Kura clover is an unusual species – a legume that spreads by rhizomes. It is both drought tolerant and cold tolerant, making it well-suited to the Upper Midwest. Because it is rhizomatous it can spread to fill in thin areas, unlike most other legumes. Colleagues at the University of Wisconsin have taken advantage of this in developing a kura/corn companion cropping system for dairy operations. The kura provides a permanent living mulch in which strips can be created by tillage or herbicide for planting corn. As they decompose, the killed strips release nitrogen that can be used by the growing corn, while the remaining living clover gradually regrows over the row, fixing more N as it grows.
We are exploring the use of kura clover in companion cropping systems where the corn is harvested for grain and the corn stover is harvested for biofuel production, on the presumption that the kura clover will provide erosion protection, maintain soil carbon, and reduce the need for inorganic N fertilizer. We use eddy covariance systems to measure carbon gain and water loss in both rainfed and irrigated companion crop systems, where we are also measuring soil carbon changes.
One of the problems with kura clover is that it is difficult to establish – seed is hard to find, and when planted it is slow to establish. To alleviate these problems, we are testing field-scale methods for vegetative propagation, described in a short video.