When teak (Tectona grandis L. f.) is planted in sandy soil in Northeast Thailand, its growth is suppressed by low pH, poor fertility, and low water holding capacity. To examine materials capable of increasing water holding capacity and nutrients in the soil in order to improve teak growth, we conducted an experiment with teak seedlings. We used perlite and added at a rate of 4% to sandy soil from northeast Thailand. Teak seedlings were potted in these soils and raised from July 2013 to July 2014. We compared growth, photosynthetic rate, leaf water potential, and concentrations of elements in plant organs between the perlite and no addition (control) treatments.
Water content in the soils was increased with the perlite treatment from December 2013; however, this effect decreased after March 2014. Comparing the growth traits of the teak seedlings, perlite treatment produced larger growth and promoted the uptake of phosphorus, calcium, and magnesium. These trends originated from the presence of these nutrients in perlite. We concluded that perlite had a role as a fertilizer, and was a useful material to improve teak growth in sandy soil.