Physiological and agronomic response of soybean cultivars to soil compaction in the Brazilian Cerrado

ABSTRACT Soil compaction negatively impacts soil physical functions, affecting root growth and crop yield. This study aimed to evaluate different soybean cultivars’ agronomic and physiological performance as a function of compaction in Rhodic Ferralsol under no-tillage (NT) with a clay loam texture in the Brazilian Cerrado biome. The experiment was implemented in Rio Verde, Goias state, central Brazil. The experimental design was a randomized block with a 3x2 factorial scheme with six replications. The first factor corresponded to three soybean cultivars from different maturity groups (MG) identified as super-early (MG = 6.2); early (MG = 6.8), and medium (MG = 7.9). The second factor was the cultivation in compacted and uncompacted soil. The experiment evaluated the soil physical properties: bulk density, total porosity, water content at matric potential -6 kPa, aeration capacity and water and air holding capacity in 0.0-0.1 and 0.1-0.2 m layers, agronomic and physiological traits (gas exchange). Soil compaction negatively affected the agronomic traits of soybean cultivars, with better performance of the medium cycle cultivar. Net photosynthesis, stomatal conductance, and transpiration rates were reduced up to 50% under compaction and were not influenced by cultivars. Our findings suggest that soil compaction negatively affected the performance of soybean cultivars with lower maturity groups reflecting in lower plant height, shoot and root dry mass, number of pods and grain yield. The choice of soybean cultivars with a longer cycle can be an alternative to minimize the adverse effects of soil compaction.