Impact of sulfur application on soybean yield and quality in New York
Jodi L. Letham, Quirine M. Ketterings, Jerry H. Cherney, T.R. Overton
Abstract
Abstract Sulfur (S) fertilizer is not widely used for soybean [ Glycine max (L.) Merr.] production in the northeastern United States but decreased atmospheric S deposition rates warrant evaluation of S needs for soybean in the region. The objective of this study was to determine the impact of S fertilizers [CaSO 4 and (NH 4 ) 2 SO 4 at 168 kg S ha –1 ] on soybean grain yield, crude protein (CP), S content, N/S ratio, and crop S balances. Thirteen on‐farm trials were conducted in New York in 2017–2019 using a randomized complete block design in three to six replications. Tissue analysis at early bloom and full maturity did not suggest an S limitation; N/S ratios were between 14:1 and 18:1 and tissue S at early bloom ranged from 3.10 to 4.36 g kg –1 . These findings were consistent with the lack of increase in grain yield with S addition, independent of S source. Addition of S did not change seed CP or S concentration although, averaged across trials, the whole plant S content at maturity was slightly higher when S had been applied. Negative partial balances (crop removal – S deposition) showed considerable soil contribution to S uptake. Soil organic matter (SOM), however, was not a good indicator of soil S supply. Due to lack of a response to S, critical soil test S levels could not be determined. We conclude S is not limiting soybean grain yield currently. Continued monitoring is needed as partial balances suggest S may become deficient over time.