Andrew’s Blog
Effects of CAFOs on Water Quality
October 10, 2021
What’s at stake?
Concentrated Animal Feeding Operations (CAFOs) and fertilizer application to row crops has been related to increased pollution within waterways. In this study, four watersheds in Eastern Iowa were measured from 1988-2004 for nutrient concentrations. These four watersheds contributed to around 10% of annual nitrate flux into the Gulf of Mexico. The relative size and spatial distribution of row crops is directly correlated with nitrate concentrations in streams. Inputs of Nitrogen include fertilizer applied to crops, nitrogen fixation from soybeans and manure. Iowa is the ideal location for this study since it is one of the most, if not the most agricultural state in the United States. While there are other factors that might affect water quality such as the type of landscape or natural disasters that may occur around CAFOs, it is significant to view the impact on crop spatial distribution, as this can be changed.
Why care?
This post focuses on a key issue in the United States, animal agriculture and the effects on water quality. It is important to understand this relationship so we can better adapt to increasing human population and an increase in meat production/demand. Understanding the cause and effect connection may lead to increased awareness about our food sources and the potential consequences on stream water pollution.
The “Beef”
It has been found that states with high concentrations of CAFOs experience on average 20 to 30 serious water quality problems per year as a result of manure management problems (EPA, 2001). Looking at CAFOs from a general perspective, they may work in the sense that they produce a majority of food for America, but the overarching negatives, especially dealing with water quality may prove to be the downfall for these facilities. Learning about the essential impacts that CAFOs produce will help to better educate future generations. While current populations are rising, the demand for food has become increasingly widespread. While CAFOs are an efficient way of mass production, they create a disbalance in ecosystems and impact water quality for neighboring water sources.
This study was conducted at four sites in Eastern Iowa, where major CAFOs are implemented. Methods of raising food in order to feed the livestock is done with row cropping, which is usually located adjacent to the facility. Through uses of pesticides and fertilizers on crops, nitrogen fixation from certain crops and waste from the animals, this affects the water quality of streams. According to the study, as animal unit density increases and row crop density increases, the nitrate concentration increases as well. Manure was proven not to be a major factor for influencing water quality, it is seen that the more animal density, the higher the amounts of waste leading to decreased stream quality. Through certain statistical analyses, data shows that as time has progressed, nitrate concentrations have increased dramatically. To add, row crop density and nitrate levels have been positively correlated, while row crop density with other nutrients have been negatively correlated. Furthermore, there is a direct correlation with the number of CAFOs and nitrate concentrations, with a PCC value of 0.627 and a P-value of 0.007. According to multiple statistical tests, nitrate and row crop area are moderately correlated, while all other nutrients are negatively correlated. Moreover, conclusions can be derived using regression analysis and the R^2 value. Using the equation: Nitrate Concentration= 2.39 + 7.65 (Animal Unit Density) + 7.01 (Row Crop Density) R^2= 84.8%. This can be directly linked to modern farming practices (CAFOs) since river nitrate concentration is around 0.1 times the watershed’s row crop percentage.
While the data is proven to be evident, this only takes into account four sites in Eastern Iowa. The overall results state that increased animal densities and high row crop densities are associated with increased nitrate levels in the accompanying watershed, proving that this issue of poor water quality will become rampant in areas with lots of CAFOs.
