Characteristics of Decomposition of Nitrogen and Carbon in the Sediments in Agricultural Drainage Canals
Characteristics of Decomposition of Nitrogen and Carbon in the Sediments in Agricultural Drainage Canals
复制标题
DOI：
10.2965/jwet.2014.151
复制
发表时间：
2014
影响因子：
--
通讯作者：
Tomohisa Nagai;T. Hama;Sho Sugiyama;Daichi Iwasaki;Fuminori Igarashi;S. Kawashima
中科院分区：
文献类型：
--
作者：
Tomohisa Nagai;T. Hama;Sho Sugiyama;Daichi Iwasaki;Fuminori Igarashi;S. Kawashima
在农业地区实施了许多水质保护措施，以减少污染物负荷。然而，控制排放的排水会增加这些地区排水渠中悬浮物的沉降。沉积物中氮(N)和碳(C)浓度较高，可能释放N和C，降低了保护措施的效果。在本研究中，我们明确了排水渠沉积物中N和C的特征。我们对琵琶湖周边水田区进行了调查，测定了沉积物中的氮、碳含量。我们还对两个不同水田区取样的沉积物进行了孵育实验。分析了孵育期间沉积物和上覆水体中N、C组分的变化。因此，孵育沉积物上覆水体的总氮和总有机碳浓度分别约为研究点测量的排水浓度的2倍和3倍。总氮通量为33.0 ~ 41.1 mg /m 2 /d，总有机碳通量为25.3 ~ 48.4 mg /m 2 /d。结果表明，沉积物中有足够的氮和碳来确定排水水质。
Many water quality conservation measures have been implemented in agricultural areas to reduce pollutant loading. However, controlling discharged drainage water enhances sedimentation of suspended solids in drainage canals in those areas. The sediment, which has high concentrations of nitrogen (N) and carbon (C), may release N and C and lower the effect of the conservation measures. In this study, we clarified the characteristics of N and C in the sediment in drainage canals. We have investigated paddy field districts around Lake Biwa and measured N and C contents in the sediment. We also conducted incubation experiment of the sediments sampled in two different paddy field districts. Changes in N and C fractions in the sediments and in the overlying water during the incubation period were analyzed. As a result, concentrations of total N and total organic C in the overlying water of the incubated sediment were respectively about two and three times those of drainage water measured at the study points. Total N flux was 33.0 – 41.1 mgN/m 2 /day and total organic C flux was 25.3 – 48.4 mgC/m 2 /day. It was indicated that the sediments had enough N and C for determining the water quality of drainage water.