Hildeu F. Assunção1, Tatiane M. Lima1 and Gerrit Hoogenboom2, (1)Campus Jatai, Federal University of Goias, Jatai, GO, Brazil (2)Irrigated Agriculture Research and Extension Center, Washington State University, Prosser, WA
We conducted an experimental test with peanut using a two-factor with three levels of potassium (0, 40 and 80 kg.ha-¹ K2O) and four levels of phosphorus (0, 40, 80 and 120 kg.ha-¹ P2O5) taking into account two types of soil under Brazilian Cerrado: Oxisol clayey and sandy Oxisol, and two sowing times: season and off-season. During the conduct of experiment, we measured weekly, the fraction of canopy cover, while in the end, we measured the production parameters. With this study we verified that the effect of potassium on the fraction of canopy cover as well as on the yield of peanuts did not differ significantly from the control (K2O = 0 kg.ha-¹, P2O5 = 0 kg.ha-¹) in both types of soil and planting seasons. On the other hand, starting 30 days after sowing until maturity, we noticed an effect caused by phosphorus fertilization in both the fraction of canopy cover and yield of peanut. Thus, we conclude that, for the Oxisoil of Brazilian Cerrado, the economic level of fertilizers that provide greater fraction of canopy cover and higher yield for peanuts is 88 kg.ha-¹ phosphorus, plus 43 kg.ha-¹ of potassium.