辽河流域典型种植区地下水硝态氮含量特征分析

Nitrate Nitrogen Concentration Characteristics in Underground Water of Typical Planting Areas in Liao River Basin

以辽河流域典型种植区为研究区域，对其地下水硝态氮含量进行分析，为合理施肥及有效防控种植区地下水硝态氮含量超标提供理论依据。结果表明，辽河流域不同典型种植区地下水硝态氮含量差异明显，具体表现为花卉种植区（37.4 mg/L）〉玉米种植区（22.3 mg/L）〉蔬菜种植区（21.9 mg/L）＆gt;水稻种植区（19.2 mg/L），各典型种植区地下水硝态氮含量除水稻种植区外都超标，但水稻种植区地下水硝态氮含量变异系数较大，有超标的风险；地下水硝态氮含量超标率差异也较明显，其中玉米种植区超标率为12.5%~87.5%，水稻种植区为9.4%~75.5%，蔬菜种植区为17.9%~58.9%，花卉种植区为21.4%~96.0%。另外，对于同一井深，不同种植区地下水硝态氮含量总体均表现为雨季前＆gt;雨季后。

The contents of nitrate nitrogen（ NO3--N） in underground water from typical planting areas in Liao river basin were analyzed,so as to provide theoretical basis for rational fertilization and effectively provent the NO3--N content from exceeding standard. The results showed that difference of the contents of NO3--N in groundwater from different typical planting areas was significent. The highest content of NO3--N in underground water was 37. 4 mg/L from flower-growing region,then 22. 3 mg/L from maize-growing region,21. 9 mg/L from vegetable-growing region,and the lowest content of NO3--N in underground water was 19. 2 mg/L from rice-growing region. Except rice-growing region,the contents of NO3--N in under-groundwater of the samples in all planting areas were exceeding standard limit; potential health risk still existed in rice-growing region. Accordingly 12. 5%—87. 5%,9. 4%—75. 5%,17. 9%—58. 9% and 21. 4%—96. 0% of the samples were exceeding standard limit in maize growing region, rice-growing region,vegetable-growing region and flower-growing region. The contents of NO3--N in under-groundwater before the rainy season was higher than that of NO3--N in under-groundwater after the rainy season at the same depth of the well.