PRODUCTION OF COMPOST IN A HEAT COMPOSTING PLANT AND TEST OF COMPOST MIXTURES AS GROWING MEDIA FOR GREENHOUSE CULTURES.

L. Jespersen, J. Willumsen
Two different raw material mixtures based upon agricultural waste products were formulated according to the chemical and physical qualities of each waste product and pre-composted in a heat composting plant. Afterwards the composts were composted in windrows. Based upon the results of chemical analyses, the two cured and screened composts were mixed with peat in two different ratios producing 4 test media. The compost-peat mixtures were tested as horticultural substrates in a greenhouse using tomato cultivated in growing bags and Exacum affine grown as pot plants on ebb-flood benches with two different fertilization strategies. The results indicate that it is possible to produce composts of such a uniform and suitable quality as concerns chemical and physical properties that compost can replace 20 – 40 volume % of the peat and most of the fertilizers in peat substrates for horticultural crops. It seems possible to obtain equal or better yield and quality and perhaps earlier flowering of Exacum affine by growing in compost mixtures with a considerably higher content of available nutrients than in the peat substrates normally used by professional greenhouse growers. During the first part of the growing period it may be an advantage to reduce the concentration of nutrients in the irrigation water, dependent on the concentration of available nutrients in the compost mixture.
Jespersen, L. and Willumsen, J. (1993). PRODUCTION OF COMPOST IN A HEAT COMPOSTING PLANT AND TEST OF COMPOST MIXTURES AS GROWING MEDIA FOR GREENHOUSE CULTURES.. Acta Hortic. 342, 127-142
DOI: 10.17660/ActaHortic.1993.342.15
https://doi.org/10.17660/ActaHortic.1993.342.15

Acta Horticulturae