Environmental Engineering Reference
In-Depth Information
2.1 Harvesting grass crops for silage.
Table 2.3 Dry matter yield of some annual crops; trial results from
Denmark, 2008-2009
Annual crop (commercial name)
Production of dry matter
(t DM/ha)
Beet (Hamilton) 23.2
Maize (Amadeo) 16.3
Jerusalem artichoke (Krogerup) 11.9
Hemp (Bialobrzeskie) 10.6
Source: Adapted from Madsen and Larsen (2011).
digestibility and the methane yield of the crop. Less mature crops, however,
have a higher moisture content, making storage difficult.
Sugar beet is harvested in temperate climates later than most crops,
usually in January (Murphy et al., 2011). Beet crops are excellent biogas
feedstock, as proven by trial results obtained in Denmark in 2009, where
beet provided 30-40% higher biomass yields per hectare compared with
other annual crops (Table 2.3). Beet crops also have a good uptake of
nutrients until late fall, reducing in this way the risk of nutrient losses to
groundwater.
The cultivation of energy crops requires a high input of fertilizers,
pesticides and energy for harvesting and transport. This reduces consider-
ably the environmental sustainability of their use for biogas and for
renewable energy production in general.
Search WWH ::
Custom Search