Quantifying aerosol impacts on clouds, precipitation and climate however is very uncertain and strongly impacts assessments of future climate. This large predictive uncertainty in part originates from the variability and range of aerosol types that act as the seeds for forming ice crystals. Airborne dust is by far the most important contribute to ice nuclei (IN), and can strongly modulate mixed-phase and ice cloud properties. IN emitted from exposed soils, termed fertile soils, is an important contributor to atmospheric dust, with a trend that will increase in the future. yet least understood type of dust IN. It is thought that the IN activity of fertile soils can be very different from mineral dust, owing to the presence of organic compounds and biological material; very little data however exists on its IN activity and the role of non-mineral components. Here, we propose to (1) Characterize the properties of fertile soil samples from various locations and areas of land use, focusing on the relative importance of organic and biological material attached to the native particles; (2) Characterize the properties of ice residuals and interstitial aerosol particles from the samples characterized in part 1; and, (3) Parameterize the observed IN activity for use in aerosol-cloud interaction modules and carry out a global modeling study that quantifies the potential impact of fertile soils on clouds, the hydrological cycle and climate. Upon completion, this project has the potential to transform our understanding how current and future land use change and the resulting dust emissions from exposed soils can impact clouds, the hydrological cycle and climate. The data required to understand the IN properties of fertile soils and the impact of attached organic material thereon require the detailed probing of aerosol surface properties with state-of-the-art facilities that only EMSL offers.