Sulfur fertilization in soybean: A meta-analysis on yield and seed composition

Sulfur (S) deficiency has been recently reported in soybean [Glycine max (L.) Merr.] producing regions across the United States. However, field studies have often failed to demonstrate a strong relationship between yield and S fertilization and generally attributing the lack of yield response to unfavorable weather and high soil S supply. In addition, only a few reports described seed composition changes due to S availability under contrasting field conditions. Therefore, our goals were (i) to implement a meta-analytic model to quantify the effect of S application at different growth stages on yield and seed concentration of protein, oil, essential non-S amino acids, and S amino acids (SAA, cysteine and methionine); ii) identify environmental factors underpinning the response of S to these plant traits. Field experiments were carried out from 2017 to 2019 growing seasons with a total of 44 unique site-years conditions across 18 locations in 8 states. Mineral S fertilizer (sulfate/ elemental S) was supplied depending on the study at sowing, vegetative and/or reproductive stages. A random-effects multilevel meta-analysis was conducted. The effect sizes compared yield and seed composition responses relative to the unfertilized control. A principal component analysis (PCA) separated distinctive environmental conditions and a sub-grouped meta-analysis with the main environmental factors was later executed to understand the response of the plant traits with those factors. Seed protein concentration increased by 0.3 % when S was applied at sowing. The concentration of SAA increased by ca. 1% regardless of the fertilization timing. Sites exposed to drought stress (18–29% reduction of potential transpiration) neither presented changes in yield nor seed composition due to S fertilization. Soils with organic matter between 25 and 32 g kg-1 (medium cluster) displayed significant responses to S application. This research brings extensive data and provides a comprehensive analysis of weather and soil attributes influencing soybean yield and seed composition responses to S availability.Fil: Fróes de Borja Reis, André. Kansas State University; Estados UnidosFil: Moro Rosso, Luiz H.. Kansas State University; Estados UnidosFil: Davidson, Dan. No especifíca;Fil: Kovács, Péter. University of South Dakota; Estados UnidosFil: Purcell, Larry C.. University of Arkansas for Medical Sciences; Estados UnidosFil: Below, Frederick E.. University of Illinois. Urbana - Champaign; Estados UnidosFil: Casteel, Shaun N.. Purdue University; Estados UnidosFil: Knott, Carrie. University of Kentucky; Estados UnidosFil: Kandel, Hans. North Dakota State University; Estados UnidosFil: Naeve, Seth L.. University of Minnesota; Estados UnidosFil: Carciochi, Walter Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; ArgentinaFil: Ross, Willian J.. University of Arkansas for Medical Sciences; Estados UnidosFil: Rampazzo Favoretto, Vitor. University of Illinois. Urbana - Champaign; Estados UnidosFil: Archontoulis, Sotirios. ;Fil: Ciampitti, Ignacio Antonio. Kansas State University; Estados Unido