in successive crops, the lessee is not obliged to pay the rent for each crop until that crop is secure and no longer needs water.

Ibn al-Mājishūn agreed with Ibn al-Qāsim that rent for Nile-fed land becomes payable immediately once it has been sufficiently watered, whereas rent for rain-fed land and irrigated land whose water supply is not assured does not become payable until the crop has fully developed and no longer needs water. He disagreed, however, concerning irrigated land with an assured water supply, treating it like Nile-fed land: its rent becomes payable immediately once it has been sufficiently watered.

Thus, there is no disagreement that rent for Nile-fed land becomes payable once it has been sufficiently watered, nor that rent for rain-fed land and irrigated land without an assured water supply does not become payable until the crop is secure and no longer needs water. The disagreement concerns irrigated land with an assured supply: Ibn al-Mājishūn treats it like Nile-fed land, while Ibn al-Qāsim treats it like rain-fed land and irrigated land whose supply is not assured.

According to Ibn al-Mājishūn, land falls into four categories regarding the permissibility of entering into a lease and paying rent in advance:

First: Nile-fed land with an assured water supply.
Second: land irrigated by rivers and wells.
Third: land irrigated by springs.
Fourth: rain-fed land.

Nile-fed land with an assured water supply may be leased for many years, with or without advance payment, close to the season when it receives water and is sufficiently irrigated. This is his position in al-Mudawwana.

Land irrigated by rivers and wells may be leased for ten years, but no longer. According to his position, advance payment is permissible, as reported by al-Fadl.

Land irrigated by springs may be leased only for three or four years, and advance payment may be made only one year at a time. He means that payment for the second year may be made shortly before the first year ends, even if the land has not yet been watered. This is his stated position in al-Wādiha.