Quantitative NIR spectroscopy determination of coco-peat substrate moisture content: Effect of particle size and non-uniformity

•A NIR detection method considering the effect of particle size and non-uniformity is proposed.•Smaller particle size resulted in higher precision spectral prediction performance.•Higher uniformity resulted in better spectral prediction model for NIR spectroscopy detection.•MSC and SNV have good effects on improving the performance of small particle size sample models.•The performance of uniform sample model can be improved better by MSC and SNV.