In some good news for sustainable agriculture, work aided by the APPF with Seasol® has shown the positive effect of seaweed extracts on nitrogen use and photosynthesis.

Future agricultural systems will require sustainable management practices, including the use of fertilisers. We know the application of nitrogen fertiliser enhances yield but it can also lead to environmental damage and greenhouse gas emissions. Improving the nitrogen use efficiency of crops could alleviate the negative impact of nitrogen fertilisation without yield loss, and that’s where seaweed comes into the picture. 

Seasol seaweed extract is an organic liquid fertiliser classified as a plant biostimulant that is known to have a positive effect on plant productivity. The Director for R&D at Seasol International, Dr Tony Arioli, has been working with the APPF and CSIRO to assess the effect of Seasol application on nitrogen uptake and efficiency in bread wheat (Triticum aestivum). Dr Arioli said, “the research aimed to determine whether Seasol could be added as a supplement to nitrogen fertilisation and potentially reduce the quantity of nitrogen applied to agricultural systems”. 

The research was conducted in glasshouse pot-based experiments at the APPF’s controlled environment facilities located at CSIRO in Canberra. The effect of Seasol was assessed at varying nitrogen application rates corresponding to those used in Australian agricultural systems. Researchers found the addition of Seasol was associated with a positive impact on plant growth with less nitrogen, and lower nitrogen uptake and lower plant nitrogen content. Furthermore, a positive effect was found on plant photosynthesis, which plants use to convert light into chemical energy. Senior Research Scientist on the project Dr Gonzalo Estavillo said, “the results are significant because nitrogen is a major constituent of the plant photosynthetic machinery, and these efficiencies were achieved despite Seasol plants containing less nitrogen overall”. 

While more work is needed to understand the mechanism leading to these positive effects of seaweed extract on plant performance and carbon assimilation, the research does support looking into the potential application of seaweed extracts in improving nutrient use and developing sustainable agricultural practices. This knowledge could then be applied to improve field crop growth. 

The APPF is continuing its collaboration with Seasol to better understand the effect Seasol has on photosynthesis. It is hoped this type of science will lead to the discovery of new plant mechanisms and assist sustainable and regenerative agriculture.