Updated method to incorporate soil nutrient heterogeneity caused by urine excretion into a process-based simulation...

Area of Science:

• Agricultural Science
• Environmental Modeling
• Soil Science

Background:

• Process-based simulation models struggle with nutrient cycling in grazed pastures.
• Livestock urine creates extreme soil nitrogen heterogeneity, impacting production and environmental loss estimations.
• Averaging heterogeneous soil data overestimates pasture growth and underestimates nitrogen leaching and greenhouse gas emissions.

Purpose of the Study:

• To develop an efficient method for modeling nutrient heterogeneity in grazed pastures.
• To preserve key aspects of soil nutrient heterogeneity for accurate environmental loss simulations.
• To enable computationally tractable simulations of complex pasture systems.

Main Methods:

• An updated method was developed to model non-uniform nutrient applications in soil simulation models.
• The approach captures significant implications of non-uniformity on soil and plant processes.
• The method ensures computational efficiency for tractable simulation runtimes.

Main Results:

• The updated method effectively models the major implications of soil nutrient heterogeneity.
• It allows for accurate simulation of pasture production and environmental losses.
• The approach significantly improves computational efficiency compared to explicit heterogeneity representation.

Conclusions:

• The developed method offers a computationally efficient way to model nutrient heterogeneity in grazed pastures.
• This approach improves the accuracy of simulating pasture production and environmental nitrogen losses.
• The method is adaptable for other sources of spatial variability, such as variable fertilizer management.