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 SO 4 –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.