VirginiaHistorian's assertions about yeoman v. planter production are misleading since they look at production per acre, not percentage of overall economy, which was dominated by the planters. Look at Table 2 on page 74 of this paper. (It's inconveniently sideways.) 
 ::*To what method of fertilization do you refer? Crop rotation? 
 ::*McCormick's reaper was not for sale until after Jefferson's death.