Effect of Alternative Herbicides on Suppression of Kura Clover.

Living mulches are growing in popularity as a way to maintain ground cover and soil quality. In living mulch systems, perennial cover crops are grown alongside commodity crops and persist as winter covers. Kura clover is a leguminous perennial that is useful because of its ability to biologically fix nitrogen (N), and is also well-suited to the Upper Midwest due to its winter-hardiness.  While kura clover has typically been controlled with herbicides to prevent it from outcompeting commodity crops, methods for controlling kura clover in organic systems has not yet been studied.  In this experiment, we seek to answer 1) How effectively do alternative herbicides decrease kura clover photosynthesis, and 2) Do alternative herbicides spur varying levels of N rhizodeposition?  To do so, we measured clover photosynthetic response to, and N release via potentially mineralizable N (PMN) of growing media from, six suppressive herbicides: 1) glyphosate at 1 kg a.e. ha-1,2) glyphosate at 1.5 kg a.e. ha-1,3) Wilt Pruf © (an anti-transpirant), 4) Vinagreen at 20% acidity, 5) Vinagreen at 30% acidity, and 6) Weed Zap (clove and cinnamon oils), plus a no suppression control. Although we predicted that glyphosate would best suppress kura clover, preliminary photosynthesis data suggest Vinagreen was most effective in this respect. Results will also discuss PMN of growing media to evaluate rhizodeposition.