Effects of Bentonite, Charcoal and Corncob for Soil Improvement and Growth Characteristics of Teak Seedling Planted on Acrisols in Northeast Thailand

Masazumi Kayama,Sutjaporn Hongthong,Reiji Yoneda,Wilawan Wichiennopparat,Tosporn Vacharangkura,Suchat Nimpila,Woraphun Himmapan,Iwao Noda

doi:10.3390/f7020036

Masazumi Kayama, Sutjaporn Hongthong + Show 6 more

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https://doi.org/10.3390/f7020036

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Abstract

When teak (Tectona grandis L. f.) is planted on acrisols in Northeast Thailand, its growth is suppressed by low pH, infertility, and low water holding capacity. To examine materials capable of increasing water holding capacity in soil and improving teak growth, we conducted an experiment with teak seedlings. We selected bentonite, charcoal, and corncob and added these materials at a rate of 4% to sandy soil from northeast Thailand. Teak seedlings were potted on these soils and raised from July 2013 to July 2014. We compared growth, photosynthetic rates, leaf water potential, and concentrations of elements in plant organs among bentonite, charcoal, corncob, and no addition (control) treatments. Water content in the soils was increased for the bentonite and charcoal treatments. Teak seedlings potted in these two conditions did not suffer from drought stress. Comparing the growth traits of the teak seedlings, the charcoal treatment produced larger root growth and promoted the uptake of phosphorus and potassium, whereas the bentonite treatment did not show positive effects on growth or nutrient acquisition. In contrast, the corncob treatment decreased water content in the soil, and teak seedling growth was suppressed. We concluded that charcoal was a useful material to improve teak growth in sandy soils.

Highlights

Teak (Tectona grandis L. f) is one of the most valuable timber species in tropical regions, and it has been planted in various countries [1]
To verify the effects of these three materials, we examined the ecophysiological traits of teak seedlings, (1) the growth characteristics of seedlings, (2) leaf water potential, (3) photosynthetic rate, and (4) concentrations of elements in plant organs
When teak seedlings were potted in sandy soil mixed with charcoal, root growth was accelerated despite the absence of fertilization

Summary

Introduction

Teak (Tectona grandis L. f) is one of the most valuable timber species in tropical regions, and it has been planted in various countries [1]. The natural distribution of teak is in tropical deciduous forests in India, Myanmar, Thailand, and Laos [1,2]. In natural teak forests, there are obvious rainy and dry seasons, and the leaves of teak fall in the dry season [1,3,4]. Water is one of the most important factors for the growth of teak. The period of the rainy and dry seasons affect the growth of teak, and increasing the length of the dry season shortened the leaf foliation period [4,5]. Teak consumes large amounts of water for its growth. The majority of the roots are concentrated within a soil depth of 60 cm [1,11], and ground water at this

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