March 21, 2002 | By: Laura Skillman

Abandoned animal feedlots can have an impact on rural groundwater resources. A long-term study by the Kentucky Geological Survey and University of Kentucky College of Agriculture is looking at what can be done to eliminate the high nitrate levels found at some locations.

The project dates back to when a water well testing program was done in the 1990s, said Mike Smith, Henderson County Extension agent for agriculture and natural resources. During the testing, some farmers discovered elevated nitrate levels in their family wells. Some were corrected by replacing faulty well cases, but others were not.

Smith said they began looking to see what changes needed to be made agriculturally to reduce the problem in other wells. At one location, there was nothing the producer was doing today that was impacting the water. Instead, it was determined an old dairy site not used for 30 to 40 years was where the high nitrate levels were coming from.

The study has received several grants over the years to operate, and much of the work today is done by Glynn Beck, Kentucky Geological Survey.

The cooperative effort between all parties, especially the farmer, made the project work, said Smith. There was a lot of give and take within the project.

"We tried to do everything within the realm of operation of the farm," he said. "That's critical."

Smith said the research on the fragipan soils in Henderson can have statewide implications and beyond. Little work had been done on the effect of abandoned animal lots on fragipan soils, he said.

While an active lot contains animals, a semi-impervious, compacted soil layer forms from the animal traffic, Beck explains. That compaction, combined by the swelling wet manure, inhibits the vertical movement of nitrates. After a lot is abandoned, the manure and soil dehydrate and become cracked over a period of years. Once surface cracks form, percipitation can move vertically through the soil-manure and transport nitrates to the water table, he said.

Health risks associated with nitrates are particularly high in infants, pregnant women and persons of all ages with reduced gastric acidity. Elevated nitrate rates can also adversely affect livestock.

Current research has identified five abandoned feeding lots in western Kentucky. Four sites have high nitrate levels and septic tanks have been ruled out as a possible source. One of the sites is the dairy location. Groundwater samples in active row crop settings on the farm had nitrate levels four times less than the well, ruling out active farming practices as the cause.

Soil cores and monitoring wells were installed at the abandoned feedlot and from these soil cores a remediation plan was developed. Five hundred eighteen cubic yards of organic rich soil was removed and spread on a nearby pasture field. The excavated area was back filled with native soil and leveled to the original grade.

Funds are being sought now to sample monitoring wells and collect soil cores over the next three years to determine if nitrate concentrations begin to decrease within the soil column and shallow sandstone aquifer at the Henderson County site.

Additionally, Beck said he hopes to receive funding to determine locations of additional abandoned feedlots and to assess their impact on shallow groundwater resources in western Kentucky. Once sites are identified additional wells may be installed and soil cores may be taken, and additional site remediations may occur based on future findings.

Identifying these locations can aid in determining the environmental impact of abandoned feedlots. In the Green River Area Development District alone, Beck noted that more than 9 million animals were on farms between 1930 and 1999.

For more information contact Beck at (270) 827-3414.


Glynn Beck, (270) 827-3414 and Mike Smith, (270) 826-8387