Alternative Management Options for the Control of Diffuse Phosphorus Loads to Lake Erie. Lake Erie Wastewater Management Study.

摘要

Available phosphorus soil test levels in Ohio and Michigan agricultural soils have increased steadily since the 1960's. These increases are reported here, by county, for those counties in the Lake Erie Basin of these two states. An economic analysis of phosphate fertilizer use in Ohio Lake Erie Basin counties for corn, soybeans and wheat, shows that there is an overuse of phosphate on corn and insufficient P fertilization of soybeans. P fertilizer use on wheat is at the economic optimum. The dissolved and particulate phosphate load reductions which could be obtained by reducing available P in agricultural soils from their 1980 levels down to the sufficiency level for corn and soybeans were estimated for the Ohio and Michigan Lake Erie counties. Reductions were small compared to the reductions which could be achieved with conservation tillage, but could become more significant if available phosphorus level in Basin agricultural soils continue to rise. The costs and phosphorus reductions obtainable with a side range of agricultural management practices were compared. Conservation tillage offered the most cost-effective means of greatly reducing the agricultural diffuse phosphorus load to Lake Erie. (Author)