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N and P leaching and microbial contamination from intensively managed pasture and cut sward on sandy soil in Finland
The aim of this study was to find out if nutrient leaching from grassland represents a threat to groundwater in areas that are subject to freezing and extensive snow cover. The effects of grazing and cutting on groundwater quality were compared using field lysimeters during a 3-year experiment at No...
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Published in: | Agriculture, ecosystems & environment ecosystems & environment, 2004-12, Vol.104 (3), p.621-630 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The aim of this study was to find out if nutrient leaching from grassland represents a threat to groundwater in areas that are subject to freezing and extensive snow cover. The effects of grazing and cutting on groundwater quality were compared using field lysimeters during a 3-year experiment at North Savo Research Station (63°10′N, 27°18′E), Finland. One-third of the annual precipitation at this site (578
mm per year) falls as snow. Snowmelt produces over 100
mm of water flow and there is a substantial risk of nutrient leaching. The soil at the site was a medium textured Dystric Regosol, consisting mainly of fine sand. The lysimeters used in this study were 100
m
2 and 1.8
m deep, suitable for grazing studies. The watering point for cows was located on one of the lysimeters. The area was fertilized with N at 220
kg
ha
−1 per year. After two summers of grazing and cutting the area was treated with glyphosate and in the following spring it was ploughed and resown to grass. The NO
3-N concentrations were low and there were no differences among treatments during the first 2 years of the trial. After glyphosate application nitrate leaching increased and the average concentrations of NO
3-N from cut, grazed and watering point lysimeters were 3.4, 10.2 and 21.8
mg
l
−1, respectively. The amounts of leached NO
3-N after glyphosate treatment were 10, 43 and 139
kg
ha
−1 per year, respectively. Phosphorus leaching was negligible. In the first year the numbers of heterotrophic micro-organisms in leachate from grazed and cut lysimeters were similar. In the second year leachate from grazed lysimeters contained more heterotrophic micro-organisms than that from cut plots (geometric means 44
000 and 4600
CFU
ml
−1, respectively). Moreover, the leachate from the grazed plots and the watering point occasionally contained low numbers of enteric micro-organisms, faecal coliforms and
tyrobutyricum clostridia. The study indicated that cutting and grazing did not represent a risk to groundwater quality during grass cover years, but renovation of pasture caused a significant N leaching to groundwater. |
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ISSN: | 0167-8809 1873-2305 |
DOI: | 10.1016/j.agee.2003.12.015 |