He adds his brother’s produce to his own so that the government can market it without (the government) knowing
Question

                I have some land that was given to me by the government to cultivate it, and the government takes care of marketing the produce. At present the government takes care of marketing the date harvest. I have a brother who asked me to take some of the yield of his own land in another area, so that I could add the produce from his land to my own harvest, so that the government will market it. Of course this is without the knowledge of the government department that takes care of marketing. What is your opinion on this?.
Praise be to Allah.
      It seems from your question that the state is only 
      marketing the dates grown by the people who are taking part in these 
      projects so as to encourage and help them, and it is not doing that for 
      other people. Hence it is not permissible for you to take some of your 
      brother’s produce and give it to the government unless you tell them about 
      that, because this comes under the heading of deceit, lying and consuming 
      people's wealth unlawfully, and all of that is haraam. 

    What you should do is cooperate with the government in the 
    beneficial things that it is doing, so that these efforts will be successful 
    and will bear fruit, and this will prompt the government to do more 
    beneficial things. 

    As for tricking the government by doing such things, this is lying and deceit, and it may ultimately lead to the cancellation of these projects, so those who do these tricks will become the cause of hardship for the people. 

    And Allah knows best.