Shmitta is a year when agricultural activity is restricted to its absolute minimum. Plowing and planting are forbidden and produce that grows in the land of Israel must be left there for anyone to take. Shmitta is mentioned in the Torah several times. For instance near the end of the book of VaYikra (chapter 25 verse 23) the Torah wrote: "And the land shall not be sold in perpetuity for the land is Mine; for you are strangers and settlers with Me."