Long-term water quality studies of surface waters and groundwaters in Iowa have shown increases in nitrate concentrations in surface supplies and shallow wells. In addition, the patterns of variations changed distinctly. In the past, highest nitrate values correlated with high spring flow, whereas minimum values occurred in conjunction with low flow in the fall and winter. During recent years, high nitrate values were common during periods of relatively low flow in the fall and winter. These data indicate that substantial quantities of nitrate currently may be entering surface waters from drain tiles or superficial aquifers. The application of nitrogenous fertilizers to agricultural land appears to be the primary source of nitrates in water supplies and future trends of nitrate concentrations in surface waters and groundwaters will depend on farming practices and fertilizers used. Includes 4 references, tables, figures.
| Edition : | Vol. 74 - No. 8 |
| File Size : | 1
file
, 1.2 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 4 |
| Published : | 08/01/1982 |
