Agriculture has a nitrogen problem, both in terms of the environmental and monetary costs of fertilisers, and the pollution risk when nitrogen application is not well targeted. Green manures – nitrogen fixing crops that are then ploughed into the soil – are a conventional solution to this issue in organic agricultural systems, but neither the concentrations or timing of nitrogen application are well matched to crop needs.
In a recently completed project, a range of rapidly growing perennials, including alder and willow were harvested and processed, and then applied to horticultural land the following season, and the results were monitored.
The project report is available here: https://www.dyfibiosphere.wales/perennial-green-manures
and the underpinning journal paper here: https://link.springer.com/article/10.1007/s10705-022-10253-x.
