Agriculture Reference
In-Depth Information
m 2 /m 2
3.0
1.2
1.2
1.0
1.0
2.0
0.8
0.8
0.6
0.6
1.0
0.4
0.4
0.2
0.2
0
60
120
0
60
120
0
60
120
amount of nitrogen in kg/ha applied on April 3
Fig. 9.17 Effect of nitrogen on the leaf-area-index (LAI) and on the chlorophyll content of winter-
wheat in Indiana, USA. The chlorophyll mass per unit of field area in the right graph is the product
of the leaf-area-index in the left graph and the chlorophyll mass per unit of leaf area in the central
graph (Compiled from data by Hinzman et al. 1986 )
4
30
3
20
2
10
1
March
April
May
June
March
April
May
June
Fig. 9.18 Effect of nitrogen on leaf-area-index and on chlorophyll content of winter-rape (winter-
colza) in Schleswig-Holstein, Germany. For the fertilized plots, the crop was dressed with 40 kg of
N per ha respectively at the end of March, at the end of April and at the beginning of May. Hence
for these plots, the total amount of N applied in the spring was 120 kg per ha (From Kappen et al.
1998 , altered)
Research by Hinzman et al. ( 1986 ) with wheat and by Kappen et al. ( 1998 ) with
rape (colza) revealed the effect of nitrogen on the chlorophyll concentration within
the leaves as well as on the leaf-area-index. It can be seen from Figs. 9.17 and 9.18
that nitrogen changes the leaf-area-indices much more than the chlorophyll concen-
tration within the leaves. The dominating effect of nitrogen on biomass production
 
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