Potassium extracted from ash of para rubber wood: Soil amendment and source of potassium to plant

Abstract

Most soils in Thailand are acidic and have low potassium (K) content, which restricts plant growth. Therefore, it is necessary to improve the soil and apply K fertilizer. Currently, potassium is extracted from rubber wood ash (PEA) to create soil amendment and source of K to plant. This research aims to study the effects of K extracted from rubber wood ash on plant growth and nutrient concentration in plant. Maize was grown in pots with three different treatment conditions: no K application, PEA application at the rates of 100–400 mg K₂O/kg, and KCl application at 100 mg K₂O/kg. The results showed that the growth of maize with both PEA and KCl at the rate of 100 mg K₂O/kg did not show significant differences. The application of PEA not only promoted plant growth, but also increased the nutrient concentration, especially K in the plant tissues. Furthermore, the application of PEA also increased the soil pH value. Therefore, PEA is an alternative source of K for plants and enhances soil pH. In soils with low K content where maize is grown, applying PEA at the rate of 100 mg K₂O/kg is recommended.