This experiment was carried out in a greenhouse at Faculdade de Ciências Agronômicas UNESP, Botucatu, São Paulo, to evaluate early growth and root system formation of soybean in the presence of Guinea and forage sorghum crop residues. The experimental units consisted of PVC tubes (rhizotron) with the capacity of 16 dm-3 of soil. The experimental design was a 2 x 3 factorial in complete randomized blocks, with four replicates. Guinea sorghum straw left on the soil surface reduced soil base saturation. Residues of both sorghum varieties left on the soil surface reduced soybean growth. This was also observed in the presence of forage sorghum root system, alone. Guinea sorghum residues, mainly the straw left on the soil surface, decreased soybean nutrient accumulation as well as root and shoot growth.
allelopathy; root growth; crop rotation
