In one of the most agriculturally diverse production regions in the world, California researchers and producers face unique and complex challenges. With this study, we have elucidated several important research questions addressing those challenges, namely, how organic matter content affects nitrogen (N) mineralization across the tapestry of soil types under cultivation using an N-budget approach, the connection between expected yield and maximum N accumulated in aboveground biomass for two important cash crops, the diversity in chemical composition of the particulate organic matter fraction and how it pertains to organic matter and nutrient cycling, and how infrared chemical signatures can potentially be used as a surrogate for time-consuming laboratory analyses. We observed that high organic matter soils (> 30 g C kg-1 soil) mineralized an average of 2.2 kg N ha-1 day-1 over the growing season and that low organic matter soils mineralized 1.1 kg N ha-1 day-1. We found that for grain corn and hybrid sunflowers that crop yield and maximum N accumulated in the aboveground biomass were significantly correlated. We also found that particulate organic matter (POM) originating from high organic matter soils was more decomposed and had lower recalcitrance than the less decomposed and more recalcitrant low organic matter POM, using infrared spectra. We were also able to the estimate potential N mineralization from undisturbed soil cores with 90.1% accuracy in high organic matter soils (n=25) using solely infrared spectra and partial least squares regression. This information will allow those who work in agroecosystems across the state to make informed decisions regarding issues such as fertilizer management, further studies on organic matter influences on biochemical cycling, and the most efficient approach for estimating soil characteristics.