Salim bin Abdullah narrates from his father (may Allah be pleased with them both) that in the time of Umar (may Allah be pleased with him) people used to mark off land with stones. He said: "Whoever revives land, it is his." Yahya says: It is as if he did not make it his merely by marking it off until he revives it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب إحياء الموات / 11820