Corn Response to Starter Fertilizer and Broadcast Sulfur Evaluated Using Strip Trials

Abstract

Sulfur fertilization has historically been recommended for corn (Zea mays L.) production in Minnesota only for only coarse‐textured soils. In fields where medium or fine‐textured soils and spatial variation exist, plants have shown chlorosis symptoms indicative of S deficiency. The objectives of this study were to determine the impact of fluid fertilizer combinations containing N, P, and S on early nutrient uptake, corn grain yield, and nutrient removal, and to evaluate various soil factors for predicting S need within fields. Field trials were conducted at four locations, one with a sandy soil and three locations with finer soil textures. Pre‐plant broadcast S was compared with liquid starter N and NP combinations applied with and without S 5 cm beside and below the seed row. Yield was increased by S at two locations. Yield response was not related to soil test SO4–S and decreased with increasing soil organic matter (SOM) concentration. Yield response was greatest when SOM concentration was <20 g kg−1 (0–15 cm), less between 20 and 40 g kg−1, and was not increased when >40 g kg−1. Starter treatments with P consistently increased early plant growth and nutrient uptake and S treatments increased S removal in the grain. The data indicates that when S is applied it can be taken up by corn in greater quantities that are needed for increasing or maintaining grain yield. However, if enough S is available following mineralization from SOM then applied fertilizer S will not benefit yield.