Applications of seaweed extracts in agriculture: An Australian perspective

Society depends on food production. However, agricultural productivity is greatly challenged by extreme climate events and volatility. Seaweed extracts (SWE) have a key role in food production and their use is central to improving agricultural productivity by increasing crop tolerance to stress, improving the efficiency of plant nutrient use, and by contributing to sustainable farm practices. The benefits of SWE to crops have previously been reviewed in the context of the northern hemisphere, but not since 2015 in Australia – specific to its crops and unique stressors. This review is focused on the scientific progress since 2015 and insights from Australian research related to: (i) SWE-stimulated plant responses, (ii) field research on SWE, (iii) optimising the use of SWE in agriculture. The review considers the effects of SWE (made from Durvillaea potatorum and Ascophyllum nodosum) in the field, across crops, seasons, regions, and farming systems in Australia, and research conducted in the laboratory under controlled conditions on model and crop plants at the molecular, cellular, and physiological levels. The results from the review highlight the role of SWE in plant priming responses in laboratory experiments and its association with improved plant tolerance in the field. The review discusses the field effects related to production and fruit quality. The uniqueness of the Australian research is the inclusion of the same SWE in laboratory and field research, and the characterisation of plant responses under challenged and un-challenged conditions. This information provides deeper insights into the actions of SWE and enables growers and agronomists to optimize their field application in Australian agriculture.