Miner Institute researcher tells committee tile drainage cuts surface phosphorus but raises nitrogen trade-offs

Laura Klyber, a researcher at Miner Institute, told a legislative committee that tile drainage on poorly drained clay soils in the Lake Champlain basin reduces surface runoff and erosion and, in many cases, lowers total phosphorus losses but typically increases overall drainage volume and nitrogen export.

Klyber said the Miner Institute — a research and education dairy farm in the northeastern corner of the state that operates about 1,300 acres of cropland and a roughly 500–550 milking-cow herd — has used paired-plot and field-scale monitoring to compare tiled and untiled management and to quantify effects on nutrient transport.

"We had a lot more tile drainage, a lot more drainage overall, but that was occurring with an 86% decrease in surface runoff," Klyber said. "Despite that, those lower concentrations found in the tile drainage and ultimately, we came out about even across the two treatments." She described a single…