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Building a 2,000-square-foot house leaves about a ton of gypsum wallboard waste from end cuts, window and door cutouts, and broken boards. In the United States, three million tons of gypsum wallboard waste is dumped in landfills each year. In addition to depleting space, microbial action can decompose gypsum to malodorous hydrogen sulfide gas, which at high enough exposures can cause irritation of the mucous linings, headache, dizziness, nausea, convulsions, coma, and death. A study at the University of Wisconsin at Madison by soil scientist Richard Wolkowski, published in the January-February 2000 issue of Communications in Soil Science and Plant Analysis, found that clean scrap gypsum wallboard can be crushed and applied to alfalfa as fertilizer. Alfalfa covers over three million acres in Wisconsin and is fed to dairy cows and other livestock. This crop requires large amounts of sulfur as a nutrient. Although commercial gypsum fertilizer has existed for a long time, says Wolkowski, crushed gypsum wallboard waste provides a way to reduce construction waste while nourishing the soil. For three growing seasons, crushed wallboard was spread on alfalfa fields at four University of Wisconsin agricultural research stations with different soil types and climates at rates ranging from 1 ton per acre to 16 tons per acre. Alfalfa yields were similar to those from fields treated with commercial gypsum fertilizer. " [Crushed wallboard] had neither a strong positive nor negative agronomic effects on alfalfa production," Building better crops. Scientists spread crushed gypsum wallboard on alfalfa fields as a fertilizer.