Sulfur Management for Corn Growth with Conservation Tillage

Abstract

Reduction in soil disturbance associated with conservation tillage planting systems suggests that it is important to evaluate management practices for use of S for corn (Zea mays L.) grown in these planting situations. Evaluation of source, placement, and rate of S applied has not been the focus of past research. In this study, two S fertilizers [21‐0‐0‐24 (ammonium sulfate), 12‐0‐0‐26 (ammonium thiosulfate)] were applied at rates to supply 0, 6.7, 13.4, and 20.1 kg S ha−1 either in contact with the seed at planting or in a band near the seed at planting. Soil texture varied from loamy fine sand to silty clay loam at the experimental sites. Corn emergence was reduced when 12‐0‐0‐26 was placed in contact with the seed at sites with a loamy fine sand and sandy loam texture and soil was dry at time of planting. Stand reduction was most severe when 12‐0‐0‐26 fluid material was used at rates to supply 13.4 and 20.1 kg S ha−1 Placement maintaining soil between seed and fertilizer had no negative effect on emergence. When placed in a band near the seed, both S sources had an equal effect on yield. Reduction in emergence due to 12‐0‐0‐26 in contact with the seed had a negative effect on grain yield. Application of fertilizer S increased yield at all sites except where the texture was a silty clay loam. Optimum rate of fertilizer S was either 6.7 or 13.4 kg S ha−1 and varied with site. The response to fertilizer S on the silt loam soil suggests that inadequate S is released from soil organic matter via mineralization in conservation tillage planting systems.