Analyzing key constraints to biogas production from crop residues and manure in the EU—A spatially explicit model
Fig 4
DM and C:N ratio of combined crop residues and manure.
(a): DM concentration in the available substrates. (b): C:N ratio of the available substrates. Both maps concern the base scenario (see parameters in Table 4). C and N contents of substrates are given in Table 3. Striped areas are not analyzed.