Nitrogen Flow on Two Livestock Farms in Ontario:

Abstract

Improving N utilization on livestock farms reduces the requirement for external N inputs and also reduces the risk of soil, air and water pollution. Calculation of N flow on two livestock farms in Ontario showed that 17-21% of imported N was exported as farm products. A simple model was developed for livestock farms to measure the change in farm N utilization following improvements in N utilization by animals through changes in diet, increased N retention during manure collection and storage, and increased manure N utilization by crops following field application. On a dairy farm, improving N utilization by dairy cattle from 16% to 25% through changes in animal diet increased the whole-farm N utilization from 18.8% to 22.1%. The highest priority for improving farm N utilization and decreasing the risk of environmental pollution on livestock farms is by improving N utilization by animals through improved feeding strategies.