It is narrated from Hazrat Aisha that the Prophet (peace be upon him) said: Whoever cultivates a land that does not belong to anyone, then he is entitled to it.
Hadith Referenceمسند احمد / مسند النساء / 24883
Hadith Gradingحکم دارالسلام:حديث صحيح، ابن لهيعة توبع، خ: 2335