E-Thesis 455 views 75 downloads
Social-ecological experiment on the effects of organic fertilisers and biochar on onion yield and soil macroinvertebrates / ROBBIE JAMES
Swansea University Author: ROBBIE JAMES
Abstract
Research into the effects of conventional agricultural methods identifies them as primary drivers of biodiversity loss and climate change worldwide. Transition from conventional methods to agroecological management requires collaboration between groups with different knowledge bases and practical sk...
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Swansea, Wales, UK
2023
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| Institution: | Swansea University |
| Degree level: | Master of Research |
| Degree name: | MRes |
| Supervisor: | Roberts, Laura., Wells, Konstans. and Börger, Luca. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa63719 |
| Abstract: |
Research into the effects of conventional agricultural methods identifies them as primary drivers of biodiversity loss and climate change worldwide. Transition from conventional methods to agroecological management requires collaboration between groups with different knowledge bases and practical skillsets to overcome the barriers farmers experience in adopting these methods. Several frameworks have arisen to enable this collaborative work. This experiment applied a framework for social-ecological (SE) experiments by Gaba & Bretagnolle (2020) at a reduced scale to co-design a field experiment with local farmers in Swansea, Wales. This trial aimed to solve the communicated problem of poor field productivity whilst tailoring the materials and methods to the socioeconomic constraints of the farmers so outcomes were of practical use long-term. Treatments were green waste compost with and without biochar, partly composted chicken litter with biochar, composted chicken manure pellets without biochar, a control with biochar only and another with no treatment. Onion yield was the chosen social outcome as these were due to be sown in the problem field, and changes to soil macroinvertebrate community diversity was the ecological outcome due to their importance for providing ecosystem services like nutrient cycling. Results showed significant negative effects of chicken litter with biochar on yield and total invertebrate density (mainly earthworms and potworms), which was likely explained by ammonium-N toxicity. Biochar had negative effects on invertebrate diversity likely due to an increase in pH affecting the same groups, and a reduction in yield potentially due to a reduction in soil P availability. Measurement of baseline soil variables indicated nutrient levels may be adequate, potentially explaining the remaining neutral effects and suggesting the root of the poor productivity may come from the prevalent weed competition rather than fertility issues. However, experimental design flaws and site variations were abundant and likely had strong influences on the outcomes. |
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| Item Description: |
A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information/due to copyright restrictions. |
| Keywords: |
Social-ecological experiment, soil fertility, soil macroinvertebrates, green waste compost, chicken litter, biochar, onion |
| College: |
Faculty of Science and Engineering |