Enhanced Retention and Clean Dewatering of Nutrients in a Slow-Release Organic Silicon Fertiliser

Abstract

The development of sustainable fertilisers prepared from local and renewable resources is an increasingly urgent challenge faced by agricultural and food sectors globally. This challenge is complicated by the need to deliver nutrients directly to crops with minimal environmental impact. Herein, we explore the characteristics of an organic silicon fertiliser prepared by treatment of digestate using potassium silicate and calcium chloride. The results show the fertiliser has a porous structure in which organic matter and nutrients become embedded, thus enabling slow release of nutrients. The silicon is present in a bio-available form and is shown to enable clean dewatering of aqueous organic mixtures. Crop trials demonstrate similar or increased crop yields compared with mineral and organic alternatives. The findings suggest these fertilisers could enable a cost-effective end-use for digestate and have profound implications for the achievement of net zero policies.

Keywords: Digestate, sustainable fertilisers, mineral fertilisers, organic fertilisers, silicon fertilisers, potassium silicate, dewatering, bio-available silicon, soil conditioners, nutrient retention