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Project study on Material Cycle in Paddy Field Biotope

稻田生境物质循环课题研究

基本信息

批准号：
13306025
负责人：
KATO Makoto
金额：
$ 30.45万
依托单位：
Tokyo University Agriculture And Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

In order to preserve healthy paddy field ecosystem, it is important to estimate diffusive flux of chemical substance in irrigation water such as pesticide and fertilizer that flows into paddy field. The transport phenomenon of dissolved pesticide and fertilizer in irrigation water was characterized as diffusive and dynamic phase in the paddy field.The behavior of irrigation water near by the inlet of the modeled paddy field was observed such that the irrigated water flowed into paddy field with a whirl-motion with increasing its size as it move into the paddy field. Water flow formed the two zones of high speed flow and very slow speed flow. The former the solute in the irrigation water moves by the advection the latter by the diffusion. It was indicated that it had to be evaluated by appropriate places and appropriate quantities of the samplings, etc., when diffusive conditions of the pesticide in paddy field, etc. were investigated.Dr.Watanabe studied pesticide fate and transport in … More paddy field and its application for the good agricultural practices such as irrigation and drainage controls for the paddy rice production. As the result, Automatic irrigation system with high drainage gate that can store the paddy water and prevent runoff during the significant rainfall event can be recommended as the best management practice. Also, usual flow through irrigation or continuous irrigation-drainage scheme having significant amount of pesticide 'runoff from paddy field is not recommended for preserving aquatic ecosystem and paddy field biotope. Simulation model of PCPE-1 was intended to use in this case however the result underestimated the observation. Hence. this system has the necessity of the improvement.Dr.Okazaki measured Cd balance of the Honmachi university experimental paddy fleld Considering adsorbed cadmium in the rice was 6mg/ha/year, etc., the inflow of Cd from the Honmachi paddy field estimated to be 5mg/ha/year, and its ninoff with 10mg/ha/year. This indicated that the attention was needed for the Cd Japanese regulation.Dr.Toyoda carried out the field investigation of the feed rice plant under the condition of fertilization and non-fertilization of the nitrogen fertilizer in the Honmachi university experimental paddy field. As the result of estimated nitrogen budget, the quantity of 248kgN/ha in the fertilization treatment and 118kgN/ha in the non-fertilization treatment was stored into the ripe plant from paddy field soil.Dr.Hrasawa compared with direct seeding and transplantation cultivation practice, and examined for the dry weight production and nitrogen accumulation.The result showed that there were more biomass in direct seeding, because the leaf received a great amount of solar radiation d***ing the growing period, and that the environmental condition of other influencing organism during the growing period for direct seeding practice is some what different from that of the transplantation cultivation.Dr.Fukushima showed that the considerable deference in plant community in terraced paddy field and in Yachida. Observed plant community had 348 kinds in the terraced paddy field, on the other hand, there were 309 types in Yachida. There was the hydorphyte conmmunity in Yachida to locate valley part in geographical feature. However, in order to locate the highland using rain water, the kind of plant community in terraced paddy field was different. It is considered that the different ecology was observed depending on the landform. Less

为了保护健康的稻田生态系统，估算农药、化肥等化学物质进入稻田后的扩散通量具有重要意义。模拟结果表明，溶解态农药和化肥在稻田中的迁移过程为扩散和动态过程，在模拟稻田进水口附近，灌溉水进入稻田的过程为往复运动，其体积随着进入稻田而增大。水流形成了高速流和极低速流两个区域。前者是灌溉水中溶质的平流迁移，后者是扩散迁移。指出必须通过适当的地点和适当的取样数量等进行评价，渡边博士研究了农药在稻田中的归趋和迁移， ...更多信息稻田及其良好农业规范的应用，如水稻生产的灌溉和排水控制。因此，高排水闸自动灌溉系统，可以存储水稻水，防止径流在重大降雨事件可以推荐为最佳的管理实践。此外，通常的流水灌溉或连续灌溉排水方案有大量的农药径流从稻田是不推荐的保护水生生态系统和稻田生物群落。PCPE-1的模拟模型原本打算用于这种情况，但结果低估了观察结果。因此。冈崎博士测量了本町大学实验稻田的镉平衡，考虑到水稻中吸附的镉为6 mg/ha/年等，本町稻田Cd的流入量为5 mg/ha/年，其Ninoff为10 mg/ha/年。丰田博士在本町大学实验稻田中，对施氮和不施氮条件下的饲料稻进行了田间调查。根据氮素收支估算结果，施肥处理和不施肥处理分别有248 kgN/ha和118 kgN/ha从稻田土壤中储存到成熟植株中。平泽博士将直播和移栽栽培进行了比较，并对干物质生产和氮素积累进行了考察。结果表明，直播有更多的生物量，福岛博士指出，水稻直播栽培在水稻生长期内，由于叶片接受了大量的太阳辐射，而其他影响生物生长的环境条件与移栽栽培有所不同，因此，梯田和八田的植物群落有很大的差异。在梯田中观察到的植物群落有348种，而在八田中有309种。在地理特征上，八知田位于山谷部分，有水生植物群落。然而，为了利用雨水定位高地，梯田的植物群落类型是不同的。据认为，根据地形观察到不同的生态。少