Non-point pollutant reduction in a paddy-field watershed using a circular irrigation system
Non-point pollutant reduction in a paddy-field watershed using a circular irrigation system
复制标题
DOI：
10.1016/s0043-1354(97)00117-6
复制
发表时间：
1997-11
期刊：
影响因子：
12.8
通讯作者：
I. Takeda;A. Fukushima;R. Tanaka
中科院分区：
文献类型：
--
作者：
I. Takeda;A. Fukushima;R. Tanaka
以一个实施循环灌溉的稻田小流域为研究对象，分析了该流域3年来氮、磷污染物的通量变化。污染物的年净流出负荷，即流出负荷减去流入负荷，如下：第一、第二和第三年的总氮负荷分别为-5.46、+ 58.7和-4.20 kg ha− 1 yr −1，总磷负荷分别为-2.87、+ 1.13和-1.70 kg ha− 1 yr −1。第二年的正净流出负荷受到相当大的降水量的强烈影响。结果表明，在正常水文年，研究流域净化了氮磷化合物。尽管没有显着的浓度下降的良好的净化性能的原因是，大量的水，通常超过1000毫米，除了降水，流经流域内的稻田灌溉。研究流域似乎有理想的污染物去除功能，沉积是更有效的比在河流中的冲洗，和保留时间是足够的净化机制在稻田。虽然循环灌溉系统最初的设计目的不是为了去除污染物，而是为了供应稻田灌溉用水，但它可以减少非点源污染物。
The pollutant fluxes of nitrogen and phosphorus were elucidated for 3 years in a paddy-field watershed where a circular irrigation system was implemented. The annual net outflow loads of pollutants, i.e. the outflow load minus the inflow load, were as follows: the total nitrogen loads for the first, second and third year were − 5.46, + 58.7 and − 4.20 kg ha−1yr−1, respectively, and the total phosphorus loads were − 2.87, + 1.13 and − 1.70 kg ha−1yr−1, respectively. The positive net outflow loads for the second year were strongly affected by a considerably large amount of precipitation. It is concluded that the study watershed purified nitrogen and phosphorus compounds during normal hydrological years. The reason for the good purification performance in spite of no significant concentration decrease was that a large amount of water, usually more than 1000 mm excepting precipitation, flowed within the watershed by paddy-field irrigation. The study watershed seemed to have the desirable function of pollutant removal, with the deposition being more effective than the flushing in the river, and the retention time being sufficient for the purification mechanisms in paddy fields. Although the circular irrigation system was originally designed not for the purpose of pollutant removal but to supply water for paddy-field irrigation, it can contribute to reducing non-point pollutants.