All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
It is confirmed in the Book of Allah as well as the Prophetic Tradition that crops and fruits are liable for Zakah. Allah, The Almighty, Says: "but render the dues that are proper on the day that the harvest is gathered" {A l-An`am/141}.
In addition, Prophet Mohammad (PBUH) said: "A tenth is payable on what is watered by rivers, or rains, and a twentieth on what is watered by camels"{Muslim}.
Shafi`i scholars are of the view that Zakah is due only on crops and fruits consumed for sustenance, not for treatment or luxury. Therefore, Zakah of fruits is due only on grapes and dates; whereas, Zakah of crops is due only on wheat, barley, rice, lentils, corn, chick-pea and beans. However, it isn`t due on sesamum, figs, walnut, almonds and the like.
Al-Imam Ash-Shirbini stated: "Zakah is due on what is consumed for sustenance. From fruits: dates and grapes. From crops: wheat, barley, rice, and lentils." {Moghni al-Mohtajj, vol.2/pp.81}.
As regards the Nissab of crops, it was indicated in the following Hadith: "No Sadaqa (zakat) is due on less than five Wasqs" {Bukhari and Muslim}. In modern measurements, five Wasqs equal (611) kgs. as stated in the book [Al-Maqadeer Ashar`iah" by Sheikh Al-Kurdi pp.201] and the book [Irshad Al-Salikeen] by late Dr. Noah al-Qhodat (May Allah Have mercy on his soul). This Nissab (611) kg. applies to all crops liable for Zakah. Moreover, one-tenth the production should be given for Zakah on crops and fruits watered with rain, and one-twentieth for those watered using equipment.
The majority of the Muslim jurists are of the view that paying Zakah of crops from the product itself is an obligation, and it doesn`t avail to pay it in cash. However, Hanafi`i jurists considered paying it in cash permissible. And Allah Knows Best.