Fundamental Biochemical and Biotechnological Principles of Biomass Growth and Use 27
least reduce this emission. In contrast, if land is not disturbed over longer periods like
grassland or forest soil, the microbial soil biomass grows, thus binding carbon up to a
volume of about 30% of the grass or wood biomass above ground.
Modern agriculture is based on intensive land management. Farmers use extensive
machineries in preparing the soil, seeding, harvesting, processing, storing, and shipping.
Today, these machines run mostly on fossil fuel emitting CO 2 equivalent to about 11%
of the crop biomass harvest.
Last but not least, the high yields of modern agriculture heavily depend on adding
fertilizer to the soil, especially nitrogen. About 2–3% of the nitrogen applied escapes
in the form of N 2 O into the atmosphere. This small amount appears to be negligible;
however, its climate warming impact is 310 times higher than that of CO 2 (Tables 1.27
and 1.28) (Haberlet al.,2012).
Methane (CH 4 ) emitted from paddy fields and released by livestock husbandry
(especially ruminants) gives another biomass-related emission with a GHG (green
house gas) effect 21-fold more than that of CO 2 (Table 1.28). In Table 1.29, CO 2
equivalents are given, which consider the specific climate impact of different GHGs.
Biomass production does not come without any GHG emission. It is estimated that
about 20–50% of global GHGs originate from agriculture, livestock breeding, and
forestry (Table 1.28).
1.3.12 Regional Pillars of Competitiveness
Using renewable raw materials implies a significant impact on global feedstock regions
and industrial centers. As discussed before, fossil carbon sources are produced in
selected and manageable areas and are easy to ship globally through pipelines, tankers,
Table 1.27Options for carbon sources from agricultural, forestry, and industrial side
streams and carbon content (global; million tons per year) (Kircher, 2012).
Sugarcane
residues
Wheat
straw
Palm oil
wood
Wood
biomass
Sugar
processing
effluents
Palm
oil mill
effluents
Volume 530 350 114 900 300 480
Carbon content 265 175 67 450 4 16
Table 1.28GHG emission associated with biomass
production (% CO 2 fixed in harvested biomass) (Haberl
et al.,2012).
CO 2 from
soil (%)
CO 2 from
fossil fuel
(%)
N 2 OandCH 4
due to
fertilization (%)
Cropland 4 11 12
Grassland − 26 7 20
Forests − 32 3 1
Negative numbers mean that more CO 2 is fixed than emitted.
