Tropical Volcanic Soils From Flores Island, Indonesia

Hikmatullah Hikmatullah,Kesumo Nugroho

doi:10.5400/jts.2010.v15i1.83-93

Abstract

Tropical Volcanic Soils from Flores Island, Indonesia (Hikmatullah and K Nugroho): Soils that are developed in tropical region with volcanic parent materials have many unique properties, and high potential for agricultural use. The purpose of this study is to characterize the soils developed on volcanic materials from Flores Island, Indonesia, and to examine if the soils meet the requirements for andic soil properties. Selected five soils profiles developed from andesitic volcanic materials from Flores Island were studied to determine their properties. They were compared in their physical, chemical and mineralogical characteristics according to their parent material, and climatic characteristic different. The soils were developed under humid tropical climate with ustic to udic soil moisture regimes with different annual rainfall. The soils developed from volcanic ash parent materials in Flores Island showed different properties compared to the soils derived from volcanic tuff, even though they were developed from th e same intermediary volcanic materials. The silica contents, clay mineralogy and sand fractions, were shown as the differences. The different in climatic conditions developed similar properties such as deep solum, dark color, medium texture, and very friable soil consistency. The soils have high organic materials, slightly acid to acid, low to medium cation exchange capacity (CEC). The soils in western region have higher clay content and showing more developed than of the eastern region. All the profiles meet the requirements for andic soil properties, and classified as Andisols order. The composition of sand mineral was dominated by hornblende, augite, and hypersthenes with high weatherable mineral reserves, while the clay fraction was dominated by disordered kaolinite, and hydrated halloysite. The soils were classified into subgroup as Thaptic Hapludands, Typic Hapludands, and Dystric Haplustands.

Highlights

In Indonesia, the volcanic soils have a total area of 5.4 millions ha or 2.9% of the total Indonesia archipelago (Subagjo et al 2004), whereas in the world the soils occupy about 0.84% of the earth’s surface (Leamy, 1984; Takahashi and Shoji 2002)
The volcanic soils, in most cases are classified into Andisols order but not all volcanic soils are Andisols, depend on the weathering stage and soil forming processes (Shoji et al 1993)
The objective of the study was to characterize the andic properties of the soils which were originated from the parent materials of five volcanoes with different climatic conditions in Flores Island, Indonesia

Summary

Introduction

In Indonesia, the volcanic soils have a total area of 5.4 millions ha or 2.9% of the total Indonesia archipelago (Subagjo et al 2004), whereas in the world the soils occupy about 0.84% of the earth’s surface (Leamy, 1984; Takahashi and Shoji 2002). The volcanic soils have widely distributed along a belt in islands of Sumatra, Java, Bali, Nusa Tenggara, Celebes, and Halmahera. Some studies of the volcanic soils in last decade have been reported, especially from Sumatra (Fiantis and Van Ranst 1997; Alkasuma and Badayos 2003), Java (Arifin and Hardjowigeno 1997; Van Ranst et al.2002; Fauzi and Stoops 2004; Yatno and Zauyah 2008), North Sulawesi (Hikmatullah 2008), and Dompu Sumbawa (Sukarman et al 1993). Many studies of the volcanic soils have been reported from certain countries, such as from Japan (Shoji and Ono 1978), United States (Wada et al 1986; Shoji et al 1988), Mexico (Prado et al 2007), Ecuador (Zehetner et al 2003; Buytaert et al 2007), Costa

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