Minimizing The Impacts Of Agriculture On Water Resources

By Pongpun Juntakut, PhD candidate, Civil Engineering, University of Nebraska, Lincoln, and 2017 Next Generation Delegate

Due to increasing population growth and food demand around the world, global food crises are increasingly likely to happen. Thus, food security can be a powerful tool to mitigate violence and conflict, and to promote national security. The Chicago Council on Global Affairs’ Global Food Security Symposium presented these ideas in a new perspective to me, and prompted me to rethink the role of the military in achieving national security by increasing food security. 

While the Symposium focused primarily on global food security, it’s important to remember that agriculture—and therefore food security—is inexorably linked to water security. To ensure sustainable development of food systems, we must also conserve natural resources and minimize the impact of intensive agriculture on fresh water. Groundwater is a major resource for agriculture and human consumption worldwide, especially in the United States, but has been impacted due to application of nitrogen fertilizers in agricultural areas. The US Geological Survey (USGS) reported in 2016 that more than one million private domestic wells during 2012-2013 are located in risk areas where the nitrogen concentration is above the standard limit of 10 mg of nitrogen per liter of water, as regulated by the US Environmental Protection Agency (EPA). Drinking nitrate-contaminated water can cause various health problems, including a temporary blood disorder in infants called blue baby syndrome, as well as cancers and other chronic conditions. Most nitrogen compounds in commercial fertilizers and manure can be converted to nitrate. Nitrate is highly soluble in water and can easily be transported through soil to groundwater. Thus, controlling and monitoring nitrogen leaching from agricultural areas is important for planning and controlling nitrate occurrence in groundwater.

Nebraska, for example, has a large number of wells dug where the nitrate concentrations in groundwater are above the drinking water standard set by the EPA. A major cause of nitrate concentration in wells is due to extensive fertilizer application. Currently, more application of nutrients, pesticides, and irrigation water has increased crop yield. The high nitrogen contamination in groundwater is also causing uranium in the aquifer to oxidize and become more soluble. As a result, Nebraska’s Natural Resources Districts (NRDs) started a groundwater quality management program (GWQMP) in 1988 to monitor the nitrate occurrence with four different phases. Phase I, II, III and IV have been classified based on nitrate concentrations of ≤7.5, 7.6-15, ≥15 mg nitrogen per liter of water, and not declining at acceptable rate of nitrate-to-nitrogen levels, respectively. Within the areas of Phase II and III, the timing and application rates of nitrogen fertilizer on irrigated agriculture are regulated. In Nebraska, nitrogen application is not allowed before the first of March. Additionally, the state is trying to control over-application by taking credits for organic matter conversion to nitrogen, manure, and other organic manure additions and by irrigation with nitrogen-contaminated groundwater. Furthermore, it’s recommended that farmers apply their fertilizer in multiple applications, with no more than half their allotted nitrogen applied prior to planting.

And this isn’t only an issue in the United States. In the developing world—in countries like Thailand, where I’m from—treating contaminated groundwater is expensive, sometimes prohibitively so. In such situations, the need to prevent nitrogen from leaching into the groundwater in the first place is more important than ever. Best practices, like preventing farmers from over-applying nitrogen to their fields, and encouraging farmers to use appropriate fertilizer management and irrigation practices, are some of the best ways to prevent groundwater from becoming contaminated. These are important steps to take to preserve quality drinking water, and by extension, water and food security. As described, in order to produce sustainable food systems, we must consider the impact of intensive agriculture on water resources. I strongly believe that experience and knowledge gained from my time at the University of Nebraska, and at the 2017 Global Food Security Symposium, will enable me to tackle these lessons learned home to Thailand, and apply them to any developing country in need.