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Table 3.3.2.
Total N uptake and marketable yield of calabrese crop at harvesting time, residual
nitrate N in soil profile to a depth of 250 mm of pore water storage on 14 November 1996 (
±
SD
,
n= 3).
N uptake
(kg N ha
−
1
)
Marketable yield
(DM ha
−
1
)
Residual N
(kg N ha
−
1
)
N
2
O-N emissions
(kg N ha
−
1
)
Treatment
N0
N1
N0
N1
N0
N1
N1
W
0
79
±
8
175
±
29
5.4
±
2.5
9.5
±
1.6
14
±
2 3
±
8
0.54
W
95
101
±
17
201
±
39
8.7
±
0.7 11.0
±
4.0
—
41
±
34
1.28
W
96
118
15
234
41
0.0
0
.7
8.0
0.9
—
37
4
15.55
±
±
±
±
±
Nitrous oxide emissions were measured using automated cover boxes sampling eight or four times
daily during the period 2 July-20 August 1996 (n= 1).
Fig. 3.3.1.
MOTOR simulations and measurements of microbial biomass C and N at Dipper field,
Balmalcolm Farm after PMS addition of 40 t DM ha
−
1
(C : N = 18) on day 165; 125 kg N ha
−
1
applied on day 185.
Soil biomass C and N measurements for the W
96
N1 treatment are
compared with MOTOR simulations in Fig. 3.3.1. Peak values of biomass
C and N are well simulated. However, the peaks occur up to 3 weeks later
than simulated (although more data are needed to confirm this). Biomass C
and N in the W
95
treatment were not significantly different from the control
treatment (not shown). We calculated the net effect of PMS on soil mineral
N by subtracting the mineral N in W
0
plots from W
96
values (Fig. 3.3.2).
Values on the day of PMS application were calculated from estimation
of the amount of mineral N added with the PMS (Gilboa
et al
., 2000).
The measured remineralization was slower than simulated, but MOTOR
simulations do not include crop uptake so simulations cannot be compared
directly with field data later in the season (after about day 230).
Nonetheless, simulated soil mineral N on 14 November 1996
(212 kg N ha
−1
) was much more than the sum of net (W
96
-W
0
) crop N
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