Praise be to Allah.
If the land belongs to you, and you fear that you may fall into zina, then getting married is obligatory in your case, and if you cannot afford to get married except by selling this land, then you should sell it, because in that case getting married takes precedence over spending on your parents.
To explain further:
Marriage is obligatory for the one who is able to get married and fears that he may commit zina otherwise.
What is meant by being able to get married is being able to afford the costs of marriage, and what he will spend on his wife.
If he is unable to do that, then he should be patient and fast a great deal, as Allah, may He be exalted, says (interpretation of the meaning): “But let them who find not [the means for] marriage abstain [from sexual relations] until Allah enriches them from His bounty” [an-Noor 24:33]. And the Prophet (blessings and peace of Allah be upon him) said: “O young men, whoever among you can afford it, let him get married. And whoever cannot afford it, let him fast, for it will be a shield for him.” Narrated by al-Bukhaari (5065) and Muslim (1400).
See also the answer to question no. 5511.
The individual is obliged to spend on his parents, if they are poor and he is rich. If he is also poor, then he is not obliged to spend on them.
See the answer to question no. 111892.
If we assume that it is obligatory for a person to spend on his parents, if that conflicts with him getting married in a case where marriage is obligatory for him, then he should give precedence to getting married, because getting married is included in spending on himself, which takes precedence over spending on his parents, just as his spending on his wife takes precedence over his spending on his parents.
It says in Kashshaaf al-Qinaa‘ (5/483):
The one who does not have enough to spend on all of those on whom he is obliged to spend should start with spending on himself, because of the hadith “Start with yourself.”
If he has enough surplus wealth to spend on one or more other people, he should start with his wife, because that it comes under the heading of maintenance in return for something, so it takes precedence over help that the husband may give to others. Hence it is obligatory whether one is well-off or otherwise. Then (in order of who is entitled to maintenance from him) comes his slave,on whom it is obligatory for him to spend at times of ease and of hardship. Then comes the next closest to him and the next closest, because of the hadith of Taariq al-Muhaaribi: “Start with those for whose maintenance you are responsible, your mother and your father, and your sister and your brother, then the next closest and the next closest, because spending (on your dependents) comes under the heading up upholding ties of kinship and showing kindness.” And the one who is closer to you is more entitled to that than the one who is further away from you. End quote.
Our advice is to try to do both, get married and spend on your parents, by keeping some of the land, and being economical in spending on marriage, and looking for a wife who is religiously committed and not demanding, who will be content with little.
See the answer to question no. 223075.
If marriage is not obligatory in your case, and the land is sufficient for your maintenance and that of your parents, then it is not permissible to sell it, because in that case it is obligatory for you to spend on them whilst it is not obligatory for you to get married.
If the land belongs to your parents, or one of them, then it can only be disposed of with the permission of its owner.
And Allah knows best.