Prediction of the fate of agrochemicals based on model parameter estimation and GIS

一个数学模型已开发用于描述农化学品运行在paddy field to river并应用于Oirase River Basin （主河长度70 km，总盆地区域844 km，D12 ye D1， Aomori Prefecture）。1995年和1996年收集的农用化学品集中测量数据;河底的整个区域被分成正方形网格（5公里x5公里），每个网格的陆地覆盖被归类为山区和森林、帕迪菲尔德、干燥农场和城镇。该喷洒时间表和农用化学品的用量已根据1995年和1996年的商业农用化学品的营销信息和农用化学品的日历进行了估计。十一种化学化合物被选定为分析的目标。土壤在每个化合物中的吸收性和生物降解性被估计为物理化学和生物特征，从河流盆地的八个观测点收集了水文数据，并通过蒂森的方法分配到每个网格。这表明，蒸发和转运的数量是由Brutsaert和Stricker-Five Estimation方法中最好的估计。这也表明，雪融化的数量是根据温度指数法准确估计的。一个部门模型，以模拟最少六个部门所需的农用化学品行为，命名;河水相，河底固体相，帕迪场水相，帕迪场底部固体相，土壤A相和土壤B相。模拟结果显示，农化学化合物的运行行为在喷雾期和每个化学品的数量上受到了极大的影响，以及雨水期。并控制从Paddy Fields释放的水。

A mathematical model was developed to describe the agrochemicals runoff used in paddy fields into rivers and applied to the Oirase River Basin (main river length 70km, total basin area 844kmィイD12ィエD1, Aomori Prefecture). The data of concentration measurement of agrochemicals was collected for the year 1995 and 1996.The whole area of the river basin was divided into square meshes (5km x 5km) and the land coverage of each mesh was categorized as mountain and forest, paddy field, dry farm field, and town. The spraying schedule and the dosage of agrochemicals was estimated for 1995 and 1996 based on the marketing information of the commercial agrochemicals and the calendar for farmers. Eleven chemical compounds were selected as the target of analysis. The adsorbability and biodegradability in the soil was estimated by the physical-chemical and biological characteristics of each compound.Hydrometeorological data was collected from eight observation points in the river basin and allocated to each mesh by Tiessen's method. It was shown that the amount of evaporation and transpiration is best estimated by the method of Brutsaert and Strickerand among five estimation methods. It is also shown that the amount of snowmelt is precisely estimated by the temperature index method. The compartment model to simulate the behavior of agrochemicals needed at least six compartments, namely; river water phase, river bottom solid phase, paddy field water phase, paddy field bottom solid phase, soil-A phase and soil-B phase.Simulation results showed that the runoff behavior of the agrochemical compounds was largely affected by the spraying period and the amount of each chemicals, the period of rainfall, and the control of water discharge from paddy fields.