According to rabbinic interpretation, Deuteronomy 14: 22-27 refers to a second tithe, a tithe that is separated after the first tithe has already been separated. These verses read:
Deuteronomy 14 22 You shall set aside every year a tenth part of all the yield of your sowing that is brought from the field. 23 You shall consume the tithes of your new grain and wine and oil, and the firstlings of your herds and flocks, in the presence of the LORD your God, in the place where He will choose to establish His name, so that you may learn to revere the LORD your God forever. 24 Should the distance be too great for you, should you be unable to transport them, because the place where the LORD your God has chosen to establish His name is far from you and because the LORD your God has blessed you, 25 you may convert them into money. Wrap up the money and take it with you to the place that the LORD your God has chosen, 26 and spend the money on anything you want -- cattle, sheep, wine, or other intoxicant, or anything you may desire. And you shall feast there, in the presence of the LORD your God, and rejoice with your household. 27 But do not neglect the Levite in your community, for he has no hereditary portion as you have.
While the first tithe goes to the Levite, the second tithe stays in the possession of its owners. The owners must take this tithe to Jerusalem and eat it there. If this is a hardship because they don’t live close to Jerusalem and it would be cumbersome to carry the actual produce to Jerusalem, then they can redeem the second tithe for money, adding a fifth to the value of the produce, and bring all of the money to Jerusalem. There they can use the money to buy food products, either sacrifices or other foods. According to Leviticus 27:30-31, when they redeem the produce for money, they must add an extra fifth to the value of the produce.
Leviticus 27 30 All tithes from the land, whether seed from the ground or fruit from the tree, are the LORD's; they are holy to the LORD. 31 If anyone wishes to redeem any of his tithes, he must add one-fifth to them.
This is the procedure in the first, second, fourth and fifth years of a seven-year sabbatical cycle. The rabbis interpreted Deuteronomy 14:28-29 and Deuteronomy 26:12-15 to refer to the poor tithe, which is separated in the third and sixth years of the cycle.
Deuteronomy 14 28 Every third year you shall bring out the full tithe of your yield of that year, but leave it within your settlements. 29 Then the Levite, who has no hereditary portion as you have, and the stranger, the fatherless, and the widow in your settlements shall come and eat their fill, so that the LORD your God may bless you in all the enterprises you undertake.
Deuteronomy 26 12 When you have set aside in full the tenth part of your yield -- in the third year, the year of the tithe -- and have given it to the Levite, the stranger, the fatherless, and the widow, that they may eat their fill in your settlements, 13 you shall declare before the LORD your God: "I have cleared out the consecrated portion from the house; and I have given it to the Levite, the stranger, the fatherless, and the widow, just as You commanded me; I have neither transgressed nor forgotten any of Your commandments: 14 I have not eaten of it while in mourning, I have not cleared out any of it while I was unclean, and I have not deposited any of it with the dead. I have obeyed the LORD my God; I have done just as You commanded me. 15 Look down from Your holy abode, from heaven, and bless Your people Israel and the soil You have given us, a land flowing with milk and honey, as You swore to our fathers."
In these years the poor tithe, called maaser ani, replaces the maaser sheni, the second tithe. The first tithe is given during all years of the cycle, except for the seventh year.
Maaser Sheni also discusses the laws governing plants or vineyards in their fourth year. This topic is addressed in Leviticus 19:23-25.
Leviticus 19 23 When you enter the land and plant any tree for food, you shall regard its fruit as forbidden. Three years it shall be forbidden for you, not to be eaten. 24 In the fourth year all its fruit shall be set aside for jubilation before the LORD; 25 and only in the fifth year may you use its fruit -- that its yield to you may be increased: I the LORD am your God.
The reason that this topic is dealt with in Tractate Maaser Sheni is that according to halakhah, like maaser sheni, the produce that grows in the fourth year is also brought to Jerusalem, or redeemed and the proceeds are brought to Jerusalem.