COMPOSTED SEWAGE SLUDGE AND SOIL AMENDMENT FOR GREENHOUSE AND WOODY ORNAMENTAL CROPS

From the studies reported here, using lime dewatered sewage sludge, the following recommendations are made.

In nursery production one application of compost at 224 mt/ha in a sandy loam soil during a 4 year period is optimum for the production of two crops of deciduous tree seedlings.
Seedling growth was poorer at either a lower or greater rate of sludge application.

Potting mixtures for flowering pot plants or woody ornamental plants should not contain more than 1/3 by volume of composted sewage sludge.
The acidity may rise to pH 6.8 to 7.2 in 2 to 3 months, even with peat and/or milled pine bark in the medium which is a suitable level for many greenhouse crops.
For crops requiring a more acid medium, it should be amended with a mixture of both wettable S and of granular S at 3 kg/m².

Annual bedding plants may be grown in media of 1/3 by volume of compost.
The medium contains an adequate mineral nutrient level so that fertilizer need not be applied until 3 weeks after planting to promote normal growth.

Nutrient Film Technique and Substrates, XXI IHC

C.B. Link, F.R. Gouin, J.B. Shanks

https://doi.org/10.17660/ActaHortic.1983.133.22