as Nitrogen Highly leachable as nitrate but subsoil S Mineralization / immobilization issue However, possibly overlooked, unlike N Easy to acquire value from ICP, unlike N

20. Current S Recommendations Soil critical level: 12 ppm = 25 S-I –15 to 25 lb per acre of S depending on soil class Know your soils –Consider S fertilizer if 18+” surface sand Plant tissue sample