Advancing our understanding of soil particulate organic matter dynamics

This study aimed to characterize the diversity and complexity of soil particulate organic matter (POM) across California agricultural fields. By identifying the chemical signature of this small but significant organic matter fraction, researchers can build a deeper understanding of how it contributes to nutrient and carbon cycling in Mediterranean agroecosystems. We utilized Fourier‐transformed infrared spectroscopy to identify relative abundances in POM functional group composition and characterize the POM fraction across annual cropping systems in California. We found that POM from soils that developed under anaerobic conditions had accumulated high‐energy aliphatics and had a higher degree of decomposition and less persistence (indices of decomposition [IoD] of 0.54 and indices of recalcitrance [IoR] of 0.92, respectively). Conversely, POM from soils developed under dry aerobic conditions was less decomposed and had higher recalcitrance (IoD of 0.47 and IoR of 1.04, respectively). This has important implications for biochemical cycling regarding nutrient turnover from POM as we strive to improve our understanding of organic matter cycling in California.