Desenvolvimento de plantas de soja sob o uso de adubação mineral e biofertilizante obtido da manipueira

The effect of application of mineral fertilization and increasing doses of biofertilizers obtained from the anaerobic digestion of cassava wastewater in the development of soybean plants is evaluated. Assay was conducted in a protected environment at the Universidade Federal do Parana (UFPR), campus Palotina, between October 2015 and March 2016. Totally randomized design comprised six treatments composed of the following doses and applied in five replications: mineral fertilization 02-20-20 (NPK) and 0, 40, 80, 120 and 160 kg ha-1 of K2O. The following parameters were evaluated: height, Falker Chorophyll Index (FCI), stalk diameter, number of ramifications, dry mass of aerial and root sections, number and mass of grains and oil rate. Mineral fertilization was greater than organic fertilization of FCI and stalk diameter. At the end of the cycle, difference existed only in the number of grains, with higher rate in dose 160 kg ha-1 of K2O. Oil rate in grains was lower in mineral fertilization and lower doses of K2O, suggesting that higher doses provided a positive effect. Biofertilizer of anaerobic digestion of cassava wastewater may be coupled to mineral fertilization for costs reduction and the correct use of the waste.