The first aliyah discusses the Sabbatical year (also called Shmittah year) and the Yovel (Jubilee) year. For the Sabbatical year, we work our land (in Israel) for six years, but the seventh year is a Sabbath for the land. We don't sow the land, harvest it, or prune it. There are many laws governing what can be done and what cannot and what to do with the fruit that grows by itself and how to be a consumer of produce in such a year. Even outside of the land of Israel we need to be careful about produce and canned goods produced in the land of Israel during a Shmittah year.
After seven sets of seven years we proclaim a Jubilee year with a blast of the shofar on Yom Kippur. In such a year all slaves are freed, and all land reverts to its former owner.
