I was at the sea and on the way back it occurred to me two simple axioms. One is that you need the third growth and smoothing of the stack to be in the hands of a Israel in order to be obligated in truma and maasar. That is however according to the opinion that a gentile has the ability to acquire land in Israel in such a way as to take away the obligation of truma. However according to the alternative opinion that a gentile cannot own land in such a way then even if he has acquired that land an the wheat has grown to a third of it final growth in his hands, even so that wheat is obligated in truma. The other axiom is that the land can be owned by one person and what grows on it can be owned by other (as Rav Shach pointed out. E.g., land that is not owned by anyone, and yet someone sowed it, the crop is obligated in truma). So even if the land is in the hands of a Israel but a gentile owns the wheat, it still is not liable unless both the third and the smoothing are when the Israel owns the wheat. Based on these two principles it is possible to understand the argument between the Gra and the Kesef Mishna about the intention of the Rambam in laws of truma where he says if land is owned by a gentile in Israel, and a Israel buys the land back he is liable in truma from the Torah the Keseph Mishna writes there that therefore if that land has not been bought back by a Israel the grain is not obligated in truma. The Gra wrote that this is a mistake as one can see in the next halacha that if one buys grain from a gentile, if the smoothing was done in the hands of a Israel it is obligated in truma. I think the Keseph Mishna means thatif the third growth was in the hand of a gentile, the grain is not obligated in truma from the Torah, but rather derababan.--------------------------------I was at the sea and on the way back it occurred to me two simple axioms. One is that you need the third growth and smoothing of the stack to be in the hands of a יהודי in order to be obligated in תרומה and מעשר. That is however according to the opinion that a gentile has the ability to acquire land in Israel in such a way as to take away the obligation of תרומה. However according to the alternative opinion that a gentile cannot own land in such a way then even if he has acquired that land and the תבואה has grown to a third of it final growth in his hands, even so that תבואה is obligated in תרומה. The other axiom is that the land can be owned by one person and what grows on it can be owned by other (as רב שך pointed out. E.g., land that is not owned by anyone, and yet someone sowed it, the תבואה is obligated in תרומה). So even if the land is in the hands of a יהודי but a gentile owns the תבואה, it still is not liable unless both the third and the smoothing מירוח are when the יהודי owns the תבואה. Based on these two principles it is possible to understand the argument between the גר''א and the כסף משנה about the intention of the רמב''ם in laws of תרומה where he says if land is owned by a gentile in Israel, and a יהודי buys the land back התבואה is חייב in תרומה from the תורה. the כסף משנה writes there that therefore if that land has not been bought back by a יהודי ,the תבואה is not obligated in תרומה. The גר''א wrote that this is a mistake as one can see in the next halacha that if one buys תבואה from a gentile, if the smoothing was done in the hands of a יהודי ,it is obligated in תרומה. I think the כסף משנה means that if the third growth was in the hand of a gentile, the grain is not obligated in תרומה from the Torah, but rather דרבנן.--------------------------------