Monfreda, Ramankutty, and Foley (2008) introduce the global dataset of which area harvests which of 175 crops by how much, at the resolution level of 5 min by 5 min latitude-longitude grids. See section 3 in the paper for how the data is constructed.
The dataset is downloadable at EarthStat (click "Harvested Area and Yields of 175 crops).
This dataset is an updated version of the 18 crop data, introduced by Leff, Ramankutty, and Foley (2004).
The dataset is used by Johnston et al. (2009) and Harari and La Ferrara (2013).