Is the owner of agricultural land obligated to pay money for the service of the land if he will take a percentage of the harvest, and does he recover his capital upon harvesting?

It is permissible for the landowner to give his land to someone to cultivate it for a known share of its produce, such as half or a quarter. It is also permissible for the land, seeds, and tools to be from the landowner, and the labor from the other party, with the laborer's wage being what was stipulated for him from the produce of the land. However, it is not valid for the landowner to take the cost of cultivation (such as seeds and tools) from the produce and then divide the remainder with the worker, as this constitutes gharar (definition) (excessive uncertainty). It is stated in Kashshaf al-Qina': "If the cultivator stipulates that the landowner takes the equivalent of his seeds and then they divide the remainder, this is invalid, as if he stipulated a known number of qafiz (a measure of volume) for himself. This is an invalid condition that invalidates the muzara'ah (sharecropping agreement), because the land might not produce more than that amount, in which case the owner would exclusively take it, and perhaps it would not even produce that much."