Is a sharecropping agreement valid if specific proportions are assigned to specific crops, provided the quantity planted of each crop is determined?

Primary text

It is permissible to arrange a Mazar'ah (farming partnership) where the laborer is assigned one-third of the wheat, one-half of the barley, and two-thirds of the broad beans, provided the amount to be planted of each type is specified. This specification can be achieved by determining the seed amount, designating and specifying the area for each crop, or by calculating the area through measurement, such as stating 'you will plant this area with wheat and that area with barley,' or specifying quantities like 'two mudd of wheat and two mudd of barley,' or 'one qafiz of wheat and two qafiz of barley.' This is permissible because each method leads to certainty and knowledge regarding the shares.