In agriculture there is an increasing interest in the use of compost. Also in greenhouse cultures, were there is an active search for substitutes of peat and rockwool. The competition around the use of renewable sources is therefore also increasing. Bart Vandecasteele of ILVO explained their research in the BioCASH project. The research reveals that green compost can first be used to replace peat in growing media, after which it can contribute stable carbon to arable fields in the form of spent growing media. The use of green compost also has economic advantages for the growers of greenhouse vegetables.
The competition for substrates and replacement of peat is also resulting in new challenges. New materials like wood fibres, biochar and miscanthus have other characteristics then for example peat. So extensive research is needed, for example about stability, nutrient content. This transition from peat based substrates towards peat free substrates means also changing and adaptation of the cultivation strategy.
ILVO carried out different case studies, The spent horticultural substrates were used to produce compost and were compared with greencompost. The substrates were also used to make biochar, which were compared with woodbased biochars. The substrates were analyzed on organic carbon, inorganic carbon, the C over P content. Conclusion of the project is that spent horticultural substrates are a very good carbon rich source to improve soils. This means that using biochar and greencompost in cascade avoids the competition for this biomass. Here the link to the powerpoint.
To get a picture of the subject, ILVO made a nice video.