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5
FAO/UNEP/UN-Energy Bioenergy Decision Support Tool -
MODULE 5: Land Resources
Table 2: Land use and nitrogen intensity of various energy crops used for biofuel production
Land use intensity
(ha/1000 GJ)
Rank
Nitrogen intensity
(kg N/1000 GJ)
Rank
Combined weighted
ranking
Sugar cane
2.3
2
110
2
0.02
Willow
5.3
6
90
1
0.03
Miscanthus
4.2
5
210
5
0.03
Sugar beet
1.9
2
460
8
0.03
Oil palm
3.0
4
440
8
0.04
Birch
6.8
8
160
3
0.04
Poplar
7.2
8
160
3
0.04
Switchgrass
6.5
8
300
6
0.05
Corn
4.9
6
490
8
0.05
Sweet sorghum
6.1
8
390
7
0.05
Algae
0.3
1
1100
11
0.05
Grain sorghum
16.2
12
1000
11
0.13
Rapeseed
16.5
12
1400
12
0.15
Soybean
20.2
13
3900
13
0.30
land is used for food, feed or fuel (Fischer et al 2010).
Land Resource Assessment
In order to determine what land is most appropriately used
for bioenergy feedstock production, a data-based top-down
approach can be complemented with ground-truthing in the
potential priority areas. The goal is to identify land that is both
suitable for the particular bioenergy feedstock or application, and
is also available in that it does not compromise food security or
use land that has signifcant social, cultural, ecological or environ-
mental value. The following steps can be taken in a land resource
assessment:
1. Conduct a land suitability assessment to identify land that
holds promise for feedstock production and map suitable
areas and potential yields;
2. Identify and map ecologically or environmentally sensitive
zones or “high risk” areas;
3. Identify and map existing agricultural production areas;
4. Assess the likely expansion paths for food and feedstock
production over the short to medium term;
5. Overlay infrastructure information on suitability and potential
yield maps to identify suitable areas with market accessibility,
which is a key factor in the economic feasibility of bioenergy
feedstock production;
6. Conduct “ground-truthing” of promising areas for feedstock
production.
The land resource assessment can be a complex exercise that
requires many different types of expertise: GIS analysts, remote
sensing specialists, agronomists, sociologists, ecologist, forests,
wildlife, meteorologist, soil scientists, water resources experts and
economists (UNEP, 2010). The signifcant cost and time needed
for such assessments means that it is important to match the
level of detail chosen in the assessments to the scale and scope
of bioenergy production that is envisioned. The different assess-
ments or approaches are explained in more detail below, including
land suitability, availability, infrastructure and ground-truthing.
LAND SUITABILITY ASSESSMENT
The land suitability assessment identifes areas of particular
promise for bioenergy feedstock production within the country or
region from a biophysical prospective based upon geo-referenced
data. It establishes a clear delineation of areas that can be used
to cultivate bioenergy crops and determines their potential yields.
The land suitability assessment consists of three steps (FAO,
2009a):
1. Establishment of the Land Resources Inventory, which is
composed of geo-referenced information and tabular data
that include :
a.
Climatic Resources Inventory:
containing information
on thermal climate zones (relation between temperature,
rainfall and altitude), length of growing period zones (identi-
fes the period when moisture availability and temperature
are conducive to crop growth) and evapotranspiration.
b.
Soil Resources Inventory:
containing information on soil
type, texture and phase and other factors.
c.
Landform Resources Inventory:
containing information
on the terrain and slope, which is used as a proxy for the
landform.
A Land Resources Inventory is composed of maps and tabular
data that synthesise the Geographic Information System (GIS)
database by administrative unit. The result is a geographically
referenced overview of the land resources that represent the base
for the suitability assessment.
2. Land Utilization Types (LUTs), defned as a combination of
crop type, input level and production system that would be
considered.
3. Implementation of the Land Suitability Assessment Criteria
are LUT- specifc and expressed in terms of constraint in
achieving the maximum attainable yield, defned based on
Source: Miller, 2009