Use of Near-Infrared Spectroscopy to Predict Potential Mushroom ( Agaricus Bisporus ) Yield of Phase II Compost

The yield of fruiting bodies of Agaricus bisporus from compost is variable due to differences in available nutrients and cultural conditions during production. The objective of this study was to evaluate the use of near-infrared (NIR) reflectance spectroscopy for assessing potential compost productivity. Three compost comparative trials, carried out over the past six years under controlled experimental conditions, have generated a large sample set (48 × 3 = 144) with yield data. Visible and NIR reflectance measurements of the calibration samples were made over the range of 400–2498 nm. A partial least-squares (PLS) algorithm was used to generate the predictive models using the information in the spectrum. A model developed with the spectral region 1100–2498 nm could explain 87% of the variation in mushroom yields obtained from the three trials. The accuracy of the NIR yield model has been confirmed in a validation compost comparative trial. A combined calibration equation (r² = 0.93) using the spectral data (1100–2498 nm) from the four trials was developed with a standard error of cross-validation of 18.6 kg/tonne.