Elimination behavior and soil mineral nitrogen load in an organic system with lactating sows – comparing pasture-based systems with and without access to poplar (Populus sp.) trees

ABSTRACT

Innovative strategies in free-range pig production are needed to improve the environmental performance of the system. Based on previous studies, inclusion of trees was hypothesized to improve the system’s nitrogen efficiency. We investigated sow elimination behavior, feces load, and localization as well as soil mineral nitrogen load in pasture-based individual paddocks with and without access to two rows of poplar (Populus sp.) trees. In contrast to what was expected, sows showed no preference for eliminating in the zone with poplars but clearly avoided defecating near the hut, feed, and water. Soil mineral nitrogen load showed a heterogeneous pattern as also found in previous studies. In comparison to grass, our results indicated that the poplars had an increased winter uptake of nitrate from deeper soil layers.

KEYWORDS:

• Organic farming
• free-range pigs
• lactating sows
• poplar trees
• elimination behavior
• soil inorganic nitrogen

Acknowledgments

The authors would like to thank the commercial organic pig producer and his employees for making this experiment possible and for helping us throughout the almost 1-year study period. We also very much appreciate the assistance of research technicians Kristine Riis Hansen and Orla Nielsen for carrying out the data collection. The experiment is part of the pECOSYSTEM project (Pig Production in Eco-efficient Organic Systems). pECOSYSTEM is part of the Organic RDD 2 program, coordinated by ICROFS (International Centre for Research in Organic Food Systems), Aarhus University, Denmark.

Additional information

Funding

This work was partly funded from GUDP (Green Development and Demonstration program), under the Danish Ministry of Food, Agriculture and Fisheries.