Agriculture Reference
In-Depth Information
ecosystems. Energy use relates to the use and
using up of non-renewable energy resources.
The use of cultivated land concerns the tempo-
rary non-availability of cultivated land as a
resource while it is being used for the produc-
tion of the crop.
Subsequently, the value representing the
impact indicator for each category of environ-
mental problem is calculated by multiplying
each type of resource used and each type of
substance emitted by a
characterization factor
for each of the categories of problem to which
the resource or substance can contribute. The
impact is expressed in equivalent kg of PO
4
for
eutrophication, equivalent kg of CO
2
for cli-
mate change, equivalent kg of SO
2
for acidifi-
cation, equivalent kg of 1,4-dichlorobenzene
for terrestrial pollution, in MJ for energy use
and in m
2
/year for land used for cultivation.
The characterization factors are quantitative
representations of the additional environmen-
tal pressure per unit of a given material emit-
ted. The characterization factors used in this
study are provided in van der Werf (2004).
This study concerned itself with hemp
production from a non-combined crop (i.e.
there was no production of hemp seed) and
seven other annual crops in France. The inputs
and yields for the eight crops are summarized
in Table 21.1. Where hemp is concerned, a
modification in farming practice (the use of pig
slurry and no-tilling) was also studied, together
with a more optimistic hypothesis regarding
nitrogen losses in the form of nitrates (20 kg/
ha instead of 40) (Table 21.2).
This study takes into consideration the
impact resulting from field production, includ-
ing harvesting, transport to the processing unit
and drying of the product (this only applies to
maize). The impacts resulting from the production
Table 21.1.
Inputs, yields and emissions for nitrogen in the form of nitrates (all in kg/ha) for hemp and
seven other annual crops produced in France.
Hemp
Sunflower
Rape
Peas
Wheat
Maize
Potato
Sugarbeet
Inputs
N (ammonium
nitrate)
75
85
110
0
130
100
170
220
P
2
O
5
(triple
superphosphate)
38
32
41
46
64
51
80
101
K
2
O (potassium
chlorate)
113
21
30
95
90
30
293
180
CaO
333
167
167
333
333
333
0
333
Seed
55
5
2.5
200
120
20
2,000
2.5
Pesticide (active
ingredient)
0
1.0
2.9
3.2
2.9
3.5
5.5
3.7
Diesel
65
79
81
87
101
91
165
137
Natural gas (for
drying the seed)
0
0
0
0
0
167
0
0
Agricultural
machinery
16.4
23.0
23.3
26.9
28.7
21.3
29.0
34.2
Grain yield dry
matter
-
2,100
2,970
4,110
5,910
6,440
-
-
Straw yield dry
matter
6,720
-
-
1,410
3,870
-
-
-
Dry matter yield
-
-
-
-
-
-
10,000
11,540
Followed by an
intermediate
crop (%)
a
0
0
0
0
50
0
0
0
Following crop
Wheat
Wheat
Wheat
Wheat
Maize
Wheat
Wheat
Wheat
NO
3
-N emitted
40
40
40
70
40
40
40
40
Note
:
a
Indicates the percentage of cases in which we believe an intermediary crop was sown between the harvesting of
the crop and the sowing of the following crop.
