Effect of the application of potassium on the yield of corn (zea mays L.) in La Frailesca, chiapas Mexico / Efeito da aplicação de potássio na produção de milho (zea mays L.) em La Frailesca, chiapas, México

Abstract

In recently soil analysis in La Frailesca Chiapas, it has been detected that most soils have low exchangeable potasium (K) concentrations, therefore maize plants show symptoms of deficiency of this nutrient, which can affect the yield. The maize response was evaluated at four doses of K (0, 90, 180 and 270 kg K2O ha-1) in three locations with non-acid soils. A randomized block design with five replications was used, and potassium chloride (KCl) as a potassium source. KCl was applied by manual broadcasting and was incorporated to the soil 10 and 15 cm deep with a disc harrow. In all three locations a significant positive response was observed (p <0.05) to which a lineal-plateau model was adjusted, with an average increase in yield of 1 964 kg ha-1 (150% higher than without K) with 90 kg K2O ha-1. No response was observed to higher doses. The regression equation for the linear part of the response model is: Yield (kg ha-1) = 3 855 + 22 kg K2O ha-1. The agronomic efficiency of K at the dose of 90 kg K2O ha-1 was higher than the reference range (7 to 15 kg grain.kg-1 K2O). At the same time, this treatment had the highest net benefit and a marginal rate of return of 370%. Under the conditions of this study, the application of 90 kg K2O ha-1 presented the highest yield, economic benefit and agronomic efficiency.