Compost: the effect on nutrients, soil health and crop quantity and quality

Summary

The primary scope of this review is to provide evidence for the effects of compost as distinct from the effects of fresh or stored manure. It is intended to help advisers and farmers identify when the use of compost or a composting process is appropriate. This review does not address the detailed issues surrounding the various production of compost but includes some basic information with particular respect to on-farm composting operations.
The differences between well-made compost and semi compost (single turned) that may be revealed by this review could inform decisions about the approach taken to composting in an on-farm situation.
The specific issues addressed by the review will include:
•The different types of compost available to producers, and their qualities and properties.
•The role of composts in disease suppression and, where shown, the mechanism for any effects.
•The direct and indirect effects on crop yields.
•Detectable and measurable effects on crop quality (an appropriate definition of quality will be required).
•The effects of compost applications on soil biology and organic matter levels, and the implications for carbon sequestration.
•The most appropriate situations for the use of compost as opposed to fresh manure.
•This has a particular relevance in the production of ready to eat horticultural crops
This review does cover the use of bulky organic materials generated by fermentation or anaerobic types of process such as biogas generation, the use of compost teas and the use of compost(s) in growing media for plant raising and production.