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排灌系统底泥特征是反映土地利用变化生态影响的重要途径,为此对内蒙古河套灌区永济灌域灌排系统底泥有机碳和总氮含量进行了系统研究。结果表明:灌域内永济给水干渠(简称永济干渠)与四号、五号排水干沟(简称四排干、五排干)表层底泥的有机质(OM)及总氮(TN)含量特征分布有所差异。其中均以五排干上游底泥中含量最高,OM与TN平均值分别为3.60%和0.35%,超出河套地区平均值的4.82倍和2.94倍;其底泥有机指数也达到重污染水平,富营养化程度较高;永济干渠底泥OM与TN含量最低,分别为1.41%和0.03%,属于清洁贫营养化级别;四排干底泥OM与TN含量介于五排干和永济干渠之间,其上游较为清洁,基本接近平均值,C/N平均在17左右。排干底泥有机质与总氮含量之间显著相关,y(TN)=0.141x(OM)-0.180(r=0.978;P<0.001)。
The sediment characteristics of irrigation and drainage system is an important way to reflect the ecological impact of land use change. Therefore, the organic carbon and total nitrogen content of sediment in Yongji irrigation area in Hetao irrigation area of Hetao irrigation area are systematically studied. The results showed that the organic matter (OM) and total nitrogen (TN) content of surface sediments of Yongji water supply canal (Yongji trunk canal) and No.4 and No.5 drainage ditches (shortened four rows and five rows of drainage) Distribution is different. The contents of OM and TN were 3.60% and 0.35%, respectively, which were 4.82 times and 2.94 times higher than that of Hetao area. The organic index of sediment also reached the level of heavy pollution, The degree of eutrophication is higher. The content of OM and TN in bottom sediments of Yongji trunk channel is the lowest, which is 1.41% and 0.03%, respectively. Between the upstream, the cleaner, almost close to the average, C / N average of 17 or so. There was a significant correlation between organic matter and total nitrogen content in drained sediments, y (TN) = 0.141x (OM) -0.180 (r = 0.978; P <0.001).