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<br />New Roots for Agriculture
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<br />Prairie Studies
<br />Continue
<br />
<br />Holly Ewing
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<br />The fire in late March left the
<br />prairie black as it consumed the dry grass
<br />oflast year's growth. As spring became
<br />summer, then fall, I watched the prairie
<br />cover change. A cover of blackened
<br />, stubble slowly became a, blanket of greens
<br />dotted with a dazzling array of purple,
<br />blue, yellow, and white flowers and then
<br />metamorphosed into an autumn tapestry
<br />of brown, rust, imd purple grasses punc-
<br />, tuated with small surprises of asters,
<br />sunflowers, and goldenrods. This change
<br />happens every year with a multitude of
<br />subtle variations.
<br />The prairie is a complex, interde- ,
<br />pendent biotic community containing a
<br />multitude of plants, animals, bacteria,
<br />fungi, and viruses. Most of the plants are
<br />perennials (coming back eachyear from
<br />the same rootstock). These plants sprout,
<br />flower, and set seed at different times
<br />throughout the year. Some are tall; some,
<br />bushy. Others are small or thin. Some
<br />have roots in a fibrous mat close to the
<br />surface, while others have tap roots,that
<br />inay extend more th,m ameter into the
<br />soil. These plants give arid take different
<br />amounts of various nutrients 'from,the
<br />soil. Bacteria living in the roots of the
<br />legumes convert atmospheric nitrogen
<br />into a form that plants can readily assimi- '
<br />late. Some plant species do particularly
<br />well in dry years while others thrive in
<br />wet years.
<br />Even when agricultural crops
<br />shrivel and farmers turn them under,
<br />leaving the soil blowing in hot, dry winds,
<br />prairie plants grow and hold the soil hi.
<br />place. The Land Institute is interested in
<br />the prairie's durability and regenerative
<br />nature. In 1986 we began to gather data
<br />that would give us a better understanding
<br />of how the assemblage of plants changes
<br />over time. Jon Piper, our staff ecologist,
<br />has overseen the design and development
<br />of this study (See LR # 33, pg.23). Jon
<br />selected three sites of differing productiv-
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<br />12
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<br />ity on the Land Institute's unplowed
<br />prairie. These sites represent a gradient in
<br />soil fertility-from thin, rocky soil on a
<br />steep slope to a relatively deep, rich soil.
<br />Jon was particularly interested in both the
<br />species composition and the total amount
<br />of plant material each site would support.
<br />This year we added another rocky slope
<br />site of even lower productivity than the
<br />existing sites. Mark Gernes (1987 re-
<br />search fellow), Caton Gauthier (1988
<br />intern), Pamela Cubbage (1989 intern);
<br />and I have continued this project, writing
<br />up' each year's results for, the Land Insti-
<br />tute Research Report. ,
<br />Each year in May, June, and
<br />August, Jon and three to seven interns
<br />have taken twelve samples at each site
<br />along preestablished transects., Each of
<br />these samples came from a 0.5 x 0.5 m
<br />area in which we cut off all the above-
<br />ground growth and then separated it by
<br />species, a difficult task, I found, when the
<br />plants were smaller than my little finger.
<br />Back in the lab, we dried and weighed
<br />these samples. The data tell us how much
<br />growth occurs at each of the different
<br />sites, what species are where, when, and
<br />in what proportions, and how the growth
<br />and species composition changes over'time
<br />under variable conditions.
<br />We are now applying some of this '
<br />iriformation.in the design of new research
<br />projects. In our agricultural model of the
<br />prmrie, we have incorporated a cool
<br />season grass (Leymus), a warm season
<br />grass (Eastern gammagrass), and a
<br />legume (Illinois bundle flower). In one of
<br />our 1991 research plantings, we will plant
<br />different mixtures of these three species
<br />based on ratios of cool-season grasses,
<br />warm-season grasses and legumes ob-
<br />served at two of our prairie sampling sites.
<br />Even as we focus on questions about
<br />a sustainable agrlcu)ture, we have patches
<br />of prairie around us to explore and appre-
<br />ciate. As important as our chance to study
<br />the prairie plants in the name of "science"
<br />is our opportunity to experience a
<br />remnant of the ecosystem of this place and
<br />some of the beauty and diversity it con-
<br />tains.
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