Bava Metzia 106: Crop Failures and Their Many Consequences
Natural calamities... and how years with no rain (and therefore no produce) were characterized as "Elijah's years." Plus, calculating produce per the years of Shemitah (and Yovel) - and how that connects to redeeming one's conscrated ancestral lands. Plus, mishnah! Cultivating wheat when the crop fails is a challenge to pay back....