Zambia is taking up some of the slack, doubling its tobacco production this year. By 2008, analysts predict, it will produce 82 million pounds of flue-cured tobacco a year. That is twice the yield of that in the mid-1970's, before farmland was nationalized, but still far less than Zimbabwe and Malawi each produce now. (source) What does "take up the slack" mean in this example? According to a dictionary, it means "to do the work which someone else has stopped doing, but which still needs to be done." But I don't think it exactly fits to the example above.