Speaker
Description
Greenlandic glacial rock flour (GRF) is a potential source of silicate minerals for CO2 uptake via enhanced weathering which would mitigate the need for energy-intensive crushing due to the naturally fine grain size (D50: 2.6 microns) of this material. The chemical makeup of this material also indicates that it may be a good source of plant nutrients, including K in particular. Results thus far have indicated that GRF can successfully improve plant growth, but the extent of its impact appears to be dependent on the initial nutrient status of the soil. Whereas in maize trials conducted on nutrient-poor soils in Ghana we have observed a 48% increase in total grain yield across 5 consecutive growing seasons after a one-time application of 50 t/ha of GRF, results in Denmark have been mixed. The same application rate of GRF increased silage maize yields by 24% and potato yields by 19% in the year of application when applied to a certified organic farm, but this increase did not persist in the following growing seasons. When applied to a conventionally managed farm with high soil K, no effect of GRF was observed on barley yields in the year of application. This year’s installation of a network of 11 new field trials will allow for improved understanding of how yield response, mineral weathering rates, and the associated uptake of CO2 vary as a function of environmental conditions and GRF application rates.
