The importance of soil-borne arthropod interactions for plant health.
Research Outputs:

1. Soil nitrogen additives did not greatly influence soil arthropod diversity. However, differences were found in community composition and trophic structure.
2. Stubble burning, a common practice used by many crop farmers, dramatically reduces soil faunal diversity. Quantitative and qualitative recovery to higher levels than pre-burn is recorded after three weeks.
3. Allelopathy probably does not affect soil arthropods as dramatically as soil moisture and compaction does.
4. The ‘home field advantage’ principle is probably a meaningful factor in allelopathic alfalfa litter decomposition.
5. Litter bag soil arthropod sampling is the most reliable technique to use.

RESEARCH

MSc student Ruan du Preez: Impact of soil enrichment practices on soil arthropod species assemblages in cultivated amaranth fields at selected localities (North West Province, South Africa). All field work completed and student writing up. Planned submission in June 2014.

MSc student Hannelene Badenhorst: Mesofaunal assemblages in soils of selected crops under diverse cultivation practices in central South Africa, with emphasis on Collembola. Intensive soil sampling field-work conducted across the Free State on soils of different crops at localities with diverse environmental parameters. This field work is nearing completion and presently the student is following up the ecological trade-off scenario encountered for invasive Collembola species. Overall the student is progressing well.

MSc student Jehane Smith: The influence of genetically manipulated and allelopathic crops on species composition of meso-arthropods in cultivated soils (Free State Province, South Africa). Soil sampling field work has primarily been done around Bloemfontein on soils of crops with variable levels of allelopathic intensity. With the exception of an ongoing ‘home field advantage’ trial using alfalfa litter bags, the overall field work for the project is nearly completed. Overall the student is progressing well.

BSc Hons student Mpho Makhalima: Comparison of pitfall traps, soil sample extraction and litterbags for determining soil arthropod species assemblages. Student completed project and presented results at Postgraduate Seminar Day of Department. Outcome is that litterbags are a significantly more successful technique for determining soil arthropod diversity, demonstrating that the other techniques are therefore less reliable. Student is not continuing her studies.

Manuscript: The unknown underworld: Understanding soil health in South Africa. Submitted to South African Journal of Science.

PRESENTATIONS AT CONGRESSES & WORKSHOPS

1. Badenhorst, H. & Louw, S. vdM. Influences of different agricultural practices on soil mesofaunal assemblages in the central Free State, South Africa. Proceedings of the XVIII Congress of the Entomological Society of Southern Africa, p. 8. North West University, Potchefstroom. July 2013.
2. Du Preez, R. & Louw, S. vdM. Impact of soil nitrogen additives on soil mesofaunal community dynamics in cultivated amaranth field. Proceedings of the XVIII Congress of the Entomological Society of Southern Africa, p. 40. North West University, Potchefstroom. July 2013.
3. Smith, J. & Louw, S. vdM. Soil mesofauna response to Bt maize cultivation in the central Free State, South Africa. Proceedings of the XVIII Congress of the Entomological Society of Southern Africa, p. 124. North West University, Potchefstroom. July 2013.
4. Louw, S. vdM. Belowground communication in soil organisms – Challenges in understanding volatile mediated interactions in the soil. Proceedings of the XVIII Congress of the Entomological Society of Southern Africa, p. 82. North West University, Potchefstroom. July 2013.
5. Louw, S. vdM. Ants in arid regions: Role players in above ground – below ground ecosystem function. 28th Arid Zone Ecology Forum: Emerging threats in the arid zone – building knowledge and developing solutions. Part II: Implications for management, p. 11. McGregor Museum, Kimberley. September 2013.
6. Badenhorst, H. & Louw, S. vdM. Influences of different agricultural practices on soil mesofauna assemblages in the semi-arid western Free State, South Africa. 28th Arid Zone Ecology Forum: Emerging threats in the arid zone – building knowledge and developing solutions. Part II: Implications for management, p. 11-12. McGregor Museum, Kimberley. September 2013.
7. Louw, S. vdM. Change management in cropping system soils: What are the strategies? SA Sugar Industry Agronomists Association Annual Symposium: Soil and plant health. South African Sugarcane Research Institute, Mt Edgecombe. October 2013.