Clean water has global scale benefits, both for human consumption directly and indirectly through the consumption of fish and other food sources in water. Phosphorus, Nitrogen and sediment runoff in mass amounts lead to poor water quality in watersheds, and agricultural production is a significant source of these pollutants. Phosphorus and Nitrogen contribute to algae blooms, and other water-based organisms that deplete oxygen in the water, and thereby limit the ability of water-based species to flourish. Sediment accumulation destroys the base for the growth at the bottom of the food chain and can create problems procuring potable water. Historically, traditional farming methods used these chemicals to enhance yield. Sediment build-up is often the result of the nature of the way water flows into and through watersheds, some caused by human manipulation of the surrounding topography, other sediment movement caused by nature itself.

An effort is underway to restore clean water to the Chesapeake Bay by limiting the amount of Phosphorus, Nitrogen and sediments flowing into the bay from its tributaries through the Chesapeake Total Maximum Daily Load (TMDL) program. The intent is to clean-up the water by limiting chemicals like Phosphorus and Nitrogen, along with other sediment that might flow into the James River. However, it has been found that agricultural yields are one of the few issues in which nutrient pollution is not decreasing (Zaring 1996). The University of Richmond has restored the campus stream, Little Westham Creek, in order to decrease the city’s TMDL amounts. There is also a campus garden that has historically been organic and intends to stay this way upon reopening in 2020. Implementing organic farming techniques and methods to farms in Richmond can lead to reduced nutrient runoff and limited pesticide use, which in turn will improve water quality. This paper focuses on the control of Phosphorus and Nitrogen and does not directly address sediment. There are multiple ways to think about reducing levels of the chemicals and sediment. Through a meta-analysis of multiple case studies, this paper examines the effect organic farming methods have on nutrient retention in soils and how this affects agricultural yields. Overall, the results have proven that organic soil does in fact retain nutrients better than synthetic soil, but there is also higher risk of eutrophication in waterways, if organic approaches are not carried out mindfully, or managed properly. Organic farming practices are important for both human and environmental health. “The overall management aim is to reduce off-farm inputs and minimize waste and environmental degradation, whilst encouraging resilience to disturbances such as disease outbreaks and adverse weather” (Ryan et al. 2014). Tillage, vermicompost, and soil fertility are the three most prevalent indicators of higher organic yields and higher Nitrogen and Phosphorus levels. There is no correlation between study date and yield/nutrient outcome. Organic yields can neither be proven or disproven to be equivalent or better than conventional yields.

Paper prepared for the Environmental Studies Senior Seminar/Geography Capstone.

Faculty Advisor: Dr. Todd Lookingbill

Document Type

Unpublished Paper - Campus Only

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