Jarrod O. Miller, Extension Agronomist, jarrod@udel.edu
Jarrod Miller (funded by Maryland Grain Producers https://marylandgrain.org/)
As anions, sulfate (SO4) and boron (B) leach easily from the soil surface (particularly sandy loams), potentially leading to sulfur (S) deficiencies in grain crops. In this study we observed whether increasing S and B fertilizer applications affected tissue Nitrogen (N), S and B concentrations as well as overall yield. Sulfur was added in small amounts as starter, with an additional treatment with S in sidedress. Then the same treatments were repeated with 0.5 lbs of B at sidedress (Table 1).
| Table 1: Treatments applied each year as starer | |||||
| Starter + Sidedress | Starter | Sidedress | Total N (lbs/acre) | Total S (lbs/acre) | Total B (lbs/acre) |
| 1 – (N + N) | UAN | UAN | 230 | – | – |
| 2 – (N/S + N) | Nsul | UAN | 230 | 4 | – |
| 3 – (N/S + N/S) | Nsul | Nsul | 230 | 4+18 | – |
| 4 – (N +N/B) | UAN | UAN + B | 230 | – | 0.5 |
| 5 – (N/S + N/B) | Nsul | UAN + B | 230 | 4 | 0.5 |
| 6 – (N/S + N/S/B) | Nsul | Nsul + B | 230 | 4+18 | 0.5 |
Over the three years (2021-2023) of the study, yield did not increase based on S or B additions (Figure 1). There was an upward trend with yield for B additions in 2023, but it was not significant. This trend was not observable in 2021 or 2022. Even within our sandy coastal Delmarva soils, neither S or B appeared yield limiting within this study.
Additionally, neither N or S varied within the corn ear leaf tissue, although they were lowest in 2023 (data not shown). However, B did increase in the corn leaves with fertilizer applications, particularly for the treatment with both S and B additions at sidedress. This treatment had the highest B concentrations in the ear leaf each year (Figure 2). Although neither B or S had an effect on yield in this study, if you are experiencing a B deficiency, additions with S at sidedress may assist in plant uptake.
Figure 1: Yields each season (2021, 2022, 2023) across the six treatments of N, S, and B (starter + sidedress).
Figure 2: Tissue boron (ppm) each season (2021, 2022, 2023) across the six treatments of N, S, and B (starter + sidedress). Only the statistically highest B concentrations (a = 0.10) within each year are marked with a star.