All perfect praise be to Allah, peace and blessings be upon prophet Mohammad and upon his family and companions.
The agreement between the workers and the owners of the vehicles regarding carrying the former into the desert in return for a fixed percentage of the fruit product is called in Islamic jurisprudence” Ijjarat Zimmah.”The General Iftaa` Department had previously chosen to answer this Fatwa with two important opinions: First: It is permissible in “Ijjarat Al-Zimmah" that the rent is deferred, or paid by installments and not to be prompt cash.
This is according to the Hanafites and Hanbalites, but not the Shafites. Refer to Fatwa No.(270). Second: It is permissible that the rent is an indefinite percentage, and not a specific amount. This is according to the opinion of the Hanbalites , and not the Shafites. Refer to Fatwa No.(853).
Based on the above, we see no harm in the agreement concluded between the seasonal workers and the owners of the vehicles regarding carrying the former in return for a rent with a known percentage from the fruit product. And Allah Knows Best.