Th. Misselbrook et al., SURFACE APPLICATION AND SHALLOW INJECTION OF CATTLE SLURRY ON GRASSLAND - NITROGEN LOSSES, HERBAGE YIELDS AND NITROGEN RECOVERIES, Grass and forage science, 51(3), 1996, pp. 270-277
An experiment was carried out over 2 years on grass and grass/clover s
wards in SW England to compare herbage yields and N recovery following
surface application or shallow injection of cattle slurry at three di
fferent times of application. In the second year, losses of N via ammo
nia volatilization, denitrification and nitrate leaching were measured
from applications to the grass sward. On the grass sward, there was n
o significant effect of time or method of application on dry-matter (D
M) yield in the first year, although shallow injection reduced apparen
t N recovery (ANR) in the herbage by 45% when compared with surface ap
plication. In the second year, shallow injection reduced DM yields by
26% and ANR by 48%. On the grass/clover sward, there were no significa
nt effects of time or method of application on DM yields or AWR in eit
her year. Inclusion of dicyandiamide (DCD) in the October slurry appli
cations had no significant effect in the first year, but in the second
year on the grass sward increased DM yield by 31% and 14% and ANR by
156% and 42% for shallow injection and surface applications respective
ly. Measurements in the second year on the grass award showed a reduct
ion in N loss by ammonia volatilization using shallow injection of 40%
and 79% for March and June applications respectively. Losses due to d
enitrification were greatest following October application, Shallow in
jection increased denitrification losses following March application,
but there were no significant differences following October or June ap
plications. N losses due to leaching were small, with no significant d
ifference between treatments. Reasons for the reductions in DM yield a
nd ANR following shallow injection, despite the large reduction in N l
oss by ammonia volatilization. are discussed.