“Designer” Wheat Straw for Mushroom Production
Wheat straw used to prepare mushroom compost is highly variable, presenting composters with a number of problems in maintaining compost consistency.
Scientists from AFBI and Warwick HRI studied twelve cultivars from four geographical sites across Northern Ireland and Great Britain
To better understand these differences, a HortLINK project has identified key properties of the straw and how composting can best be adapted to take account of changes in these properties.
With unique access to winter wheat trials, a multidisciplinary team of scientists from AFBI and Warwick HRI studied 12 cultivars from four geographical sites across Northern Ireland and Great Britain. Crop husbandry protocols including fungicide and plant growth regulator (PGR) use (or not) and differing rates of nitrogen fertiliser were investigated. Subsequently, selected straw samples were composted and cropping tests carried out under standard cultivation procedures.
In brief, over 40 parameters were quantified using novel analytical techniques including Thermogravimetry (TG), Vis-Near Infra-Red Spectroscopy (vis-NIR), Instron tensile strength (mechanical properties) and enzymatic bioassays (cellulase, hemicellulase). Results show that growing site and nitrogen fertiliser application had greater effects on the chemical analysis of wheat straw and its subsequent mushroom cropping performance than cultivar or applications of fungicide or growth regulator. High values for dry matter digestibility and/or hemicellulose and cellulose content in the straw produced higher yielding mushroom compost with differences between the ‘best’ and ‘worst’ straw sources of about 50 kg mushrooms per tonne compost (20% yield difference). In the light of these results, trials are now assessing the effects of cultural factors on the relative yields of straw and grain to determine if it is more economic to produce an optimum yield and type of straw that is suitable for mushroom composting, even at the expense of some loss in grain yield.
Selected straw samples were composted and cropping tests carried are out under standard cultivation procedures
Mairead Kilpatrick, AFBI, Loughgall