Developing an agriculture system with built-in water purifying mechanism in urban peripheries of Southeast Asian large cities

本研究旨在通过从农学和社会科学的角度定量阐明农业活动引起的环境负荷的实际状况，并通过确定氮/磷肥的动态变化，为热带亚洲大城市地区的城市外围地区建立可持续农业收集基础数据。2002年8月，我们在Nakonchaise盆地进行了初步调查，选择了覆盖Nontabri、Nakonchaise和Suphanburi地区的样地，并选择了邦兰县和Songpinon县作为候选区。还确定了四种种植模式：(1)水稻种植，(2)池塘蔬菜种植，(3)水稻水田种植，(4)河流水田种植。2003年和2004年，农民对样地进行了耕作记录，并开始对月度土壤和水样和半年度…进行采样更多来自不同深度的早期土壤样本。这些调查表明，几乎所有作物和种植模式的经济效益都很高。研究还发现，农民会根据以前种植的作物以及作物是否被淹来调整化肥和堆肥的数量。对于所有作物和所有作物季节，杀虫剂的成本高于杀菌剂的成本。雇工从事整地、播种、间伐、收割和打包等耕作活动。8月和3月的土壤数据显示，几乎所有农田和河流底泥的无机含量都很高。特别是，8月份的样本比3月份的样本有更高的价值。4-8月蔬菜集约化栽培被认为是取得这一结果的原因。我们的研究还表明，研究地区农民为保持农田土壤状况良好而采取的蔬菜淹水做法，导致河流和运河水中离子含量较高，成功地识别了导致环境负荷较高的耕作活动。针对这种情况提出了一些应对措施，但仍有很大的研究空间。较少

This study aims to collect basic data for building sustainable agriculture in urban peripheries of large metropolitan areas in Tropical Asia through clarifying quantitatively the actual status of environment load due to agricultural activities from the agronomic as well as social scientific points of view, and through identifying the dynamics of nitrogen/phosphorus fertilizers.In August 2002, we conducted preliminary surveys to select sample fields for this study in the basin of the Nakonchaisy covering the Districts of Nontabri, Nakonchaisy, and Suphanburi, and selected the county of Banglaen and Songpinon as the candidate areas. Also decided were four cultivation patterns to be studied ; (1)rice cultivation in paddy, (2)vegetable cultivation in polder, (3)water convolvulus cultivation in paddy and (4)water convolvulus cultivation in river.In 2003 and 2004, for the sample fields, farmers kept farming records, and sampling was commenced for monthly soil and water samples and for half-y … More early soil samples from different depth. These surveys indicated that the economic returns were high for almost all crops and cultivation patterns. It was also found that farmers adjust the quantity of fertilizers and compost according to which crop was previously grown and whether or not crops were inundated. For all crops and all crop seasons, the cost of insecticides was more than the cost of fungicides. Hired labor was employed for such farming activities as land preparation, seeding, thinning, harvesting and packing. Soil data in August and March revealed that inorganic contents were high for nearly all fields and bottom sludge of the river. In particular, August samples had higher values than March samples. The intensive management of vegetable cultivation between April and August was understood as the reason why such results were obtained. Our study also made it clear that the inundation practice in vegetable cultivation, which farmers in the study area adopted to maintain the soil condition of their fields in good conditions, resulted in the high contents of ion in the water of rivers and canals.This study succeeded to identify farming activities that result in high environment load. Some measures to counteract against such situations were proposed, but much room was left for further research. Less