The effect of agricultural water management on the water quality environment in low-lying areas

灌溉供水控制系统一直是农业用水管理工程中应用最广泛的一种。但是现在，水管理要求农村人民综合灌溉，排水和水质，以适应不断变化的生活方式，土地利用的变化和环境保护的需要。基于这一观点，本文对低洼地区的稻田灌溉、排水、水质管理和耕作管理进行了研究。青森县的津轻地区，由于稻田面积大，历史上曾采用过多种水资源利用方式。考虑了三个典型的水资源利用实例：区域自身灌溉水依赖率、抽水灌溉水和排水回用率。这些因素对分析灌溉排水水质变化、垫场出流荷载等具有重要意义 ...更多信息 干地面积、水质收支和重复使用的肥料。(1)封闭式循环灌溉系统区（2）半开放式灌溉系统区（3）开放式灌溉系统区2。3种类型稻田灌溉期内的入、出水量和水质资料分析结果表明：（1）单位面积（ha）入、出水负荷按封闭、半开放的顺序依次较小。开放式灌溉系统。在半开放式和开放式中，在水下犁和水稻种植期间输出负荷大。(2)采用闭式循环灌溉系统的稻田水质收支属于平衡型，其流出负荷与流入负荷近似相等。而开放式灌溉系统区属于污染类型。(3)日本津轻水稻区的入、出水负荷均小于其它水稻区。特别是闭式循环灌溉系统负荷小。(4)从排水到稻田的肥料再利用量由大到小依次为封闭式、半开放式和开放式灌溉系统。特别是封闭循环灌溉系统的氮肥回用量很大.在津轻地区和八郎县圩田的低洼地区，对免耕和耕作稻田的灌溉水和耕作管理进行了研究。水的需求。在水下耕作和水稻种植期间，未耕作的稻田比耕作的稻田小。少

The irrigation water supply control system was the most popular of all water management projects in agricultural areas till recently. But now-a-days, water management demands from rural peoples integrated irrigation, drainage and water quality, to correspond with the changing life style, the change in land use and the needs of environmental preservation. Based on this point of view, this paper presents a study of irrigation, drainage, water quality management and cultivation management in paddy fields in low-lying areas.Because a high percentage of the Tsugaru area, Aomori Prefecture is covered by paddy fields, it has historically utilized several types of water utilization.1. Considered are three typical examples of water utilization : the dependence rate on irrigation water from area itself, pumped irrigation water and the ratio of re-used drainage water. These factors are very important for an analysis of the quality change of irrigation-and-drainage water, the outflow load from pad … More dy areas, water quality budget and re-used fertilizer.(1) Closed circulating irrigation system area(2) semi-open irrigation system area(3) open irrigation system area2. The results of the quantity-and-quality data flowing in or out of 3 types of paddy areas during the irrigation periods can be indicated as a fallows :(1) The inflow and outflow load per unit area(ha) is small in the order of closed, semi-open. and open types irrigation system. In semi-open, and open types, the output load is large during the under-water ploughing and rice-planting periods.(2) The water quality budget of paddy area using the closed circulating irrigation system belong to the equilibrium type, where the outflow load is approximately equal to the inflow load. But open irrigation system area belong to the pollution type.(3) The inflow and outflow loads of Tsugaru paddy areas are smaller than those of other paddy areas in Japan. Especially, the loads of closed circulating irrigation system are small.(4) Re-used fertilizer from drainage water to paddy fields is large in the order of closed, semi-open, and open types irrigation system. Particularly, re-used nitrogenous fertilizer of closed circulating irrigation system is very large.3. Irrigation water and cultivation management for non-tilled and tilled paddy fields are examined in low-lying areas of the Tsugaru area and Hachiro-gata polder. Water requirement of. non-tilled paddy fields are smaller than tilled paddy fields during the under-water ploughing and rice-planting periods. Less