Cover crops : Protection of the environment with cover crops and conservation agriculture
Conservation agriculture maintains the long-term productivity and functionality of agricultural soils. The project "Cover crops" aims to further improve ecological soil management by growing intermediate crops.
Background (completed research project)
Harmful consequences of modern agriculture such as soil erosion or decreasing soil quality could be eased by reducing mechanical soil disturbance or avoiding it altogether with a no-till approach. But such approaches require more herbicides and fertilisers to secure yields. Cover crops that are grown as part of the crop-rotation approach of conservation agriculture can keep weeds down, improve nutrient availability and stabilise soil structure. Up until now, it has been unclear which cover crop systems and seed mixtures produce the best results.
The project aimed at identifying suitable cover crops that will enhance the environmental benefits of conservation agriculture and analyse their ecosystem services.
Leguminosae, in particular field peas and vetches, that are grown as cover crops between two main crops, suppress weeds efficiently and produce nutrients for successive crops. If a mix of varieties is grown, the biomass production is higher than in monocultures. This in turn improves the ecosystem services. Cover crops are particularly successful if they are sowed immediately after the previous crop is harvested and if the cover crop is carefully selected in view of the expected benefits.
Implications for research
All trials were conducted on fields that are managed according to conservation agriculture. Adapted seeding technology was used. On this basis, successive field trials can be conducted. We now have a better understanding of cover crop plants and how various varieties can be combined and we know more about soil-plant interaction in conservation agriculture.
Implications for practice
The project showed that the use of herbicides and fertilisers can be reduced if cover crops are used in conservation agriculture. It demonstrated that it is environmentally desirable and economically viable to grow such crops even though their only purpose is protecting the soil.
Cover crops for conservation agriculture (CC4CA)
- Dr. Bernhard Streit, School of Agriculture, Forest and Food Sciences (HAFL), Zollikofen
- Prof. Achim Walter, ETH Zurich
- Dr. Raphaël Charles, Institut de recherche de l'agriculture biologique, FiBL, Nyon