青铜峡灌区氮磷运移特征试验研究

以青铜峡灌区为例,通过对输水、田间以及排水系统典型沟渠、地块的监测试验,分析了作物灌溉期氨氮、硝氮和总磷在灌区输水系统、田间系统和排水系统中的迁移变化特征.结果表明,在输水系统中,氮磷浓度大致呈递增趋势,递增的幅度与渠道基质及其中的氮磷含量有关;在田间系统,农田排水中氮磷浓度受田间施肥过程影响较大,田间氮磷流失以氮素为主,尤以硝氮较为突出;作物生长期前后,田间土壤中氮素含量在60 cm以上变化较大,下层变化较小,土壤中总磷含量变化相对较小;排水系统中,氮磷浓度沿纵向整体上是一个逐步下降趋势,从农沟口到总排口,氨氮浓度下降了25%,硝氮浓度下降了41%,总磷浓度下降了45%;受养殖污染以及部分工业、生活排污影响,干级排水沟氮浓度出现上升现象,其中以氨氮表现最为显著.

Experimental Research on Migration Characteristics of Nitrogen and Phosphorus in Qingtongxia Irrigation District

Taking the Qingtongxia irrigation district at the Yellow River upstream as an example, based on the monitor experiment material, this paper has analyzed the migration characteristics of nitrogen and phosphorus in the water conveyance system, the field system and the drainage system in the irrigations district. The results showed that, the concentrations of nitrogen and phosphorus showed increasing tendency in the water conveyance system and the increasing extent related to the channel substrate and content of nitrogen and phosphorus. In the field system, the fertilizer application process has a great influence on the concentration of nitrogen and phosphorus in farmland irrigation drainage and soil. During the crop growing period, nitrogen content in the soil above 60 cm changes greatly, total phosphorus content in the soil changes slightly correspondingly. In the drainage system, the concentrations of nitrogen and phosphorus showed decreasing tendency, from the end of farm ditch to outlet of agricultural drain, the concentration of ammonia nitrogen, nitrate nitrogen and total phosphorus in the agricultural drain decreased by 25%,41% and 45% respectively. Affected by livestock and poultry breeding pollution and so on, the concentration of nitrogen showed increasing tendency in mainstay drainage ditch.