A TALE OF TWO BREADBASKETS: A COMPARISON OF AGRICULTURAL PRACTICES AND NITROGEN POLLUTION IN THE DES MOINES (IOWA) AND SHAYING (CHINA) RIVER BASINS

The Midwestern United States is the “breadbasket” region of the country, and its agricultural conditions are typified in the Des Moines River basin of Iowa. The Huai River basin of China is also a breadbasket region of the country: the farmland in this area produces 16.5% of China’s grain from 3% of China’s total land area. The impacts of intense Midwestern monolithic agriculture on water quality have been documented for decades, especially in regards to nitrate pollution.

Besides the health risk of nitrate-polluted water, there are also highly damaging ecological consequences of nitrate pollution in the United States, one example of which is the growing dead zone in the Gulf of Mexico. Pollution due to agriculture has also been heavily researched in many areas of China, however, there are few studies of the highly agricultural Shaying River watershed, a tributary of the Huai River basin, and extensive spatial and temporal data on nitrogen pollution in the area is lacking. This paper examines data collected in the Shaying River watershed in the fall of 2011 and compares agricultural production and water quality in these two intensely agricultural watersheds.

The groundwater samples for this project were collected from domestic (n=15) and irrigation wells (n=117) in the Shaying River watershed, and surface water samples (n=19) from the Shaying River and its tributaries. Though the use of nitrogenous fertilizer use was reported to be much higher in the Shaying River watershed than in the Des Moines River basin, the mean surface water nitrate content in the Shaying River watershed was 2.88 mg/L, compared to 6.37 mg/L (n=1390) in the Des Moines River watershed. Groundwater nitrate results were highly variable, ranging from 0-52 mg/L, with a mean concentration of 4.2 mg/L, which is similar to the mean value of 6.5 mg/L (n=6258) of the Des Moines River watershed reported in the Iowa DNR database.