Agronomic efficiency of sulfur sources and interaction of sulfur with micronutrients

Abstract

Fertilizer utilization efficiency and nutrient interactions during uptake directly influence grain yield. The objective of this work was to evaluate the agronomic efficiency of sulfur (S) sources on yield and the interaction of S with micronutrient concentrations in soybean. The study involved four S rates (0, 50, 100, and 200 mg kg−1) applied from five sources (S-phosphogypsum, S-Niquelândia rock, S-Araripina rock, S-Grajaú rock, and S-Sulfurgran [90% S0 + 10% bentonite]) in two soil types with different clay concentrations (Typic Ultisol and Typic Oxisol). The efficiency of S sources and rates was determined based on two indices: agronomic efficiency index (AEI) and Sulfurgran equivalent (SEq). The optimal AEI and SEq were observed from the S-Grajaú rock and S-phosphogypsum sources, with the highest values ​​in the Typic Oxisol, while the S-phosphogypsum displayed the highest S recovery rate regardless of soil type. The S sources and rates did not influence the B, Cu, Fe, Mn, and Zn concentrations in leaves and grains.