Effect of Potassium Fertilizer Types and Rates on Peanut Growth and Productivity on Coastal Sandy Soil in South Central Vietnam. International Potash Institute (IPI)

ABSTRACT

Two potassium fertilizer types (potassium chloride {KCl} and potassium sulfate {K2SO4}), at five distinct doses (0, 30, 60, 90, and 120 kg K2O ha–1) were applied to determine a suitable potassium (K) fertilization approach for a new peanut cultivar, LDH.09, especially selected for peanut cultivation on the saline coastal sandy soils of Binh Dinh province, Vietnam. While neither fertilizer significantly influenced peanut growth and yield parameters under the majority of doses, the effect of dose on yield was dramatic, particularly at low doses (30 and 60 kg K2O ha–1), illustrating a saturation curve. The economic optimum was already reached at a dose of 30 kg K2O ha–1. Excluding a significant rise in soil pH due to liming, soil fertility remained very low at the end of the trial, indicating an unsustainable crop system. These results suggest that most of the applied K was wasted before reaching the plants’ roots. Therefore, alternative approaches to fertilization for highly productive and sustainable peanut crop systems in Binh Dinh, should be considered. This could include splitting the K dose into many frequent applications, and/or employing fertilizers which exhibit slow-release nutrient properties.

Keywords: Acid soil; Arachis hypogaea L.; potassium; saline; sand.