The pronoun "we" here includes Nehemiah and the Israelites except for the priests and the Levites, and also does not include the reader of this book (See: [[rc://en/ta/man/translate/figs-exclusive]])
The words "first of" are understood from the begininng of the sentnces. They can be repeated. Alternate translation: "the first of the new wine and of the oil" or "the best of the new wine and of the oil" (See: [[rc://en/ta/man/translate/figs-ellipsis]])
Here "our soil" refers to everything that is grown in the ground. Alternate translation: "the tithes of what we grow in the ground" (See: [[rc://en/ta/man/translate/figs-synecdoche]])