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and 27% of the soil surface at 80 m 3 /ha. Ammonia emissions were equivalent to a
mean of 10% of the total N applied (range 7–14%) from the broadcast application
and a mean of 12% of the total N applied (range 7–20%) from the trailing shoe
application (Figure 2).
NH 3 loss (% N applied)
30
20
10
0
20 35 50 65 80
Application rate (m 3 /ha)
Broadcast
Shallow injection
Figure 1: Ammonia losses after shallow injection and broadcast slurry
applications to grassland in November 2003
The higher hydraulic loading from the trailing shoe slurry application (11–30 mm per
unit of surface area occupied by the slurry) compared with the surface broadcast
application (2–8 mm), meant that while the slurry stayed in a band, infiltration into
the moist clay soil was restricted (Table 1). Hence, the NH 3
emission patterns and
rates were similar from the two techniques, even though the emitting surface of the
trailing shoe application was only 18–30% that of the surface broadcast application.
Again, there was no relationship (P > 0.05) between broadcast or trailing shoe slurry
application rates and NH 3
emissions in March 2004.
NH 3 loss (% N applied)
30
20
10
0
Broadcast
Trailing shoe
20 35 50 65 80
Application rate (m 3 /ha)
Figure 2: Ammonia losses after bandspread and broadcast slurry applications
to grassland in March 2004
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