The First Topic: Definition of the Sale of Muhaqala Linguistically and its Islamic (Shari'a) meaning:
· Linguistic Definition of "Muhaqala": Haql (plural: huqool) refers to barren land without trees. It is also said that it refers to crops whose leaves have spread, and from this, the term muhaqala is derived [291] -"Tahdhib al-Lughah" by Al-Azhari (4/31); "al-Zahir" by Al-Azhari (p. 137);"al-Misbah al-Munir" (1/144) .
· Islamic (Shari'a) Definition of Muhaqala: It refers to selling the grain on crops for a specific measure of the same type of grain [292] - See:" Ikmal al-Mu'lim bi-Fawa'id Muslim by Al-Qadi Iyad (5/189), "Al-Mughni "by Ibn Qudamah (4/156), al-Majmu' by al-Nawawi (9/309). See: al-Kafi by Ibn Abd al-Barr (2/656) .
The Second Topic: The Ruling on the Sale of "Muhaqala"
The sale of muhaqala is prohibited and invalid [293] -Ibn 'Uthaymin said regarding the meaning and forms of the sale of muhaqalah: "A person comes and sells his field to another in exchange for their field. For example, I have a farm, and you have a farm, and I sell my farm to you in exchange for yours, and both of them are wheat fields. This is not permissible. Why? Because selling wheat for wheat requires equality in measure, and equality here — when the wheat is still on its stalks — is impossible, making this transaction impermissible due to the involvement of Riba (usury). Another example of muhaqalah: A person sells unharvested crops with the condition that they will be harvested in a month for dry, harvested wheat. This is also impermissible. Why? Because it is impossible to know the exact measure. If we assume that the harvested wheat is known, the unharvested crops are unknown. Thus, it is a sale of unknown wheat for known wheat, which is not permissible." See: Fath Dhi al-Jalal wa al-Ikram by Ibn 'Uthaymin (3/572). , and this is agreed upon by the four schools of Islamic jurisprudence: Hanafi [294] -See: "Tabyin al-Haqa'iq" by al-Zayla'i (4/47); "al-Binayah" by al-'Ayni (8/153). , Maliki [295] -See: "al-Kafi" by Ibn Abd al-Barr (2/656);  "al-Dhakhira" by al-Qarafi (5/392). , Shafi'i [296] -See: "al-Majmu'" by al-Nawawi (9/309); "Tuhfat al-Muhtaj "by Ibn Hajar al-Haytami (4/471) , and Hanbali [297] -See: "al-Furu' " by Ibn Muflih (6/305); "Kashaf al-Qina' "by al-Buhuti (3/258) . This consensus has been reported [298] -Al-Nawawi said: "The scholars have agreed on its invalidity."  See: "al-Majmu'" (9/309). .

The Evidences:
Firstly: From the Sunnah
On the authority of Jabir ibn Abdullah (رضي الله عنهما), he said: "The Messenger of Allah صلى الله عليه وسلم forbade muhaqala, muzabana, mu'awama, and mukhabara—one of them said: selling for years is mu'awama—and also forbade thunaya, and permitted ariyya sales. [299] - Narrated by Muslim (1537). "
Reasoning:
The Prophet صلى الله عليه وسلم prohibited "muhaqala", and prohibition implies impermissibility and invalidity [300] - See: "Kashaf al-Qina' "by al-Buhuti (3/258). .
Secondly:
It involves the sale of wheat and straw for wheat [301] -"Because he sells wheat while it is still on its stalks, along with the chaff — which is the residue of the crop — for pure wheat." , which is considered Riba due to the absence of equivalence or the ignorance of its equality [302] - See:" al-Majmu'" by al-Nawawi (9/309); "Kashaf al-Qina' "by al-Buhuti (3/258). .
Thirdly:
It involves selling a measured commodity for another of the same type, and it is not permissible through estimation, due to the potential of Riba being present in reality, thus making it prohibited [303] - See:" al-Binayah" by al-'Ayni (8/153). .