Probably a "Tomcat" (I think). I think it is a modified Bell 47 for ag work.
In my area, there have been several "attempts" made at using the helicopters but it usually doesn't last over a year or two. We deal with lots of high volume spraying (10 gallon per acre) mostly and most of the helicopters set up for ag work that I have seen are of the Bell 47 or Hiller variety. I don't think they can carry much over a hundred gallons or so tothe load. We alo deal with huge amounts of fertilizer poundage. For fertilizing work we put about 200-300 lbs. per acre so a big hopper capacity is crucial to producing the volume of work that we deal with daily.
Having said that, they certainly have their place and are quite efficient at what they do. They will turn on a dime and they have no ferry time by loading on or beside their truck at the field. And they are cool to watch.