Either it is assessed by proportional sharing (muqāsama) or by measurement (misāḥa). If it is muqāsama, those jurists who permitted levying kharaj on a proportional basis regarded it as a determinate entitlement that may validly be assigned as an iqtāʿ. Those who prohibited levying kharaj on a proportional basis regarded it as indeterminate and therefore not validly assignable as an iqtāʿ.
If the kharaj is assessed by measurement, it is of two types. The first is that it does not vary according to the crops planted; this is determinate and may validly be assigned as an iqtāʿ. The second is that it varies according to the crops planted. In this case, the stipend assigned to the recipient must be considered. If it corresponds to the higher of the two kharaj amounts, the assignment is valid, because any amount collected would only result in a shortfall for him. But if it corresponds to the lower of the two kharaj amounts, the assignment is invalid, because it would contain an increase to which he is not entitled.
Once the assignment has been deemed valid in this category, the recipient’s condition during the term of the assignment must be considered, for it can only fall into one of three situations. The first is that he remains alive and in good health until the term expires. In that case, he remains entitled to the iqtāʿ until the end of the term.
The second is that he dies before the term expires. The iqtāʿ is then terminated for the period remaining after his death and returns to the Bayt al-Māl. If he has descendants, they are included among those receiving grants for soldiers’ dependents, not among the stipends of the soldiers themselves; what they receive is a family allowance, not an iqtāʿ.
The third is that he becomes afflicted with a chronic disability, leaving him incapacitated for the rest of his life. As for whether his iqtāʿ remains in effect after his disability, there are two possibilities. The first is that it remains his until the end of the term, if it is held that his stipend does not lapse on account of disability. The second is that it is reclaimed from him, if it is held that his stipend does lapse on account of disability. This, then, is the ruling for the first category, when the iqtāʿ is assigned for a specified term.
The second of its categories is that it be assigned to him for his lifetime and then to his heirs and descendants after his death. This iqtāʿ is invalid, because by means of it he has transferred what belongs to the rights of the Bayt al-Māl into inheritable property. Once it is invalidated, whatever he collected from it is treated as having been authorized under a defective contract. The kharaj payers are therefore discharged of their obligation by paying it, and it is counted as part of his stipend. If it exceeds his stipend, he must return the excess; if it falls short, he may claim the remainder. If the ruler publicizes the invalidity of the iqtāʿ so that the recipient refrains from accepting it and the kharaj payers refrain from paying it, then, if they pay it after that has been made known, they are not discharged of the obligation.
The third category is that it be assigned to him for his lifetime only. There are two possibilities regarding the validity of this assignment. The first is that it is valid if it is held that the onset of his disability does not entail the loss of his stipend. The second is that it is invalid if it is held that the onset of his disability necessarily causes his stipend to lapse.