The Theoretical Potential of Hondsrug Glacial Rock Dust as Soil Remediator in The Netherlands
Niels Christian Olfert
Agriculture in the Netherlands is a major source of ammonia (NH3) emissions. Deposited nitrogen levels in the Netherlands reached 2-3 times their critical value at the start of 2020. Excess nitrogen in soil may cause declines in biodiversity and ecosystemic disequilibrium. This may lead to acidic and decalcified soils that are less capable of retaining nutrients. The mineral fines in rock dust are proven agents in soil remediation and remineralization. Glacial moraine deposits are a branded source of rock dust and are contained in the glacial till of the “Hondsrug” area, a boulder clay ridge in the northeastern Netherlands. Formerly, erratic rocks from this boulder clay served various practical purposes. The existing apparent inutility of these erratic rocks motivates us to review their potential as rock dust. Lack of chemical analyses on the in situ erratic rocks resorts to an evaluation of their inferred Fennoscandian source rocks which are of igneous and sedimentary lithology. The chemical composition of these inferred source rocks is compared with that of proven rock dust suppliers. It is concluded that even though there are compositional parallels between the rock dust, the Hondsrug area glacial till is comparatively decalcified and mineralogically of limited benefit. Moreover, exceptional magnitudes of erratic rocks are scarcely encountered while at the same time, the bulk is preserved as geological heritage. Despite the adversities, it could be chosen to commence trials with crushing idle erratic rocks in the Hondsrug area whenever this may be assessed as a useful supplement.