The nutrient supply of winter wheat was one of the topics investigated by the DOC long-term system comparison from 1978 to 2003. The aim of this trial is to provide evidence of nutrient-related yield limitations in organic farming systems. Substantial differences in yield between «organic» and «conventional» farming systems and different fertilisation intensities were primarily attributed to the delivery of nutrients – in particular, nitrogen – to the plants. Because the soil phosphorus supply was adequate in all DOC systems over the entire trial period, phosphorus was ruled out as a co-limiting factor. The plant analyses of straw and grain exhibited high figures and a low differentiation for phosphorus, thus confirming the soil findings. By contrast, potassium was identified along with nitrogen as a co-limiting factor in the organic systems at the low fertilisation intensity and in the unfertilised control. This was indicated by the differentiation of potassium content in the above-ground biomass and the available soil potassium content. Despite this, both the biodynamic and bio-organic system exhibited a balanced potassium supply at the high fertilisation intensity. Both bio-systems may therefore be considered sustainable at this fertilisation intensity.
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.
Tall oat grass and golden oat grass are typical hay-meadow grasses that are also suitable for forage mixtures. Of the four tall and three golden oat grass varieties tested, only one new variety of tall oat grass is likely to make it onto the List of Recommended Varieties.
Stevenel P., Wendling M., Brabant C., Suss H., Savoyat C., Dierauer H., Mascher F., Charles R.
FiBL and Agroscope investigated bread wheat varieties to determine their yield and quality stability. The results show that the choice of variety must be adapted to the site and that high yield potential does not go hand-in-hand with a high protein content.