Systems approach to nitrogen modeling in the Chesapeake Bay: Advancing production chain analysis under future changes

Area of Science:

• Environmental Science
• Agricultural Science
• Systems Ecology

Background:

• Agricultural runoff contributes over 40% of Chesapeake Bay's nitrogen pollution.
• Field-level management practices are insufficient for watershed restoration.
• A systems-level approach is needed to manage nitrogen flows across the food production chain.

Purpose of the Study:

• To investigate the impact of future agricultural changes and management on nitrogen loss in the Chesapeake Bay Watershed.
• To analyze nitrogen flows through seven stages of the food production chain using a systems approach.
• To identify key leverage points for nitrogen management under future scenarios.

Main Methods:

• Developed simulated scenarios for agricultural intensification, efficiency improvements, and combined strategies.
• Utilized a systems approach production chain analysis to track nitrogen flows.
• Incorporated climate-driven changes in crop yields and animal production growth.

Main Results:

• Total nitrogen loss is influenced by a combination of factors, including crop/animal production amounts, fertilizer rates, live animal weight gain, and feed conversion ratios.
• Live animal weight gain and feed conversion ratio were quantified as significant contributors to total nitrogen loss.
• The influence of these factors evolves under future climate-impacted and production conditions.

Conclusions:

• Systems-level perspectives across interconnected food production chains are vital for identifying effective nitrogen management strategies.
• This approach provides pathways to meet watershed quality objectives amidst agricultural intensification and climate change.
• Identifying consequential leverage points requires understanding the interplay of various factors in nitrogen loss.