Evaluation of the effect of different doses of potassium on yield of soybean

The soybean culture has a significant role for the Paraná state, not only due the facto of being the second lasgest producer, but also for having climate favorable to planting.The adequate supply of Potassium has showed to be a complicate issue due to problems like leaching on sandy soils on the northeast of Paraná and its importance for the good development of the soybean. This paper sought to evaluate how availability of Potassium supplied in the ground after the plant germination through mineral fertilization by cover, Potassium with dosage of (0, 60, 90 and 120 kg ha-1), through factors such as production per hectare, number of pods per soybean plant and thousand grain mass. Factors that could influence the development of the plants such as nutrition, water availability, plague control and diseases were controlled with corrective and regular fertilizations, sprinkler irrigation and chemical and cultural control for pests. It was verified significative results where was used the dose of Potassium chloride fertilizer, in the control treatment were symptoms of culture deficiency and low productivity. The best dose was the 90kg ha-1 ofPotassium chloride and it was found the relation between the number of pods and productivity.