Diversifying crop rotations with temporary grasslands - Université de ...

The development of weed species richness showed a similar temporal pattern than weed
abundances (increasing in annual crops, decreasing in perennial crops, Dactylis in particular,
Fig. 12B). Moreover, spring-sown perennial crops had higher weed species numbers than the
corresponding autumn-sown crops. However, changes in species numbers (Fig. 12B, linear
scale) were much less pronounced than changes in weed densities (Fig. 12A, logarithmic
scale). This resulted in strong changes of the ratio between weed species richness and weed
plant density (Fig. 12C). This ratio decreased very quickly in all annual crops from 0.8-1 to 0-
0.1 while it progressively increased in the perennial crop treatments, in particular in the
Dactylis crops from 0.1 to about 0.7.
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