Mixed cultures for animal feed: maize/ runner bean mixture and phasin content

Growing a mixture of silage maize and runner beans could be an alternative to conventional silage-maize cultivation. The beans use the maize plants as a support, and are expected to increase the protein content of the maize silage. The question, though, is how yield and content of other substances change when the two crops are grown together. In particular, the effects of silage production on the phasin, which is toxic in the raw beans, are crucial for the use of this mixture as animal feed. In 2016 and 2017, the Liebegg Agricultural Centre tested the cultivation of a mixture of silage maize and runner beans in a field test without repeat. The bean variety «Anellino giallo» was sown in 2016, and «WAV 512» was used in 2017. In addition to determining yields, silages were also produced in bales and laboratory silos. Compared to maize grown on its own, the cultivation of a silage maize/bean mixture caused DM yields between the different variants to fall by 13–29 % in 2016 and 2017. Crude protein content was up to –10 to 36 % higher than with maize cultivation on its own. Phasin content, which is heavily dependent on the choice of variety, was not reduced by ensiling in bales, and was only slightly reduced by ensiling in the laboratory silos. For use in practice, the cultivation of bean varieties with a low phasin content is recommended.