The productive chain of agroenergy is responsible for the generation of large quantities of waste. The production of ethanol from sweet potatoes generates by-products that, if not properly disposed of, may cause impacting processes to the environment. In view of the need to reduce the environmental liabilities of sweet potato ethanol production, the objective of this study was to evaluate the potential of the residue application of sweet potato ethanol production (RBD) as a conditioner of soil fertility. For this, the chemical properties of the soil were characterized (P, K+, Ca2+, Mg2+, Al3+, H+ + Al3+, pH e MOS). The experiment was conducted at the UFT - Palmas Experimental Station. The initial soil analysis, collected in depths of 20 and 40 cm, revealed the following values: 67,00 e 42,00 mg/dm-3 de K; 280,00 e 31,70 mg/dm-3 de P; 0,90 e 0,30% de MOS; 3,40 e 0,90 cmolc/dm3 de Ca2+; e 1 e 1 cmolc/dm3 de Mg2+, respectively. After the conventional soil preparation, the cultivation of sweet potato (Bárbara) was planted. Fertilization of chemical and organic potassium was carried out at 40 days and 55 days after planting. The doses applied per lines were: 0% organic fertilizer = 122 g KCL, 25% organic fertilizer = 92 g KCL and 19 L RBD, 50% organic fertilizer = 61 g KCL and 37 L RBD, 75% organic fertilizer = 31 g KCL and 55 L RBD and 100% organic fertilizer = 73 L RBD. The experimental design was a randomized block design in sub-subdivided plots with four replications.Soil samples, for period evaluation, were collected in two periods. The first collection was during the cultivation of sweet potato and the second after harvest of the sweet potato. For the evaluation of the soil parameters in depth, composite samples with depth of 20 and 40 cm were obtained. Therefore, the results showed that organic fertilization presented few advantages in relation to non- fertilization in relation to soil conditioning factors. O efeito da adubação orgânica deve ser avaliado com maior tempo de uso. The use of the residue of the ethanol production of sweet potato as a source of organic fertilization is a complementary alternative in the improvement of soil fertility
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