Nitrogen and phosphorus losses from a feedlot for suckler cows

Authors

• J. UUSI-KÄMPPÄ

DOI: https://doi.org/10.23986/afsci.5735

Abstract

The raising of cattle outdoors in winter is becoming more common in temperate areas, although there is little information available on the effects of this practice on forested environments. In this study, the concentrations of ammonium acetate extractable phosphorus (P AAAc )and mineral nitrogen (NH 4-N and NO 3-N) in soil and the quality of percolation water from an open feedlot were studied in eastern Finland in 19972000. In each of four pens (9751300 m2) eight suckler cows were fed in winter from 1995 in the case of the first two pens and from 1996 in the remaining two. The suckler cows usually stayed in the front part of the feedlot. Therefore the nutrient loading was also the highest in this part of the lot. When the pens had been used for 12 winters, the mean contents of PAAAc, NH 4-N and NO 3-N in the surface soil (05 cm)were 14,73 and 3.0 mg l1 respectively, compared to only 3.0, 4.2 and 0.06 mg l1 in the control forested area. In the front part of a 1-m-deep soil layer, the mean amounts of NH 4-N, and NO 3-N were 410 and 28 kg ha1 respectively after 12 years of use of the feedlot. In percolation water, too, the mean concentrations of total phosphorus and total nitrogen were high in the front part: 1.7 28 and 2101400 mg l1 respectively. The minimum requirement is cleaning of the dung, and even then loading may be substantial.;