Sustainable agriculture on the tropical acidic soil

本研究的目的是提出在热带酸性土壤地区实施可持续农业的一些策略。我们选择进行这个项目是使用有机材料，通常是在热带地区的日常生活中扔掉。东南亚被选为目标地区。在东南亚国家中，渔业非常重要且发达。因此，本研究尝试利用渔业废弃物作为酸性土壤的改良材料。鱼粪的成本几乎是免费的，而且鱼粪中含有高浓度的氮和磷。由于椰糠中纤维含量高，持水性好，因此也被选为改良材料。这种材料的成本很低，足以应用于农业领域。在田间试验中，作物（玉米、甘薯等）施用这些材料的田地中的产量比对照田地中的产量高得多。在日本也进行了田间试验，使用的土壤具有与热带酸性土壤相似的特性。在日本的田间试验中，作物（犹太骨髓、玉米等）材料应用领域的产量也较高。土壤总脂肪酸和TRFLP的分析表明，在施肥的土壤中，微生物植物群发生了特殊的变化。新开发的分析预计将用于土壤质量评价。

The aim of this study is to present some strategy to practice sustainable agriculture in the tropical acid soil area. Our choice to proceed this project was to use organic materials that are usually threw out in daily life in the tropical area. Southeast Asia was selected as target area. In the southeast Asian countries the fishery industry is very important and well developed. So, in this study we tried to use the waste from fishery industry as an amendment material for acidic soil. The cost for the fish waste was almost free, and the material contains high concentration of nitrogen and phosphorus. The coconut dust was also selected as an amendment material because this material contains much fiber and has high water holding capacity. The cost for the material was cheap enough to apply into agricultural fields. In the field experiment the crop (maize, sweet potato etc.) yields became quite higher in the fields applied with these materials than in the control fields. The field experiment was also carried out in Japan using soils that have similar characteristics to the tropical acidic soil. In the fields experiment in Japan the crop (Jew's marrow, maize etc.) yields were also higher in the materials applied fields. The analyses of total fatty acids and TRFLP for the soils showed specific changes of microbial flora in the materials applied fields. The newly developed analyses are expected to be used for soil quality evaluation.