WHyGro-in-Me: Waste-based Hybrid Growing Media for PACE Horticulture using biobased polyurethane binders and biowaste filler

点击翻译按钮获取中文摘要

With the explosive growth in protected cultivation, there has been an increased demand for growing media. This trend is expected to continue in the future, with growing media production predicted to grow by 420% by 2050. Despite the expected growth in conventional media production, there is still predicted to be a shortfall in the market, with a gap of 65 million cubic metres per year to be taken up by "new" growing media [1]. Our team have been focused on the use of polyurethane foams (PUF) as a growing media where we have shown plant growth can be modelled based on foam properties and PUF substrates have matched rockwool in terms of yield [2,3,4]. While virgin PUF shows promise as a hydroponic growing medium, it is difficult to reuse after a growing season due to disease concerns, requiring costly and time-consuming steam cleaning between uses (similar to other substrates) [5].Conventional mixes, on the other hand, often contain a large peat-based component and as the growing media industry looks to "de-peat", alternatives will need to be found. Many components have been suggested and used to some success, including compost, coco coir, wood chips, wood fibre, biochar, and rice hulls. These components, often biowaste products, bring environmental advantages over finite resources such as peat but suffer from variability in terms of physical and chemical properties due to their organic nature and varying sources [6]. This variability leads to variability in growth, a professional grower's nightmare. This is a global challenge that will require a globally viable, science led solution.This project looks to address the challenge of reducing environmental impacts of PACE production, whilst sustainably increasing yields, by synthesising optimised homogeneous growing media using biowaste based fillers from parallel industries to food production (sawdust, wood fibres, spent grain, sheep wool, cotton fabric, etc.) homogenised and bound together using novel biobased and biodegradable polyurethane prepolymers (bPUP) with tunable embedded fertiliser (Figure 1).Our objectives are:Synthesis and characterisation of novel biobased PUP (Our industrial partner, Vita Cellular Foams, will supply bPUP precursors and PUP for testing).Use of bPUP to bond biowaste fillers and generate homogeneous hybrid biobased-biowaste growing media. Use of a design of experiments (DoE) and modelling based approach to optimise these media to increase crop yield by developing crop and system specific "growing media recipes" with optimised embedded nutrient profiles.Material characterisation and initial crop growth trials completed at the University of Sheffield, while our industrial partner, Intelligent Growth Solutions (IGS), will conduct industrial trials using their state-of-the-art vertical farm technology.Exploration of end-of-life pathways using targeted biodegradation, composting and mechanical recycling of growing media by incorporating specific sites for biodegradation.This project has the potential to generate significant scientific advancement through the synthesis and characterisation of novel bPUPs, as well the development of crop and system specific "media recipes" for PACE horticulture. There is also likely to be economic development by commercialisation opportunities arising from this research. In addition, the project can help establish a UK-based area of expertise in growing media development and characterisation, addressing the current lack of representation in this field.