Vegetative Covers to Control Sediment and Phosphorus (P) in Runoff from Dairy Waste Application Fields
ASABE Annual International Meeting , 2008

Giri, S., Mukhtar, S., Wittie, R.

Excessive Phosphorus (P) in runoff contributes to eutrophication of fresh water bodies. Studies have shown that manure and effluent from animal feeding operations (AFOs) applied to waste application fields (WAFs) have contributed to excess P in segments of the North Bosque River in east central Texas. There is a growing need for environmentally sound, economically viable, and easy to establish best management practices (BMPs) to control such pollution. Vegetative buffer strips offer a potential solution for reducing runoff P from WAF by extracting it from soil and by reducing sediment P delivery to streams by decreasing runoff and soil erosion. In a field study, eight plots (5m × 5m), were assigned to four replicated treatments namely control (bare, plant cover) cool season grass, warm season forb, warm season grass, and warm season legume to assess their efficacy of runoff sediment control and P sequestration potential from soil. These plots were established on a coastal Bermuda grass WAF that received dairy lagoon effluent. A runoff collection system; a 1m × 1m sub-plot with a runoff conveyance and collection apparatus, was established on the upstream and downstream margins of each plot. Natural rainfall runoff samples were collected and analyzed for total P, soluble P, and total suspended solids (TSS). Additionally, the total mass of runoff collected from each sub-plot was estimated. Results show that the warm season forb (perennial sunflower), and warm season grass (switchgrass) were the most effective treatments for reduction of runoff P, followed by coastal Bermuda, and cool season grass.