Evaluation of soybean genotypes grown under soil compaction

Abstract

AbstractSoil compaction has caused negative impacts on soybean productivity due to the excessive use of machinery and heavy agricultural implements in the cultivation areas. Effects of two levels of soil compaction were investigated on 60 soybean genotypes in a field experiment. Soil properties, weather conditions in the region and changes in agronomic characteristics of the crop were evaluated. The genotypes were divided into three groups according to the relative maturity group (RMG) and classified according to stress susceptibility. Compaction increased soil density and soil mechanical resistance to penetration, varying according to the registered rainfall regime. The genotype responses to compaction in the three groups, in general, were increased seedling emergence (EME), initial height (IH), number of nodes (NN), shoot dry matter (SDM), and final height (FH) of the plants. However, there was a reduction in the relative growth rate (RCR), in the number of pods (NP), and in grain yield (PROD). From the calculation of the stress susceptibility index (SSI) it was possible to identify tolerant and sensitive soybean genotypes to soil compaction stress. SSI and the relative trait change index (RTC) indicated the responses that the tolerant genotypes present under conditions of high mechanical impedance. Therefore, soil compaction provides greater seedling emergence and vegetative growth, but significant losses in soybean yield. Soil compaction‐tolerant genotypes show smaller reductions in relative growth rate, absolute growth rate, final height, number of pods, and grain yield.