Prairie

Abstract

In June 1983 4 ha of steep slopes and ditches around an earth dam in eastern Iowa were extensively reshaped with a bulldozer. The season was too dry to expect a perennial cover crop to establish, and slopes were too steep to recommend using tractor or tillage later, following establishment of a temporary cover crop. An innovative seeding method was deemed necessary. The method chosen was to broadcast oats heavily (100 kg/ha) on the cloddy surface and mulch them thoroughly (90-100% coverage) with spoiled hay. One August rain followed by normal autunm precipitation produced a good temporary stand of oats, and by late autumn the original mulch was mostly decomposed. A mid-November weather forecast predicted that a sleet storm would arrive with the next front. Seed of birdsfoot trefoil (Lotus corniculatus) was immediately broadcast through the dead standing oats (10 kg/ha). The storm’s force then matted the oats down over the seed. Two 1-m2 miniplots were also sown; one to big bluestem and the other to lance-leaved coreopsis (Coreopsis lanceolata), at rates of approximately 14 kg/ha (PLS) and 11 kg/ha, respectively. All three species apparently benefited from the winter stratification and protection under the oat layer. Weeds, along with some self-seeded oats, were the most obvious 1984 crop. Along with the dead oats, which remained functionally rooted until early summer, weeds provided much of the erosion control. However, by 1985 the three intentionally planted species were dominant, with good stands developed in their respective areas. Variations of this method might be useful for establishing prairie plantings under similarly adverse circumstances. For example, the cover crop could be matted mechanically over a "frost seeding" rather than waiting for an opportunity to plant before an approaching storm.