Plant nutrients and alternative fertilizers

Biogas digestate and wood ash as fertiliser replacements:  effects on crop and soil -  Sigrun Dahlin

Society needs to decrease generation of wastes by reuse of resources to develop a sustainable, low carbon and resource-efficient economy incl. agriculture. When such materials are used as fertiliser replacements or a soil amendments, their effects on crops in terms of yield size and quality are important but also their effects on soils. I will present examples of effects of mainly biogas digestates and wood ashes on crop and soil from past projects and also briefly present a new project which aims to provide enhanced risk assessment and a tool to estimate safe application rates on farms.

Wheat grown with recycled fertilizers in the north within the project Boost Nordic Biogas – Cecilia Palmborg

Two experiments with spring wheat were conducted in Umeå 2023. Digestate and products made from digestate were tested as fertilizers. Inorganic nitrogen in the fertilizers were a good estimate of the fertilizer value, but in liquid digestate made from household waste all nitrogen seemed plant available.

Alternative organic nutrient sources in Swedish agriculture – Elsa Lagerquist

To close nutrient loops and thereby achieve a circular economy, reduce the reliance on imported mineral fertilisers and avoid environmental pollution, organic waste products is an interesting optional nutrient source in agriculture. In the study to be presented, we investigate the amounts and composition of current and potentially future sources of organic waste products in Sweden, in amounts as well as from their nutritional perspective. Special focus is on organic farming, which has more strict standards on sources and contamination levels.