Tropics
Online ISSN : 1882-5729
Print ISSN : 0917-415X
ISSN-L : 0917-415X
22 巻, 4 号
選択された号の論文の4件中1~4を表示しています
REVIEW ARTICLE
  • Satoshi Yokoyama, Isao Hirota, Sota Tanaka, Yukino Ochiai, Eiji Nawata ...
    2014 年 22 巻 4 号 p. 131-155
    発行日: 2014/03/01
    公開日: 2014/03/01
    ジャーナル フリー
    This paper reviewed some of the major study results published mainly in Japanese on swidden agriculture which was once practiced in Japan. In this review, a focus was placed on the natural environment in which swidden agriculture was practiced, cropping systems, crop cultivation in swidden fields, the transition of swidden agriculture at the end of the disappearing stage, and the utilization of millet cultivated in swidden agriculture. Swidden agriculture of temperate Japan featured cultivation primarily of millet, and was characterized by highly sophisticated and complex cropping systems according to the natural environment, which varied from one region to another. In the 1970s, however, swidden agriculture which had been continuously practiced as a primary means of subsistence in mountainous areas of Japan ceased to exist. Accordingly, the review will primarily focus on studies from the 1950s to 1970s, the post-war period in which a large number of research findings were produced from the perspectives of the humanities and natural sciences. The methodologies and perspectives adopted in the studies on Japanese swidden agriculture are definitely applicable to currently conducted studies of swidden agriculture in tropical regions.
ORIGINAL ARTICLES
  • Tika D. Atikah, Joeni S. Rahajoe, Takashi S. Kohyama
    2014 年 22 巻 4 号 p. 157-167
    発行日: 2014/03/01
    公開日: 2014/03/01
    ジャーナル フリー
    There are physiognomically distinctive forest types in lowland tropics reflecting variation in edaphic conditions. Tree saplings that contribute to forest regeneration are expected to show morphological properties in response to forest environment. However, it remains unknown how sapling properties are similar or different across forest types. We examined architectural and functional traits of forest floor saplings across heath, peat swamp, and mixed dipterocarp forests that characterize lowland forests in Kalimantan, Indonesia. Saplings (150-310cm tall) of 41 species, which represent each forest type, were selected under the canopy of developed forest stands. Among these, we chose one species found in all forest types and two species in heath and peat swamp forests. Significant differences in crown allometries were found across forest types and across species. Saplings in mixed dipterocarp forest had thicker trunk and wider crown at the same sapling height compared to other forests and they had higher specific leaf area, higher mass-based leaf nitrogen content and lower wood density. Heath forest saplings showed lowest leaf nitrogen content and highest wood density. Species with across forest-type distribution showed intra-specific variation in sapling traits, and which was similar to the difference among forest types. We conclude that saplings show morphological response to nutritional and water conditions that characterize forest types.
  • Susumu S. Abe, Toshiyuki Wakatsuki
    2014 年 22 巻 4 号 p. 169-177
    発行日: 2014/03/01
    公開日: 2014/03/01
    ジャーナル フリー
    The present study aimed to examine the influence of termites (Isoptera) on soil clay mineralogy. To this end, we analyzed the clay mineralogy in the mound structures of Macrotermes bellicosus (Macrotermitinae) and in the adjacent natural (termite-free) soil horizons along an inland valley toposequence in central Nigeria, and compared them using differential X-ray diffraction approach. The results indicated that: (i) M. bellicosus modified soil clay mineralogy to minor extent regardless of the substantial enrichment of clay particles in the mound structures; (ii) the mound structures generally had a decreased abundance of quartz balanced with an increased abundance of phyllosilicate minerals such as smectite and/or kaolinite when compared with the adjacent near-surface (Ap2) horizons; and (iii) there was a subtle difference in clay mineralogy between the mound wall and the hive in spite of a large disparity in particle-size distribution. These findings suggest that soil clay mineralogy is not linked to the ecological requirements of M. bellicosus and the apparent change in the clay mineralogy in mound structures is caused by the preferential selection of fine soil particles during the mound construction rather than by a preference among clay mineral species.
FIELD NOTE
  • Hideyuki Noguchi, Cacilda Adélia Sampaio de Souza, Rosiane Oliv ...
    2014 年 22 巻 4 号 p. 179-183
    発行日: 2014/03/01
    公開日: 2014/03/01
    ジャーナル フリー
    Limited information on fine roots is hindering understanding of the geographical-scale variations in belowground carbon stock across the Amazon Basin. Fine root biomass (<2mm in diameter) was studied in the upper Negro River basin of Brazil, where no previous study on fine roots had been reported. Two plots (20×125m), each of which included 3 subplots (20×20m), were set in a tropical moist forest at São Gabriel da Cachoeira, north-western Brazil. The diameter of the trees (dbh>10cm) within each subplot was measured, and fine roots were sampled by coring soils from depths of 0-5, 5-10 and 10-20cm at 12 points in each subplot. The fine root, coarse root, and aboveground biomass in the study forest were estimated as 7.03±0.65 (95% CI), 32.6±15.0 and 253.6±152.7Mg ha-1, respectively. Most of the spatial variance in fine root biomass was accounted among and within the subplot spatial scale of less than 20×20m. The fine root biomass of the study site exceeded the values reported for some tropical forests in the central and eastern Amazon, which suggested regional differences in the fine root biomass in Amazonian forests.
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