Experiments

Experiment 278 - Effects of competition, herbivory and soil quality on switchgrass establishment and growth

In 2012, we initiated experiments on the growth and establishment of switchgrass cultivars and remnant populations at Cedar Creek prairie. We observed extremely low switchgrass establishment, 0 - 1.3%, despite irrigation and a disturbance treatment. There was severe insect herbivory (leaf removal) on 40-60% of cultivar seedlings, much higher as compared to herbivory on remnant switchgrass (12%). Also, phosphorus, potassium, organic matter, and pH were much lower at Cedar Creek as compared to a separate experiment (agricultural site) where we observed higher establishment of switchgrass. We propose two new experiments to test the effects of soil nutrients/properties and herbivory on establishment of switchgrass cultivars. In the first experiment, we will quantify seedling emergence and growth under a factorial combination of treatments: insect herbivory reduction (insecticide) and soil (sterilized) amendment (28- 0.64m2 plots). In the second experiment, we will test the independent and joint effects of herbivory and disturbance on the growth of transplanted cultivar and remnant switchgrass (144- 1 m2 plots). We request to expand our current experiment by 628 m2 and expect to complete all experiments by fall 2014. We will implement several pre-emptive and post-research activities to minimize the impact of this research: remove experimentally planted switchgrass, prevent cross- pollination with local switchgrass, and sterilize imported topsoil.

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