COMPOSTING SEWAGE SLUDGE WASTES IN RELATION TO THEIR SUITABILITY FOR USE AS FERTILIZER MATERIALS FOR VEGETABLE CROP PRODUCTION

There is increasing interest in the use of sewage sludge composts for crop production, but few quantitative data are available comparing effects of these materials on crop growth with conventional mineral fertilizers.
Here, a systematically designed experiment is described where combinations of sewage sludge compost, digested or raw sludge and ammonium nitrate were supplied to summer cabbage and autumn sown onions grown in succession on the same field site.
Sewage sludges and compost increased the yield of both crops, however the magnitude of the effect was larger than could be explained by the N availability characteristics of the materials alone.
These responses are discussed in relation to effects of sludge and compost application on soil physical conditions.
Yield response of cabbage to ammonium nitrate was increased when a similar rate of N was supplied as sewage sludge or sludge compost.

Therefore, organic matter application improved the efficiency of mineral fertilizer use.
The response of onions to applied sludge and sludge compost indicated that yield was limited mainly by soil physical properties whilst increasing N availability by mineral N application had no effect on crop growth.

International Symposium on Compost Recycling of Wastes

S. R. Smith, Jeremy E. Hall, P. Hadley

https://doi.org/10.17660/ActaHortic.1992.302.19