Field experiments using a sand particle counter and an optical particle counter clarified the links between saltation and dust emission under wet and weakly crusted conditions in a fallow field previously cultivated with wheat in Australia. A crust was formed by the impact of raindroplets after small precipitation events. A little soil moisture enhanced the strengths of crust and aggregation even though the soil was dried. Dust concentration was proportional to friction wind velocity, but the proportionality was dependent on ground surface conditions, such as the minimally dispersed particle size distribution of parent soil and the presence or absence of crust.