ISSN:
1745-6584
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Geosciences
Notes:
Results of this study indicate that the nitrate and chloride concentrations in the ground water of the central Wisconsin sand plains are significantly above background, and that the main source is the irrigated agriculture in the region. Nitrate-N concentrations ranged from nil to 56 mg/1 and chloride from nil to 68 mg/1. Nitrate-N concentrations exceeded 10 ppm in 15 of 33 irrigation wells and in 2 of 3 domestic wells. Nitrate-N and chloride concentrations varied widely between adjacent wells but the CI/NO3-N ratio was much less variable. This suggests similar relative inputs of nitrogen and chloride presumably from nitrogen and potassium (potassium chloride) fertilizers.The study was conducted at three levels of intensity; a small field during one growing season, a University Experimental Farm over several years, and many local farms during part of a growing season. Differences in concentrations of nitrate-N and chloride in the surface of the ground water underlying the moderately fertilized potato field closely reflected the fertilizer and irrigation management on different parts of the field during that season. This detailed study of one field showed that solute transit times through the 16 feet (5 m) of unsaturated zone to the surface of the ground water are less than a year.Differences in concentration of nitrate-N and chloride between irrigation wells on the Experimental Farm closely reflected the irrigation and fertilizer practices on surrounding fields. Nitrate-N and chloride concentrations in ground water were lower where the adjacent land had been idle for many years and only recently cropped. However, levels were high where fertilizer and irrigation inputs.On a larger scale, the nitrate-N and chloride concentrations in area farmer irrigation wells were as different between wells on the same farm as farm as between the various farms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1745-6584.1977.tb03162.x
