Agriculture Reference
In-Depth Information
70
Other spp.
S. macleayi
M. dubius
A. trapezoides
b
b
60
50
b
40
30
20
a
10
0
0 30 60 120
Dry Biosolids (t/ha)
FIGURE 14.5
Average abundance of earthworms in pastures at Goulburn, New South Wales, with varying
amounts of dewatered biosolids incorporated into the soil 7 years earlier. Different letters above the histograms
indicate significant differences between treatments (for total earthworms). (Data redrawn from Baker 2002b.)
80
30
Earthworm Population
Earthworm Biomass
70
25
60
20
50
40
15
30
10
20
5
10
0
0
0 10 75 150
Clay (t/ha
-1
)
FIGURE 14.6
in a nonwetting sand below a
pasture at Mingbool, South Australia, in treatments with varying amounts of added clay (0 to 150 t ha
−1
).
Different letters above the histograms indicate significant differences between treatments. (Data redrawn from
Baker et al. 1998a.)
Average abundance and biomass of
Aporrectodea trapezoides
plots, and the plant species composition changed (i.e., more weeds). The mechanism driving the
change in earthworm populations was not clear. Nevertheless, both Kingston (1989) and Lobry
de Bruyn (1993) suggested that mortality of
in irrigated dairy
pastures in Tasmania is caused, at least in part, by direct animal trampling effects, exacerbated
by greater surface activity in moist soils, and by compaction of the soil, which renders it unsuitable
for earthworm survival.
With smaller domestic animals, Hutchinson and King (1980) observed that earthworm popu-
lations were highest at a stocking rate of 29 sheep ha
A. caliginosa
and
L. rubellus
−
1
in pastures in northern N.S.W. This stocking
