Amending woodchip bioreactors with corncobs reduces nitrogen removal cost.

Woodchip denitrification bioreactors are an effective agricultural practice to reduce nitrogen (N) export from subsurface drainage via the conversion of nitrate (NO) to nitrogen gas (N), but there are challenges associated with limited woodchip supplies and increasing prices. Previous lab studies indicate that corncobs could be a promising woodchip alternative from the perspectives of N removal rate and cost. This field study aimed to provide early performance and cost assessment of denitrification bioreactors with two woodchip-corncob treatments.

Stacked conservation practices reduce nitrogen loss: A paired watershed study.

Combinations of best management practices (BMPs) are needed to achieve nutrient reduction goals in the Mississippi/Atchafalaya River Basin (MARB), but field results are crucial to encourage stacked adoption of BMPs. A paired catchment-scale study (2015-18) was done to assess the impact of (i) BMPs, (ii) precipitation patterns, and (iii) seasonality on nitrogen (N) export. Flow-weighted samples were collected and analyzed for total ammonia nitrogen (TAN), nitrate (NO-N), and total nitrogen (TN).

Impact of stacked conservation practices on phosphorus and sediment export at the catchment scale.

Best management practices (BMPs) are effective in reducing nutrient and sediment export, but further understanding of the benefits of the stacked BMPs is needed. This catchment-scale study was established to evaluate the impact of hydrology and BMPs on phosphorus (P) and sediment losses. Two adjacent catchments, one with a lower level of BMP adoption (Low-BMP #11) and one with a higher level (High-BMP #12), were compared for total P (TP) and total suspended solids (TSS) export.

Spatial and temporal distribution of E. coli contamination on three inland lake and recreational beach systems in the upper Midwestern United States.

Swimming advisories are commonly posted at public beaches across the United States every year. In Iowa, weekly monitoring of public swimming areas at state and county beaches have resulted in the impairment of numerous lakes for fecal indicator bacteria (FIB) contamination, as detected by E. coli.

Long-term impact of poultry manure on crop yield, soil and water quality, and crop revenue.

A long-term poultry manure fertilizer study was initiated in 1998 and continued until 2009 under corn-soybean (CS) rotation. To match changing landscape trends, the plots were switched to continuous corn (CC) from 2010 to 2017. In both CS and CC phases, poultry manure (PM) was applied at the crop rotation recommended agronomic N rate and either half (CC phase) or double (CS phase) the recommended rate.