Productivity of soybean crop after fertilization with normal and polymer-coated potassium sources

摘要

The adoption of different fertilizer application methods should consider the operational, agronomic and economic aspects. The objective of this work was to study the fertilization response with potassium in the soybean crop at different times of application and different potassium sources in an Eutroferric Red Latosol. The experiment was carried out in the municipality of Formosa do Oeste-PR. The design was in a randomized block in a factorial scheme (2 × 5) +1, with 2 potassium sources: normal KCl (KCl) and polymer-coated KCl (KCl-polymer), the KCl doses were adjusted to 40 kg ha -1 of K2O, the second factor refers to the splitting of K2O dose in five application times: T1, application of K2O was nine days before sowing, T2 application split up being ? of the dose nine days before sowing + ? of the dose of K2O at sowing, T3 application of the total dose of K2O at sowing, T4 ? of the dose at sowing + ? at the V3 phenological stage of the crop, T5 application of K2O was total at the V3 stage of the crop. And an additional witness, without K2O application. KCl-polymer was more efficient for application to the haul before sowing the crop. The fertilization with KCl was better when applied at the V3 stage of the crop. Fertilization with KCl-polymer resulted in higher K content in the leaf, higher efficiency of fertilizer use reflecting in higher productivity.