Diversifying crop rotations with temporary grasslands - Université de ...
Diversifying crop rotations with temporary grasslands - Université de ...
Diversifying crop rotations with temporary grasslands - Université de ...
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Table 3: Four strategies for combining agricultural production and biodiversity conservation.<br />
The four strategies lie on a gradient between separation and integration, as illustrated in Fig. 5.<br />
What is preserved?<br />
Fragmentatio<br />
n of habitats<br />
Use of ecosystem<br />
services?<br />
Problems<br />
Crop yield<br />
risk of weed,<br />
pest, disease<br />
invasions<br />
‘Spatial separation’<br />
‘Wildlife friendly farming’<br />
(no spatial separation)<br />
1) Large-scale 2) Small-scale 3) Temporal<br />
4) Complete<br />
spatial separation: spatial separation: separation:<br />
integration:<br />
Large ‘untouched’<br />
nature reserves and<br />
regions of intensive<br />
production<br />
Static mosaic of<br />
productive fields and<br />
‘unproductive’ zones<br />
Dynamic mosaic of high<br />
productive <strong>crop</strong>s and<br />
less productive periods<br />
on <strong>crop</strong> rotation scale<br />
Productive and<br />
unproductive organisms<br />
coexist at the same place<br />
and time<br />
Separation Integration <br />
Natural areas <strong>with</strong><br />
associated ‘wild’<br />
organisms<br />
Some organisms typical for farmed landscapes (and<br />
some ‘wild’ organisms<br />
Organisms typical for<br />
farmed landscapes, no<br />
space for ‘wild’ species<br />
Large-scale Medium scale Low<br />
No<br />
No ‘untouched’ nature<br />
and no space for huge<br />
reserves in Europe<br />
Some (needing spatial<br />
migration of organisms)<br />
small size of protected<br />
areas<br />
Maximum on productive parts? But no production<br />
on ‘spared’ land<br />
High? (no mechanisms<br />
of auto-regulation)<br />
A.III.8 Crop rotation<br />
18<br />
Some (needing spatial<br />
migration of org. or<br />
temporal outlast of<br />
positive effects)<br />
Spatio-temporal mosaic<br />
of high and low yield<br />
fields<br />
Immediate,<br />
<strong>with</strong>out spatial or<br />
temporal restrictions<br />
No optimal weed<br />
infestation level, no steady<br />
balance possible<br />
Permanently reduced<br />
yield?<br />
? ? Low?<br />
The main benefits of rotating different <strong>crop</strong>s on a given field are (1) the maintenance of soil<br />
fertility and (2) the regulation of weeds, pests and diseases. Both may contribute to increase<br />
<strong>crop</strong> yields and reduce the need of inputs compared to monocultures (Smith et al., 2008).<br />
Historically, the soil fertility has often been restored by letting the field lie fallow for about<br />
one year after 1-3 years of wheat, barley, oats or other cereal <strong>crop</strong>s. In central and northern<br />
Europe, such ‘food-feed-fallow’ <strong>rotations</strong> were probably introduced by the Romans about<br />
2000 years ago. Between about 1700 and 1800, European farmers gradually replaced the<br />
fallow phase by sown grass or legume forage <strong>crop</strong>s that were grazed by livestock. They<br />
adopted four-year <strong>rotations</strong> including e.g. cereal grain <strong>crop</strong>s, root <strong>crop</strong>s and forage <strong>crop</strong>s<br />
(Freyer, 2003). Fields were thus always planted for food or feed increasing the overall