|Bergstrom, Lars - Swedish University Of Agricultural Sciences|
|Aronsson, Helena - Swedish University Of Agricultural Sciences|
|Geranmayeh, Pia - Swedish University Of Agricultural Sciences|
|Riddle, Matthew - Swedish University Of Agricultural Sciences|
|Kirchmann, Holger - Swedish University Of Agricultural Sciences|
Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 6/12/2016
Publication Date: 11/9/2016
Citation: Bergstrom, L., Aronsson, H., Geranmayeh, P., Riddle, M., Kirchmann, H., Bolster, C.H. 2016. Mitigation measures to reduce losses of phosphorus during the non-cropping period - a northern European perspective. American Society of Agronomy Meetings. 1.
Technical Abstract: Degradation of natural waters by phosphorus (P) due to agricultural activities has been a problem in several countries for many years. Accordingly, mitigation measures to minimize this issue have been developed and used with varying success. Non-point source P from agricultural fields is one of the most important types of losses to reduce as this often contributes more than 50% of total anthropogenic P loads to surface and ground waters. In Sweden, a large phosphorus program involving 24 different projects was started in 2008, with focus on testing different best management practices (BMPs) to reduce P losses from agricultural soils. Precipitation surplus and snowmelt periods during winter result in these losses occurring mainly during the non-cropping season. Some of the BMPs tested were: application schemes for animal manure, structure liming in clay soils, catch crops and constructed wetlands. These trials were carried out in tile-drained field plots and lysimeters. Application of pig slurry to the soil surface under wet conditions in late autumn increased P leaching in a clay soil. In another study, it was shown that incorporation of the slurry in a clay soil reduced total P (TP) leaching by 50% compared to surface application. It should be noted that application of manure on frozen soil is not allowed in Sweden. Structure liming reduced TP loads by up to 55%, whereas P leaching was not reduced by catch crops. In contrast, leaching increased 7-fold in a clay soil when catch crops were used, due to plant destruction during freezing/thawing events. A constructed wetland reduced TP loads by 36% over a year, but high-flow periods during winter could be a problem due to reduced sedimentation. The many BMPs tested in this program showed that P losses can be reduced substantially during the non-cropping season, but some have their limitations.