FAQs - The basic science

Recently, when we have been telling people about our project, we have been getting the same responses back. Therefore, Georgia kindly compiled the following:

1. What is vermicomposting and vermicompost leachate?

Vermicomposting, also known as wormfarming, is a waste management technique using worms to transform organic waste into biologically-rich manure (Carlos et al, 2008). Vermicompost leachate (VCL), or ‘worm tea’, is the liquid released by earthworms (Kandari et al, 2011). VCL is said to stimulate plant nutrient uptake and support plant development due to the humic acids, fluvic acids and plant growth regulators it contains. (Carlos et al, 2008).

2. What is the aim of your experiment?

Our experiment aims to determine if VCL is more effective fertiliser compared to an inorganic equivalent, which, in our case, is Aquasol.  

3. Why are you using aquasol?

We chose to use aquasol as it is a common purely synthetic fertiliser, which means it has no biological component. Other common commercial fertilisers such as Seasol and Nitrosol were not chosen, as they are organically based (from seaweed extract and blood and bone respectively) have growth promoters added (Zodape, 2001). 

4. Why are you growing lettuce and soybean plants?

As nitrogen is the key element in most fertilisers, we chose test the effectiveness of VCL and Aquasol on a nitrogen fixing plant (soybean) as well as a non-nitrogen fixer (lettuce) that is common in urban gardens. These plants were also chosen due to their rapid growth to suit our study’s limited timeframe.

5. Why are you growing the plants in sand?

Soil structure has a great affect on plant growth as it influences the movement of water, air and nutrients to plants (Charman and Murphey, 1992). As we did not want any differences in soil structure between pots, sand is being used, as it has very low inherit biological activity, and little to no structure.

6. What is the difference between normal leachate and autoclaved leachate?

As vermicomposting is an organic process, VCL contains both a biological component (micro-organisms) and a chemical component. Autoclaving is a process of sterilising, or killing the biological component that would be present. By comparing plants grown with normal leachate and autoclaved leachate, this will show us if VCL’s fertilising ability is due to its inherit biological activity, or if it is the chemical composition alone, that makes it a viable fertiliser.

7. Why are some of the plants being only given water?

As with any scientific investigation, there are control plants being grown, that are only receiving water daily. These plants will show the growth of plants in absence of fertiliser. 

If you have any more questions, please keep them coming!

Watering the lettuces last saturday

References

• Carlos, G, Dendooven, L, Antonio, G, 2008, Vermicomposting leachate (worm tea) as liquid fertiliser for maize (Zea mays L.), Academic Journals Inc, USA.
• Kandari, L, Kulkarni, M, Staden, J, 2011, Vermicompost leachate improves seedling emergence and vigour of aged seeds of commercially grown Eucalyptus species, Southern Forest: Journal of Forest Science, vol 77, 2, 534-535.
• Zodape, S, 2001, ‘Seaweeds as a biofertiliser’, Journal of Scientific & Industrial Research Volume, vol. 60, 5, 378-382.
• Charman, P, Murphey, B, 1992, Soils their properties and management. Soil Conservation Commission of NSW. Sydney University Press. Chapter 16. Soils and farming practice. Harte, A.J.