Since over 99% of the world's population had disappeared, the Amish were free to expand their families and their farms as far as they liked, and had sought out new territories to colonize.
Yoney Hochstetler, a Pennsylvania Amish bishop with an attitude who had wryly coined the term "After the Rapture" and devised a new calendar, led a group of Amish settlers to the site of the former New York City, where they discovered to their surprise that some of the best farming land on earth was to be found in the Bronx.
Hochstetler returned to Lancaster County, which was in the throes of a crisis engendered by the overproduction of dung by the expanded farm animal and Amish population explosions. He eventually convinced almost all of the North American Amish to join the new colony in New York. While most members of the community welcomed the chance to migrate as a breath of fresh air, a few of the more recalcitrant and retentive brethren stayed behind. Vowing that all that good hot dung should not chust go to waste, they promised to join the colony in New York when they had perfected a means to harness its power as more than chust fertilizer.