Tuesday, November 14, 2006

Antibiotic Losses from Manure-Applied Sandy Outwash Soils.

Kuldip Kumar1, Satish Gupta2, Ashok Singh2, and Chander Yogesh2. (1) MWRD, 6001 W Pershing Road, R&D Dept, Section 123, Cicero, IL 60804-4112, (2) Univ of Minnesota, 1991 Upper Buford Circle, St. Paul, MN 55108

Antibiotics have been instrumental in treating infectious diseases that were previously known to kill humans and animals. However, it has now become clear that widespread use of antibiotics especially regular feeding in food-animals is not without problems. Although antibiotic dose is small (1 to 200 g per ton of feed), as much as 80% the antibiotic may pass through the animal in urine and manure unaltered. Since much of the manure is land applied, there is concern not only on the spread of antibiotic resistant bacteria to the environment but also on the potential of antibiotics appearing in water and food supplies. In this paper, we describe a study on antibiotic losses both in surface runoff and through leaching from land application of manure on highly permeable sandy outwash soils of Central Minnesota. In this region, the water table is relatively shallow (<5m) and is also a source of drinking water. The field study is located at the Central Lakes Ag Center at Staples, MN. The treatments are two manures types (hog and turkey), and two rates of antibiotics application (antibiotic present in the manure and antibiotic spiked manure). In addition there is also a control treatment where urea was the only source of fertilizer. Percolating water is collected with undisturbed drainage lysimeters whereas surface runoff is collected with runoff collectors. Antibiotics monitored are chlortetracycline and tylosin in hog manure, and chlortetracycline and virginiamycin in turkey manure. Preliminary results indicate that relatively there are minimal losses in surface runoff but leaching losses could be as high as 2% of the antibiotics applied.