Insect diversity and insect numbers in pure corn cultivation and in co-cultivation of corn and beans were investigated and compared at four locations in Germany. The initial results are promising: At three of the four locations, there were more chalcid wasps where mixed cropping was conducted; overall, there was a slight trend toward more bees and a greater frequency of beetles and thrips when corn and runner beans were grown together. “Co-cultivation of corn/beans helps create diversity in agriculture, and we’re naturally delighted that initial study results confirm that," said Philip Jung, Head of Corn Marketing at KWS Germany. "Farmers also benefit from a higher protein concentration in feed when the crops are used together as silage, since beans per se have a higher protein content than corn.”
Several years of intensive research and development work were required before KWS was able to offer this mixed cropping commercially. A suitable corn variety and the right bean variety had to be found, for example. Beans naturally contain the protein phasin, which may be harmful to people and animals in large concentrations. Beans are therefore cooked for human consumption, since high temperatures destroy phasin. As cattle feed cannot be boiled, a bean with a low phasin content was required. Together with the University of Göttingen and the vegetable breeder Sativa Rheinau AG, KWS tested several hundreds of bean varieties before finding the right one. The bean varieties now offered by KWS have a very low phasin content. Experiments by the TUM School of Life Sciences Weihenstephan and the University of Hohenheim have also confirmed that the digestive juices from a cow’s rumen can break down phasin and that feeding cows corn/bean silage is harmless.
“We attached a very great deal of importance to developing co-cultivation of corn and beans on a sound scientific basis,” emphasized Jung. “We are launching it here in Germany under controlled conditions so that we can provide farmers with individual consulting. Demonstrable, carefully thought-out quality in all areas has top priority.” As part of that, KWS is in continuous dialogue with experts and scientists from the whole of Germany so as to discuss experience and findings related to mixed cropping. “The expectations on us to find new solutions that promote diversity and protect insects are justified and enormous. The issue of sustainability is also of great importance for us as a seed producer. We’re searching here for feasible solutions and delighted that the latest figures from the University of Hohenheim and Julius Kühn Institute now also show the major contribution our mix of corn and beans makes to increasing biodiversity on fields,” said Jung.