Small is a relative term, even many of the vineyards in California wine country are many hundreds (and sometimes thousands) of acres in scale. A device only capable of a payload for 10-20 acres of application is hardly efficient when most farms are to this larger scale. Here in the PNW we grow nearly every major US crop, and Washington in particular has become a front runner in American viticulture with many thousands of acres of vineyards. So the situation is not so different, in fact it is quite similar. The other issue you have when selling to small farmers is that they do not have the budget to add such a specialized machine. They already own the ground rigs necessary to maintain their crops (yes, even row crops, getting through a vineyard is a lot easier than you might think) and when equipment payments make up the majority of expenses (especially on small farms) it would make a difficult sell. Larger farms have more capital budget available and could definitely afford and benefit from UAV technology, but their usefulness will largely be in its imaging and mapping capabilities. While I am sure applications with it will be handy at times it will in large part be its secondary use.

I work for an Ag company in the Pacific Northwest and I can tell you that while there is a use for UAV technology in agriculture, it is not an end all replacement for spraying and other applications. It lacks the payload to be efficient with all farms, many are too large to be sprayed in total with such a small device. Also the article seems to vilify the tractorand current methods to a certain degree, when in fact precision agriculture has helped implement gps, autosteer, and autoboom technology (among many other things) into modern agriculture already and has drastically increased the precision with which we apply fertilizers and crop protectants. I also don't understand why we are wasting money on research for this particular device when it already has decades of use and data available, especially when looking at spray patterns from helicopters since those are already used for this application and have been for over sixty years. UAVs will be a great asset for mapping, collecting field data, and making applications to small crops, but it will just be another small tool, and is not the end all solution for precision ag.