PhD Scholarship in Horticultural Crop Production
Effects of organic and conventional crop protection and fertilisation regimes and variety choice on crop health, yield and nutritional quality parameters in field vegetable crop
Organic crop production standards prohibit the use of synthetic chemical pesticides and mineral N, P and KCl fertilisers that are commonly used in conventional vegetable production. Organic producers also often grow older varieties with high sensory quality and avoid the use of hybrid genotypes selected for yield and shelf life.
Recent systematic literature reviews reported that organic crop production protocols result in a significant reduction in crop yields, soil borne and foliar disease severity, pesticide residues and cadmium levels, but higher antioxidant, nitrate/nitrite and zinc concentrations in crops (Giotis et al. 2012; Baranski et al. 2014, Rempelos et al. 2018). However, there is very limited information on the relative contribution of contrasting agronomic factors (e.g. crop protection, fertilisation, variety choice) on the differences in crop health, yield and nutritional quality parameters between organic and conventional field vegetable production systems. The use of long-term, factorial field experiments was recently shown to allow relative effect of (and interactions between) specific agronomic factors (pre-crop, crop protection and fertilisation) on health, yield and nutritional quality parameters in wheat crops to be quantified (Cooper et al. 2013; Baranski et al. 2014).
The SCU/NSW-DPI Centre for Organics Research (COR) and Southern Cross Plant Science have established two unique factorial field experiments in collaboration with TAFE Wollongbar and Bauer Farms/Organic Farm Gate. Experiments are designed to identify/quantify effects of (and interactions between):
- crop protection (with and without the use of pesticides),
- fertiliser type (mineral NPK, household waste compost, composted cattle manure and chicken manure pellets),
- variety/hybrid choice and
- cover crops (with and without) on health, yield, nutritional and sensory quality parameters in nine different field vegetable crops (broccoli, tomato, carrots, ginger, turmeric, celery, French beans, spinach and coriander). Soil chemical, physical and biological, environmental impact and production cost parameters will also be recorded in these experiment to allow both financial and environmental cost/benefit analyses.
- Barański, M., Średnicka-Tober, D., Volakakis, N., Seal, C., Sanderson, R., Stewart, G.B., Benbrook, C., Biavati, B., Markellou, E., Giotis, H., Gromadzka-Ostrowska, J., Rembiałkowska, E., Skwarło-Sonta, K.,, Tahvonen, R., Janovská, D., Niggli, U., Nicot,P. and Leifert, C. (2014) Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analysis. British Journal of Nutrition 112, 794–811.
- Cooper, J., Sanderson, R., Cakmak, I., Ozturk, L., Shotton, P., Carmichael, A., Sadrabadi Haghighi, R., Tetard-Jones, C., Volakakis, N., Eyre, M., and Leifert, C. (2011) Effect of organic and conventional crop rotation, fertilization and crop protection practices on metal contents in wheat (Triticum aestivum). Journal of Agricultural and Food Chemistry 59, 4715–4724.
- Giotis, C., Theodoropoulou, A., Cooper, J., Hodgson, R., Shotton, P., Shiel, R, Eyre, M., Wilcockson, S., Markellou, E., Liopa-Tsakalidis, A., Volakakis, N. & Leifert, C. (2012) Effect of variety choice, resistant rootstocks and chitin soil amendments on soil-borne diseases in soil-based, protected tomato production systems. European Journal of Plant Pathology 134, 605–617.
- Rempelos, L., Almuayrifi, A.M., Baranski, M., Tetard-Jones, C., Eyre, M., Shotton, P., Cakmak, I., Ozturk, L., Cooper, J., Volakakis, N., Schmidt, C., Sufar, E., Wang, J. Wilkinson, A., Rosa, B.A.S., Zhao, B. Rose, T.J., Leifert, C. and Bilsborrow, P. (2018) Effects of agronomic management and climate on leaf phenolic profiles, disease severity and grain yield in organic and conventional wheat production systems Journal of Agricultural and Food Chemistry DOI: 10.1021/acs.jafc.8b02626
The project will focus on quantifying the effects of (and interactions between) contrasting crop protection protocols (with and without applications of synthetic chemical pesticides), fertiliser types (mineral NPK, household waste compost, composted cattle manure and chicken manure pellets) and variety/hybrid choice on crop health, yield, nutritional and sensory quality parameters in two selected vegetable crops . The work will include:
- Targeted critical review of existing relevant peer-reviewed scientific literature
- Systematic literature review and meta-analyses of studies reporting comparative data on pesticide, phytochemical, toxic metal and mineral concentrations in organic and conventional vegetable crops
- Assess weed density, disease and pest severity and crop yield and visual quality parameters in field vegetable crops in two factorial field experiments
- Collect soil and crop tissue samples in field trials for analyses
Carry out relevant phytochemical analyses including calorimetric assays for antioxidant activity and HPLC based analyses of nutritionally relevant antioxidants and phytochemicals at the SCU plant science labs in Lismore.
This studentship would be suitable for a graduate in agricultural, biological, environmental or related sciences. The student will receive training in:
- Soil and crop management in organic and conventional field vegetable production systems
- Critical and systematic review of scientific literature and meta-analysis methodologies
- Experimental design, data management and statistical analyses using R
- Establishment, management and assessment of crops of field experiments
- Extraction and analytical protocols of plant phytochemicals
- Writing research papers for peer-reviewed scientific journals
- Preparing reports and preparing presentations for scientific audiences, farmers/growers and consumers
In addition, this studentship will be managed within the postgraduate training programme in Plant Science Innovation, which provides opportunities to benefit from a broader range of professional training alongside the focused research project.
Links to ongoing work and potential collaboration
The Centre for Organics Research (COR) is a joint research centre between Southern Cross University and NSW Department of Primary Industries which conducts research in partnership with community and industry stakeholders. The Centre for Organics Research provides strong evidence-based scientific and multidisciplinary research focused on clarifying some of the complex issues surrounding organics production and supply chains. This includes research into the comprehensive reach of organic production covering such broad themes as integrated production systems, sustainable resource management, economics and markets, and education and health.
Southern Cross Plant Science is a Research Centre within Southern Cross University (SCU), and carries out research underpinning the selection, cultivation and utilization of plants. SCPS infrastructure includes facilities for plant growth, analytical chemistry, high-throughput DNA sequencing, genotyping, proteomics and bioinformatics. The candidate will also benefit from expertise and experimental resources available within the wider SCU research environment. SCU has achieved the highest rating of exceptional performance, well above world standard in the past two national assessments of research excellence (2012 and 2015) for crop and pasture production and agricultural science.
COR has developed a close working collaboration with TAFE Wollongbar and Bauer Farms/Organic Farm Gate, who support the management of the two factorial field trials used in the PhD research project.
Value of scholarship
Three years at $30,000 per annum.
This project will be based at SCU’s campus in Lismore, NSW, Australia, and will involve the student working in the context of an industry-sponsored collaboration.
Deadline for applications
Friday 29 March 2019.