Nitrogen Loss Estimation Worksheet (NLEW): an agricultural nitrogen loading reduction tracking tool

Area of Science:

• Environmental Science
• Agricultural Science
• Water Resource Management

Background:

• The Neuse River Basin faces significant nitrogen (N) pollution, with agriculture contributing over 50% of the total load.
• Regulatory efforts since 1998 mandate a 30% N loading reduction into the Neuse Estuary from all pollution sources.
• Nonpoint source pollution from agriculture presents challenges due to its diffuse nature and variability.

Purpose of the Study:

• To introduce and evaluate the Nitrogen Loss Estimation Worksheet (NLEW) as an agricultural N accounting tool.
• To provide flexibility for the agricultural community in implementing and tracking best management practices (BMPs) for N reduction.
• To support county-level strategies for achieving targeted N load reductions.

Main Methods:

• Development of the Nitrogen Loss Estimation Worksheet (NLEW) using a modified N-balance equation.
• NLEW tracks N inputs and reductions from nutrient management and other BMPs.
• The tool operates at both field- and county-level scales for comprehensive N accounting.

Main Results:

• NLEW facilitates the tracking of N reductions achieved through the implementation of various BMPs.
• The tool has been utilized by counties to devise N reduction strategies.
• It aids in assessing the effectiveness of agricultural management practices in meeting regulatory targets.

Conclusions:

• The NLEW provides a valuable framework for agricultural N management and accounting.
• It offers flexibility and supports targeted N reduction efforts in the Neuse River Basin.
• Effective implementation of NLEW can contribute to achieving water quality objectives and protecting aquatic ecosystems.