This pictures are of a friend as he is spraying Cannabis (Herbicide not Fertilizer!) in the mountains of Mexico, they are taken at 7,000 FT.
They work in pairs, a 206 above with armed guys watching the sprayer below as he does his thing, very common work around here, unfortunately there is soo much demand for drugs north of the border that many poor farmers have began turning their crops into things such as Opium and Cannabis.
As you can see these people grow the stuff as hidden away as possible to make it harder for the helicopters to spray it, many fields have steel wires strung above them to keep helicopters away.
