Impact of sulfur application on soybean yield and quality in New York

Abstract

AbstractSulfur (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 [CaSO4 and (NH4)2SO4 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.