Investigation of nutrient concentration characteristics in river water at a fruit-rich watershed

通过实地调查和数值模拟对木川流域的水环境进行了评价。水果种植在这个流域非常活跃。在此基础上，建立了基于果园物质平衡的养分排放因子计算方法。此外，利用计算得到的排放因子进行的数值模拟显示，河流分支的TN浓度存在季节性变化，而河流中部的TP浓度则有较大幅度的增加。

Water environment in the Kinokawa River watershed was estimated by field surveys and numerical simulations. Fruit growing is very active in this watershed. As a result, a method to calculate nutrient emission factors using existing information based on mass balance in orchard was established. Moreover, the numerical simulations using the calculated emission factors could demonstrated seasonal changes in TN concentration in a branch of the river and huge increases in TP concentration in the middle part of the river.