RESUMO
County-level agricultural statistics were aggregated at the watershed level to provide estimates of trends in land use and agricultural management in the Maumee and Sandusky River watersheds during the period 1975-1995. Average farm size increased by 40% or more, but the number of farms decreased by nearly 40%; the total land area in agriculture also decreased, but only by about 7%. Conservation tillage increased from virtually nothing to nearly 50% of cropland in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.]; most of the change is due to adoption of no-till soybean. The Conservation Reserve Program has enrolled more than 75,000 hectares, but this represents less than 5% of total farmland. The great majority of land classified as highly erodible has been placed under treatment during the study period. Cropland in soybean has increased; land in wheat (Triticum aestivum L.) and hay has decreased. Cropland in corn has decreased in the Maumee watershed and increased slightly in the Sandusky watershed. Average per-hectare yields of corn, soybean, wheat, and hay have increased by 10 to 40%. Fertilizer phosphorus sales increased until about 1980 and have declined significantly since then; fertilizer nitrogen follows a similar but less pronounced pattern. The decreases are more substantial in the Maumee watershed than in the Sandusky. Manure use for fertilizer has also declined significantly.