Book of Abstracts
11th IFOAM Scientific Conference
11-15 August 1996, Copenhagen, Denmark
1Dept. of Soil Science, Danish Institute of Plant and Soil Science, P.O. Box 23, DK-8830 Tjele, Denmark. 2The Federation of Danish Pig Producers and Slaughterhouses, The National Committee for Pig Breeding, Health and Production, Axeltorv 3, DK-1609 Copenhagen V, Denmark
The pig production from organic farms in Denmark has until now been very low. In order to improve the future situation The National Committee for Pig Breeding, Health and Production initiated a project where key problems in organic pig production were identified, including nutrient balances. The objective of the present work was to evaluate how long term soil fertility can be satisfactory maintained on organic pig producing farms.
Nutrient balances (N, P and K) were calculated for different fictive organic pig producing farms with different livestock densities, ranging from 0.7 to 1.7 livestock units (LU) per ha. These farms imported from 35-65% of total fodder consumption. Nutrient balances at field level showed that a livestock density of 0.8 LU/ha was sufficient to fulfill plant nutrient demands, at lower livestock densities potassium appeared to be the most limiting nutrient. At farm level nutrient balances showed increasing nutrient surplus at increasing livestock density due to increasing fodder import. At 0.8 LU/ha the nutrient surplus was 50-60 kg N, 10 kg P and 25-30 kg K/ha. It was concluded that self sufficiency regarding organic grown fodder implies the use of a significant area for nitrogen assimilation in crops for green manuring, resulting in a production system with only 0.5-0.6 LU/ha.
Experience with organic pig production is very limited at this stage. Therefore, the present calculations based on fictive farms should be followed by real farm studies. Especially nutrient losses from outdoor pigs and the use of forage crops in pig fodder should be investigated.