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Incorporating silicon-based bioproducts into crop protection programmes to improve agricultural sustainability

Primary Supervisor: Dr Joe Roberts, Department of Agriculture and Environment

Secondary supervisor: Dr Tom Pope (HAU) and Dr Martin Hare (HAU)

PhD project title: Incorporating silicon-based bioproducts into crop protection programmes to improve agricultural sustainability

University of Registration: Harper Adams University

Project outline:

Agronomic advances driven by the ‘green revolution’ have facilitated significant crop production increases since the Second World War. Conventional agricultural production systems rely on intensive synthetic inputs to attain maximal yields, particularly with respect to protection against crop pests (i.e., pesticide use) and nutrient provision (i.e., fertiliser use).1 Modern agricultural production systems increasingly demand alternatives to synthetic inputs due to legislative changes, high levels of resistance to active ingredients in target organisms and concern surrounding their impact on environmental and human health.2-4 Finding effective alternatives to synthetic inputs is, therefore, vital to meet sustainability demands while also ensuring food security and profitable harvests. Biopesticides and biostimulants are products based on natural substances, or their derivatives, that offer an alternative to synthetic inputs and there is an emerging market for ‘bioproducts’ containing silicon.

Silicon (Si) is the second most abundant element in the earth’s crust and ubiquitous in both soil and terrestrial plants.5 During the early 1900s Si was proposed to be an essential plant element, but this is now debated due to a lack of definitive evidence supporting its role in plant metabolism.5 Most terrestrial plants accumulate Si in their tissues as monomeric or monosilicic acid (H4SiO4) absorbed through the roots, though accumulation varies between plant species and cultivars.5 Despite being non-essential for plant growth, Si is widely considered ‘agronomically essential’ as it facilitates resistance against key abiotic (e.g., salinity, drought) and biotic stresses (e.g., insect herbivores and pathogens).6-7 While the agronomic benefits of Si have been demonstrated at laboratory and field scale, use of silicon-based bioproducts in UK agricultural production systems have yet to be optimised and the mechanisms underpinning their biological effects, particularly with respect to mitigating biotic stress, are not fully understood.

This project will test the efficacy of existing and novel silicon-based bioproducts to mitigate biotic stresses (insect herbivory and plant pathogens) in a key arable crop (e.g., oilseed rape). An understanding of how these products interact with crops will enable us to optimise their application to provide on-farm benefits.


1Savary et al. (2019) Nature Ecology and Evolution 3: 430-439; 2Sparks and Nauen (2015) Pesticide Biochemistry and Physiology 121: 122-128; 3Fantke et al. (2012) Environment International 49: 9-17; 4Ollerton et al. (2014) Science 346: 1360-1362; 5Tubuna et al. (2016) Soil Science 181: 393-411; 6Coskun et al. (2016) Frontiers in Plant Science 7: 1-7; 7Wang et al. (2017) Frontiers in Plant Science 8: 1-14.

BBSRC Strategic Research Priority: Sustainable Agriculture and Food:Plant and Crop Science

    Techniques that will be undertaken during the project:

    • Soil physicochemical analysis
    • Air entrainments to collect volatile organic compounds from organic material
    • Gas chromatography-mass spectrometry to identify volatile organic compounds
    • Insect assays to determine behavioural responses and mortality rates
    • Polymerase chain reaction (PCR) for gene expression studies

    Contact: Dr Joe Roberts, Harper Adams University