DYIF8GHH

2761

5 janvier 2021 17:06

5 janvier 2021 17:06

Recent meta-analyses assessing the impact of organic farming on plant species diversity showed that positive effects mainly occurred at a small scale while benefits at the farm or landscape level were less pronounced. The studies also detected that common species were more favored by organic farming than rare ones. In a farm scale study in southern Bavaria, Germany, we analyzed how the conversion to organic farming changed arable plant communities over a 23-years period and questioned the impact on weed management and species conservation. Vegetation sampling started two years before this conversion. At the end of the study period, crop cover had slightly decreased but yields of winter cereals (5.2 t/ha) still achieved 78% of the pre-organic harvest. Arable plant cover increased from 2 to 40% and the soil seed banks enlarged from 4200 to 33,300 seeds m-². Total numbers of plant species increased by 46% at the plot level and by 22% at the farm level, plant species characteristic of arable fields increased by 50% and 19%, respectively. Populations of both threatened and problematic plant species clearly profited from the conversion. Our results generally confirm that organic farming benefits plant biodiversity in arable land. Such benefits being more pronounced at the plot scale verifies previous studies, however, these effects were also visible over the whole arable area of the farm. A significant increase in the cover of insect-pollinated plants indicated that organic management can also support ecosystem functions. Our data prove that long-term organic farming can increase nature conservation value of the arable flora with only a moderate setback of crop yields.

None

• AB - Spécifique
• FREDO conversion en AB
• FREDO durabilité
• FREDO environnement
• GEO Allemagne
• arable plants
• biodiversité
• crop yield
• pollinator plants
• rare plant species
• soil seed bank
• species diversity
• weeds

TUEXENIA

40

291-308

November 9, 2020

9 novembre 2020