Soil organic carbon and nitrogen pools are increased by mixed grass and legume cover crops in vineyard agroecosystems: Detecting short-term management effects using infrared spectroscopy

•Grass and legume cover crops increase total, coarse and fine fraction SOC under-vine.•Mixed cover crops increase plant available N by 75%; 17% greater than legumes alone.•IR/PLSR accurately predicted SOC mg g−1 in bulk soil, coarse and fine fractions.•Changes to SOC pools under cover crops were accurately detected using derived models. The incorporation of cover crops in orchards and vineyards can increase soil organic carbon (OC) and improve nitrogen (N) availability. This study compared how three herbaceous under-vine cover crop assemblages affected OC and N pools in four edaphically distinct vineyard agroecosystems. Using physical fractionation and soil spectral analysis we: 1) compared effects of grass and legume mono- and poly-cultures on total, coarse (≥50 µm) and fine (