1.3. Positive crop-rotation effects: the example of crop residues
Crop residues remaining on the field have great influence on the creation
of positive crop-rotation effects. Even though the occurrence of
crop residues is not restricted to crop rotations, as they may also occur
in monoculture, they serve as good example for effects between different
crops grown on the same field. The extent to which crop residues remain
on the field depends on farming practices. We assume that their
relevance might be higher in deliberately created crop rotations, compared
to rotations with less different crops in the rotation or systems
without any crop rotation. Independently, whether in long crop rotations
or in monoculture, crop residues remain on the field and affect
the subsequent crops by positively influencing physical, chemical and
biological soil properties, thus helping to maintain or even improve
soil fertility from one crop to the subsequent one. In a review about
crop residue impacts, Blanco-Canqui and Lal (2009) describe functions
of crop residues in the soil (Table 1).
The next section provides an overview of currently available
methods to include crop-rotation effects in LCA