A study on nitrate contamination of ground water sources in areas of protected vegetables-growing fields ―a case study in huimin county, shandong province | 北方设施蔬菜种植区地下水硝酸盐来源分析――以山东省惠民县为例

Chinese. 【目的】以华北平原典型集约化设施蔬菜种植区山东省惠民县为研究对象,分析浅层地下水硝酸盐的含量状况并追溯其来源。【方法】多点采集设施蔬菜种植区土壤、肥料及地下水样品,利用稳定性同位素技术识别地下水氮污染的可能来源。【结果】结果表明,蔬菜大棚区浅层地下水硝态氮含量为25.3―279.6 mg?L-,平均为121.6 mg?L-,87%的样品硝态氮含量超过50 mg?L-1;较集中分布在50―70 mg?L-1和170―190 mg?L-1区间,含量最高的点位超标高达27倍;5种蔬菜大棚地下水硝态氮的含量依次为：黄瓜＞芹菜-辣椒和辣椒＞芹菜-黄瓜和芹菜-番茄。研究区域内土壤的δ15 N值在1.96‰―7.38‰之间,化肥(尿素、复混肥等)在0.2‰―0.6‰之间,动 物粪便(农家肥、厩肥)在7.3‰―16.87‰之间;地下水样的δ15 N值变化在-0.01‰―15.91‰之间,平均为 6.75‰±3.15‰,随NO3--N含量减少地下水δ15N值未呈现增加趋势,该研究区域内地下水反硝化作用较弱。【结论】蔬菜棚区内浅层地下水硝态氮污染十分严重,受人为因素干扰很大;硝酸盐主要来源为土壤有机氮,其次为动物粪便。

English. 【Objective】 Huimin County in Shandong Province is a typical intensive vegetable planting area in North China Plain. The concentration of nitrate in shallow ground water in this county was analyzed and potential source of nitrate was tracked.【Method】 Multi-point collection of samples of soil, fertilizer and underground water in the vegetable planting area was made; then stable isotope technology was used to track the potential source of nitrite in groundwater. 【Result】 The result showed that the concentration of nitrate ranged from 25.3 to 279.6 mg?L-, with an average of 121.6 mg?L-1 which was about 600 times as much as that in deep well water in field. The highest concentration of nitrate in ground water was in cucumber patch, followed by celery-chili patch, chili patch, celery-cucumber patch and celery-tomato patch. In the study areas, the concentration range of δ15 N in the soil was from 1.96‰ to 7.38‰ and the concentration of chemical fertilizer (such as urea and compound fertilizer) and dung (such as farmyard manure and stable manure) ranged from 0.2‰ to 0.6‰ and from 7.3‰ to 16.87‰, respectively. The δ15 N value of ground water sample ranged from -0.01‰ to 15.91‰ with an average of 6.75‰ ±3.15‰. The value of δ15 N in ground water was not accordingly increased with the decrease of concentration of NO3-N. The results also showed that the denitrification of ground water was relatively weak in the study areas.【Conclusion】 The nitrite contamination of shallow ground water in vegetable greenhouses is extremely serious, and it is seriously influenced by humanity. The main source of nitrate is soil organic nitrogen, and the minor source is animal dung.