As a rule, highly bio-diverse vegetation develops mostly in low-fertility soils. On former agricultural land, in which phosphorus availability levels are high because of years of fertilisation, the soil nutrient fertility hampers the development of high bio-diversity. The excavation of phosphorus-rich soil (earth removal) is not only a costly measure, but not always possible, due to local cultural-historical and/or archaeological considerations, or because of the negative impact on local water management. Alternatives to excavation are therefore important.
This research determines the soil types and soil moisture levels for which the application of drinking water sludge can effectively lower phosphorus availability in former agricultural lands and existing nature areas, thus favouring nature development. This application can offer a more economical alternative to excavation of these high-phosphorus soils. A second objective is the development of a machine which, with minimal ground pressure, can inject a good mixture and constant dose of the drinking water sludge, regardless of the sludge’s consistency or the soil’s type.
At the conclusion of the project an understanding is acquired of the effects of drinking water sludge on soil chemistry and vegetation development in high-phosphorus soils of different compositions and moisture conditions. This results in a matrix of application possibilities and tailored advice. Moreover, the specifications are defined for a machine (turf injector) which can effectively inject the drinking water sludge. Through the active participation of land managers in this project, wide support will have developed for the application of drinking water sludge.