Full translation of the letter:
The seventh year shall be a sabbath of solemn rest for the land, a sabbath unto the Lord” (Leviticus 25:4)
The commandment of Shmittah applies to the land, and the entire land belongs to all of Israel.
Every Jew, wherever he is, has a share in the Land of Israel and must do everything in his power to make sure the land rests from doing forbidden things and does only what is permitted in the year of the Shmittah (see “HaEmek Davar”, Natziv from Volozhin, Leviticus 25:4).
Therefore, it is appropriate that every Jew in the world partner with a farmer in Israel to observe the mitzvah of Shmittah along with the other agricultural Mitzvot that apply in Israel, and by doing this, he himself keeps all the mitzvot, for the land belongs to us all.
Therefore, the initiative to share the agricultural mitzvot including Shmittah with all Jews around the world, by partnering with Israeli farmers who keep the Shmittah - through planting fruit trees on the "Zo Artzeinu" website - is to be welcomed and blessed.