Solid farm manure and compost

One of the principal objectives of organic farming is to control the use of nutrients, and, as far as possible, avoid losses. Nutrients are an important resource, and are often a limiting factor in production. At the same time nutrient losses can damage the surrounding environment.

In organic farming there is considerable interest in solid manure and compost, not least for animal welfare reasons. In comparison to slurry, only few studies have been made of carbon (C) and nitrogen (N) losses, and nutrient metabolism in deep litter.

The use of straw bedding systems, and the composting of deep litter and solid manure, is expected to raise ammonia losses, compared with the conventional anaerobic handling of slurry. Nitrogen losses associated with composting can vary from 20 to 50%, but there is little information on the corresponding losses from sheds or storage pits, or the nitrogen fertiliser value of aerobically treated deep litter and compost.

This project aims to measure the losses of carbon and nitrogen, and the metabolism of these nutrients in deep litter, storage heaps, and fields, with a view to improving soil fertility and the fertiliser value of solid manure. It incorporates the following elements:

• Investigation of the basic processes in nutrient metabolism, and quantification of nutrient losses in association with various typical handling treatments and storage systems for deep litter and compost on organic farms
  
  
• Development of practical methods to combine a high degree of aerobic metabolism with a minimal loss of nitrogen
  
  
• Investigation of the availability to plants and losses of nitrogen applied in different types of manure in selected rotations. This includes studies of the timing of nitrogen release in relation to plant requirements.
  

Summary
Publications


Project title
I.1 Solid stable manure and compost

Project leader
Svend G. Sommer
Danish Institute of Agricultural Science,
Department of Agricultural Engineering,
Research Centre Bygholm, P.O. Box 536,
DK 8700 Horsens
Tel: +45 7560 2211, Fax: +45 75624880,
E-mail: SvendG.Sommer@agrsci.dk

Project participants:
Hans Benny Rom, Ib Sillebak Kristensen, Ingrid K. Thomsen, Danish Institute of Agricultural Science
Kaj Henriksen and Per Møldrup, Laboratory for Environmental Technology, Aalborg University.