In the quest for sustainable agriculture, researchers are turning to bio-based fertilizers (BBFs) as a promising alternative to traditional phosphate fertilizers, which rely on finite mineral resources. A recent study published in the journal *Luonnonvarat, Ympäristö ja Kestävän Kehityksen* (Resources, Environment and Sustainability) sheds light on the environmental impacts of these BBFs, particularly their potential to mobilize phosphorus (P) in soils with varying properties.
Led by Kari Ylivainio from the Natural Resources Institute Finland, the study aimed to assess P losses promoted by different BBFs and triple superphosphate (TSP) in soils from Finland, Germany, and Spain. The team applied 11 BBFs, derived from a range of raw materials and production technologies, to soils with different pH levels and P retention capacities. After a three-week incubation period, they simulated rain to observe P mobilization.
The results revealed significant variations in dissolved reactive P (DRP) and molybdate-unreactive P (MU-P) concentrations in percolation water, depending on soil properties and P sources. “Soil P tests that extract easily soluble P fractions predicted DRP concentrations in percolation water better than those extracting less soluble P fractions,” Ylivainio noted. This finding underscores the importance of understanding soil properties in managing P losses.
The study found that TSP, digested and composted pig slurry, and mineral/precipitate BBFs led to the greatest DRP mobilization in acidic and calcareous soils. In contrast, organic BBFs containing tricalcium/hydroxyapatite and ash-based ones resulted in the least P mobilization across all soil types. Granulation of BBFs effectively reduced P losses among BBFs with similar P speciation, offering improved handling and P utilization.
The implications of this research are significant for the energy and agricultural sectors. As the world moves towards a circular economy, BBFs present a sustainable solution for P supply. However, minimizing P losses requires a nuanced understanding of both soil and BBF properties. “Compared with soluble mineral P fertilizers, BBFs offer a means to reduce P losses,” Ylivainio explained. “But to fully harness their potential, we need to consider the interplay between soil characteristics and BBF composition.”
This study paves the way for future developments in the field, emphasizing the need for tailored approaches to fertilizer application based on specific soil conditions. As the energy sector increasingly focuses on sustainability, insights from this research can guide the development of more efficient and environmentally friendly agricultural practices. By leveraging the unique properties of BBFs, we can move closer to a sustainable future for agriculture and beyond.