The Ohio MSEA location at Piketon is adjacent to the Scioto River and overlooks an alluvial valley aquifer. The Scioto River is Ohio's second largest river, with a drainage area of 5,836 square miles. Of the one billion gallons of ground water produced each day in Ohio, over 70% is obtained from alluvial valley aquifers. Nationally, alluvial valley aquifers represent one of the most important sources of ground water.

The following farming systems are being evaluated at the Ohio MSEA site at Piketon: (1) continuous corn with chisel plow tillage; (2) corn/soybean rotation with chisel plowing following corn with no tillage following soybeans; and (3) corn/soybean/wheat-hairy vetch rotation with ridge tillage. Each practice has been established on separate 25 acre fields to provide sufficient land area for conducting ground water studies. Also, each phase of each rotation is replicated three times on 1 acre plots arranged in a randomized complete block design.

Routine sampling every 2-4 weeks includes above ground plant biomass and plant N content and soil sampling for chemical analysis. Three subsamples are removed from each plot. Cluster sampling without replacement is used to ensure that the three sampling locations are evenly distributed over the research plots. Soil cores for chemical analysis are obtained with a zero-contamination soil probe. The samples are analyzed for atrazine, alachlor, metribuzin, and nitrate at the USDA-National Soil Tilth Lab, in Ames, Iowa. Near surface soil samples are collected monthly and analyzed for extractable N and microbial biomass N.

Porous cup suction lysimeters to monitor agrichemical movement in the unsaturated zone. They are installed at 3, 6, and 9 feet depths at three locations in each of the 25 acre fields. Near each lysimeter bank, a neutron and frequency domain reflectrometry probe is used to measure soil water content distribution to depths of 9 feet.

The ground-water monitoring network is designed to quantify ground-water flow and quality on two scales. Thirty-seven wells were installed at the Ohio MSEA site, including 11 water table wells, 4 bedrock wells, and 22 multi-port wells. At 12 locations multi-port systems were installed which have sampling ports at approximately 12, 16, 20, and 24 feet below the soil surface. At 10 locations multi-port systems with sampling ports at the 40 and 60 feet depths in addition to the other depths were installed.