Johann Friedrich Mayer (agriculturist)

Johann Friedrich Mayer, born in 1719 and died in 1798, was a German Reformed pastor who became one of the most influential agricultural reformers of the late eighteenth century. He championed crushed gypsum as a fertilizer, publishing his findings in 1768 and earning the nickname Apostle of Gypsum, and his 1773 textbook introduced crop rotation systems that broke from the medieval three-field system along with farmhouse designs integrating living quarters above barns for heat retention that became iconic in the Hohenlohe region. He also advocated new crops such as potatoes, clover cultivation on fallow land to expand livestock fodder and manure supply, and social reforms including free property rights for peasants and the abolition of forced labor, with his influence and gypsum methods spreading across Europe and North America.