Barley Can Utilise Algal Feriliser to Maintain Yield and Malt Quality Compared to Mineral Fertiliser

Abstract

Background and AimsMineral fertilisers are essential for global crop productivity. However, their use is unsustainable due to high energy costs from sourcing and processing them, and nitrous oxide emissions after their application. An alternative proposition is the use of microalgal biomass as a nutrient source for fertilisation. To date, there is limited data on how the productivity of barley grown with microalgae would compare to barley grown with mineral fertilisers. Furthermore, the impact of the fertiliser source on suitability of grain for malting, one of barleys main end uses, should be considered. MethodsWe quantified the phenology, reflectance indices and yield components (including yield itself) of barley cv. Laureate grown with either Chlorella vulgaris powder or mineral fertiliser in three glasshouse trials in different soils, to assess the robustness of our findings under soil-to-soil variation. We extended this approach to carry out a field trial from which we malted the grain collected at the end of the season and quantified malt quality. ResultsWe hypothesised that there would be no statistically significant difference in plant performance when grown with microalgae or mineral fertiliser when nitrogen addition was equal. Both glasshouse trials and a field trial showed that plants grown with microalgae and mineral fertiliser do not significantly differ in any yield component, yield itself, or measure of malt quality except total malt nitrogen. ConclusionsSupplying the same amount of nitrogen to plants via microalgal biomass instead of mineral fertiliser produced barley with the same yield and malt quality as plants grown with mineral fertiliser.