In organic vegetable growing, nitrogen fixing green manure (GrM) play a key role in nitrogen supply for the crops. We investigated in two field experiments the influence of cutting and soil incorporation of GrM on nitrogen delivery for the proceeding crop cabbage. As a standard procedure, the GrM was mulched just before soil incorporation. In the first experiment the cutting regimes during growth of a grass-clover GrM (cultivated from Sept. to May; twice mulched or mown with removing oft the biomass from the field), had no effect on cabbage yield. However cabbage yield was 24% lower than the mulched or mown plots, when no cutting was performed during GrM growth. In a second experiment using a not frost resistant Phacelia-GrM or an over-wintering grass-ley (growing period Aug. to May), 45 kg soil mineral nitrogen was prevented from leaching. Phacelia augmented cabbage yield by 13% as compared to the yield from unfertilized, bare field plots. In contrast, cabbage yields were reduced by up to 10% after grass-GrM. At crop harvest, 15% of the nitrogen contained in the Phacelia biomass was recovered in the cabbage plants. Mulching and subsequent soil incorporation of the GrM within one to two days lead to similar or even better nitrogen efficiency as compared to more labour intensive practices.
Spring J.-L-, Zufferey V., Verdenal T., Reynard J.-S., Lorenzini F., Bourdin G., Blouin A., Carlen C., Jermini M., Morisoli R., Ferretti M.
Five Merlot clones bred in Switzerland are currently being distributed by the certification sector. A multiyear trial conducted by Agroscope in Gudo (Canton of Ticino) has made it possible to compare them with French and Italian reference clones and to highlight their very good performances.
Arbuscular mycorrhizal fungi are important for healthy soils and crops. A pan-European study shows that plant-protection products adversely affect these fungi, reducing their ability to supply plants with phosphorus via their roots.
Birdsfoot trefoil and sainfoin are used in mixtures for perennial hay meadows and for tannin-containing fodder. Agroscope is adding two new cultivars of birdsfoot trefoil to the ‘List of Recommended Varieties of Forage Plants’, whilst there is no change in the case of sainfoin.