Chaparral conversion and streamflow: Nitrate increase is balanced mainly by a decrease in bicarbonate

Publisher Website
Google Scholar
Abstract
Converting Arizona chaparral watersheds to grass by controlling the brush with herbicides increases water yield as subsurface runoff to streams. The increased stream discharge is accompanied by several hundredfold increases in the nitrate concentration of the stream water. Nitrate concentrations remained 46–69 fold above normal for 11 years or more. Nitrate ion concentration increases were balanced mainly by bicarbonate ion concentration decreases, with little change in the concentration of other anions or cations. One mechanism suggested to explain the decrease in bicarbonate that balances the increase in nitrate is the reaction of H+ NO3− with HCO3− to give carbon dioxide and water.