Zakaah on crops cultivated and harvested with machines that need fuel and other expenses
Question

                It is well known that if crops are irrigated by precipitation and rain, one-tenth is due (as zakaah), and if they are irrigated by artificial means, half of one-tenth is due. The difference between them is that crops that are irrigated by artificial means involve a great deal of effort and expense, so it is reduced to half of one-tenth; that which is irrigated by rainfall does not involve a great deal of effort and expense, so the rate is one-tenth. But nowadays, even that which is irrigated by precipitation and rainfall involves a great deal of effort and expense, because it is planted by automatic machines which burn a lot of fuel when being used for cultivation, and may also need chemicals which are very expensive; harvesting is also done by automatic machines that burn a lot of fuel for harvesting and also incur a great deal of expenses. Can an analogy be drawn between this and crops that are irrigated by artificial means because of the effort and expense involved, so that only half of one-tenth is to be paid, or can no analogy be drawn, and thus the rate remains at one-tenth?.
Praise be to Allah.
      The Prophet (blessings and peace of Allah be upon him) 
      connected the ruling to irrigation, and did not pay attention after that 
      to how the crop is harvested or what takes place before that such as 
      levelling the ground. This is something else that does not have anything 
      to do with zakaah. The Messenger (blessings and peace of Allah be upon 
      him) connected the ruling to something else. And the prescriptions of the 
      Messenger of Allah (blessings and peace of Allah be upon him) are for all 
      of his ummah, the first and the last of them. They are not laws that were 
      only for the people of his own time; rather they were for the people of 
      his own time and for all those who come after them until the Day of 
      Resurrection. Allah, may He be glorified and exalted, knew what would 
      happen in the future of newly-invented machines and their need for fuel 
      when harvesting, planting and so on. 

    The things mentioned by the questioner having to do with land 
    that is irrigated with rain water do not have any effect on the rate of 
    zakaah; what must be paid is one-tenth, because of the report that the 
    Prophet (blessings and peace of Allah be upon him) said: “On that which is 
    irrigated by rain, springs and the like, one tenth (is due), and on that 
    which is irrigated by artificial means, half of one tenth (is due).” 
    Narrated by al-Bukhaari in al-Saheeh; there are also corroborating 
    reports. This indicates that the Messenger (blessings and peace of Allah be 
    upon him) did not pay attention to anything done after irrigation or 
    planting, or anything done before that. 

    The ruling is based on the method of irrigation: that which 
    is watered by springs, rivers and rains is subject to complete zakaah of 
    one-tenth: one out of every ten, one hundred out of every thousand, and so 
    on. That which is watered by machines or by using camels or cattle to bring 
    the water and so on, or by sprinklers, is subject to zakaah of half of one 
    tenth, because of the effort and expense incurred to irrigate it. And Allah 
    is the source of strength.                             

    Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allah have mercy on him),