ABSTRACT
Manure management in organic farming Peter Sørensen, Department of Agroecology, Aarhus University, Denmark; Luca Bechini, University of Milan, Italy; and Lars Stoumann Jensen, University of Copenhagen, Denmark
1 Introduction
2 Manure composition and properties in different livestock systems
3 Manure storage and treatment
4 Manure field application methods
5 Turnover and availability of manure N in soil
6 Utilization of P, K and S in manures
7 Plant-based manures (green manures)
8 Future trends and conclusion
9 Where to look for further information
10 References
In all agricultural systems, nutrients removed with harvested crops or lost from the soil need to be replaced by new inputs of nutrients, at least in the long term, in order to maintain and improve soil fertility and sustain crop production. In most organic farming systems, animal manures are the most important source of both macro-and micronutrients. Nitrogen (N) is also supplied via N-fixing crops and a variable amount by atmospheric deposition, but manures are usually an important source of N which is normally the most yield-limiting nutrient in non-N-fixing crops. At the same time, manure N is the most challenging nutrient to manage and utilize efficiently, as it can be lost in a number of processes, both in gaseous forms and by leaching and runoff. Therefore, a first priority in manure management should be to focus on reducing N losses in all steps of the manure handling chain. Secondly, manure management should aim to sustain or improve soil fertility, to secure a long-term supply of other nutrients in each agricultural field on the farm.
