分水岭
硝酸盐
氮气
环境科学
地表水
弹簧(装置)
流出物
肥料
水文学(农业)
农学
环境化学
化学
环境工程
地质学
生物
机器学习
工程类
有机化学
岩土工程
机械工程
计算机科学
作者
Daniel H. Kohl,Georgia Shearer,Barry Commoner
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:1971-12-24
卷期号:174 (4016): 1331-1334
被引量:244
标识
DOI:10.1126/science.174.4016.1331
摘要
Measurements of nitrate concentration and relative enrichment in nitrogen-15 were made on samples of the surface waters of a typical Illinois corn belt watershed and the effluent of the subterranean tiles that drain the cropped land in the region. From these measurements, we estimate that at the time of peak nitrate concentration in the spring of 1970 a minimum of 55 to 60 percent of the nitrogen found as nitrate in the surface waters of this watershed originated from fertilizer nitrogen
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