Modeling the Nitrogen and Phosphorus Inputs and Outputs of Financially Optimal Irish Beef Production Systems

Abstract

Challenges currently faced by beef producers in Ireland include reducing their adverse environmental impact and maintaining farm economic margins. Fertilizers are essential for productive farming but they can be harmful to the environment when inappropriately or excessively applied to crop and pasture land. A linear programming model was used to identify financially optimal strategies for calf-to-stocker and calf-to-finish beef cattle production in high- and low-price market scenarios. The high-price scenario resulted in an increase in gross margin of $1,700 and $13,000 on a 40-ha farm for the stocker and finisher options, respectively. The impacts of these systems on environmental indicators were investigated through farm simulation. In general, the high-price scenarios were more intensive and had greater environmental impacts when compared to the low-price scenarios. Nitrogen leaching losses were quantitatively the most important environmental indicator on well-drained soils with a maximum annual loss of 72 kg N/ha. Volatilization and denitrification losses of nitrogen (N) were also relatively high where more intensive production was practiced with annual losses of 48 and 23 kg N/ha, respectively, in the most intensive scenario identified. Predicted phosphorus losses were small although annual accumulations in the soil of up to 7.5 kg P/ha may lead to greater losses in the future. On poorly drained soils, volatilization losses were greatest with leaching losses in this case the lowest of the loss pathways investigated. Further reduction in inorganic nitrogen application has the potential to reduce N losses, but predicted concomitant reductions in farm gross margins were also considerable.