Effects of Zelp, an NZ Kelp product, on pasture germination and production compared to a processed nutrient solution : A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science at Lincoln University

Abstract

Regenerative agriculture (RA) has be every more popular due to the consumers change towards more sustainable products. One of RA agriculture practice is to turn away from processed nutrient fertiliser and use organic fertiliser. One organic fertiliser that has been use is seaweed extract based. Seaweed extracts are suggested to improve soil health, plant health & disease resistance and to increase germination. This is said to be through, natural plant growth hormones, micronutrients, complex polysaccharides (sugars), antibacterial/antiviral properties, chelating agents and alginates. However, due to the very limited research conducted especially using common pastures in New Zealand pastoral systems it is difficult to understand if the seaweed extracts do what they suggest. Four common pasture species were experimented using Zelp an seaweed extract plant promotor from NZ Kelp and a nutrient solution which contains equivalent amounts of nutrients. There were 2 different experiments conducted, germination test and a pot trial where Zelp and the nutrient solution were compared to each other. There were two separate germination test, one using Zelp and the other using the nutrient solution. Both tests were conducted over 15 days in an incubator set to 20C. The pot trial was completed for 3.5 months under glasshouse conditions. At the competition of the pot trial shoot and root yields measurements were completed. The key findings from the two-germination tests completed was that lucerne seed had a greater germination % for Zelp than the nutrient solution, with a 10% increase in total mean germination. Subterranean clover and Italian ryegrass had a significant greater germination % to the control and commercially recommend rate of Zelp (2 kg/ha) than the two higher rates of Zelp (4, and 8 Kg/ha). For the pot trial there were four key findings; both Italian ryegrass and cocksfoot had an increase in shoot fresh weight when using the nutrient solution compared to Zelp. Italian ryegrass also had a greater response in the shoots dry weight using nutrient solution. The final key finding for the pot trial was that Italian ryegrass shoots: roots ratio was significantly greater when using Zelp. Only lucerne had a greater response to Zelp compared to the nutrient solution. This is an interesting result, as it was expected that if Zelp had positive effects on one species that it would have positive effects on all of the species tested. This therefore, indicates that the effect of Zelp on seed germination % is species specific, or that the mechanism involved causing this result is species specific. Nutrient solution had greater yields in the grasses. This could be because of grasses requiring nitrogen to increase growth unlike the legumes which fix atmospheric nitrogen. Another possibility is that the nitrogen and nutrients in the nutrient solution was more readily available compared to the organic nitrogen in Kelp which is the nutrients found in Zelp. Based on these findings further research is required to fully understand Zelp’s contribution to New Zealand’s pastoral systems and if seaweed based fertiliser can be compared to the processed nutrients.