Wastewater Irrigation Effective on Bermudagrass
Hay By Ann
Perry January 22, 2009
Farmers in North and South Carolina already make every drop of water
count by recycling livestock wastewater for irrigation. Now
Agricultural Research Service (ARS)
scientists have found ways to boost benefits from this practice even more.
The high nutrient content of livestock wastewater can limits its use
for crop irrigation. In addition, spray irrigation can increase the emission of
ammonia and other volatile organic compounds present in the wastewater.
ARS research leader
Hunt, agricultural engineer
Stone and soil scientist
Vanotti wanted to see if subsurface drip irrigation (SDI) with pretreated
swine wastewater could both eliminate emissions and increase the overall
effectiveness of irrigation. Hunt, Vanotti and Stone all work at the ARS
Plains Soil, Water and Plant Research Center in Florence, S.C.
They conducted a two-year study that compared bermudagrass hay crops
that were irrigated via SDI. One crop was irrigated with livestock wastewater
that had been pretreated to remove concentrations of ammonia, nitrogen and
phosphorus. The other crop was irrigated with well water and amended with
The team assessed the crops from both management systems for yield and
hay biomass. They also checked soil nutrient levels and soil water nutrients.
The scientists found that crop yields were higher for bermudagrass
that had been irrigated with the pretreated wastewater. They also found that
bermudagrass hay yields did not vary significantly when the crops were
irrigated with wastewater levels that replenished only 75 percent of the water
lost to evapotranspiration.
This suggests that wastewater SDI is often effective at lower
application rates. SDI irrigation with treated wastewater would also reduce the
amount of water draining through the soil, which in turn would reduce the
opportunity for plant nutrients to be leached below the root zone.
These results imply that SDI with treated swine wastewater provides
forage crops with needed irrigation and fertilization that can equal--and even
sometimes exceed--the benefits of feeding crops with commercial fertilizer.
about this research in the January 2009 issue of Agricultural Research
ARS is a scientific research agency of the
U.S. Department of