The Shaykh (Al-Mufid), may Allah سبحانه وتعالى have mercy on him, said: “Likewise, there is no zakat on produce until its amount reaches the limit upon which zakat becomes obligatory, after estimation (khars) and harvesting (jidhadh), and after its expenses and the tax of the ruler (kharaj al-sultan) have been deducted.”
Commentary #2