MATERIAL AND METHODSThe experiment was carried out in a greenhouse with soybean plants cultivated in plastic pots of 7 L capacity from November 2016 to March 2017. The substrate used to fill the pots consisted of soil from B horizon, sand, and cattle manure in the proportion of 3:1:1 (v/v/v). The soil was classified as a dystrophic red-yellow argisol of clayey texture. Its chemical and physical characteristics are presented in Table 1. The liming and soil fertilization were performed by adding 1.0 kg of dolomitic limestone, 0.5 kg of K2O and 5.0 kg of P2O5 m-3 in the form of limestone, potassium chloride, and single superphosphate, according to the general recommendation for the substrate preparation (Ribeiro, 1999).