Exploring Intensive Agriculture and Organic Fertilizer Management in the US: Implications for Nutrient Pollution Prevention

Intensified food production on large farms across the world has led to discussions on how to facilitate sustainable policies and practices to reduce nutrient pollution. In Chapter 1, I evaluated the co-variability of agricultural intensification, environmental degradation, and socio-economic indicators throughout the US to explore the potential evidence for the existence of sustainable intensification of agriculture in the US. I identified distinct agro-social-eco regions in the US that provide background for future regional studies of (sustainable intensification) SI in the US and beyond. I observed regions of moderate agricultural intensity and lower environmental degradation within the Great Plains, and regions of high agricultural intensity and higher environmental degradation throughout portions of the Midwest. Insights gained from this study can provide roadmaps for improved sustainable agricultural intensification within the US. In Chapter 2, the study summarized state regulations controlling a key nutrient input - the land application of biosolids from human wastewater treatment and manures from regulated animal feeding operations. Results indicate high variability of both manure and biosolids regulations among the states and stark differences in the regulation of land application of biosolids versus manures. This work can be used to identify opportunities for the strengthening of regulatory frameworks for managing these resources with minimal risk to the environment. In Chapter 3, I combined aspects of the previous chapters to understand the potential impact of specific CAFO land application regulations on nutrient pollution and assess if stricter regulations related to better environmental outcomes. I compared TN AND TP accumulated yields in surface waters across US States with state specific CAFO land application regulations across US Policy scenario tests revealed that more restrictions were associated with higher nutrient levels, indicating reactive policy making and delayed nonpoint source pollution responses. Overall, I found that fostering adaptive capacity and management within delineated agro-social-eco regions will likely facilitate sustainable food systems in the US.