Everybody needs and uses the same 4 basics. The difference is the last one, water. In some area's of the Nation,, mother nature takes care of the watering. Granted she gets sloppy with the timing and amounts,, but it does simply fall out of the sky without any cost.

Where possible, and the infrastructure is available water is necessary and a costly investment,changes the input costs, and in some area's is absolutely vital to be able to produce a crop. 

In my area as an example,, everybody would simply not farm without an infrastructure to provide water. Living in the shadow of the Cascade range we get something like 9-16 inches of moisture most of which is snow which falls in the higher elevations of the Cascade range. During the crop growing year coyotes are packing canteens, rain is almost non-existant. Per acre which ever way water is applied to fields (rill, gated pipe, pipelines, sprinklers and pumps, open ditches, plus labor, etc)  becomes a "set input cost" not a discressionary input, such as putting on a little less crop nutrients, etc.  Water itself, its application, and equipment of all types is a major on going yearly cost. Which means  costs are exactly the same whether a person grows 40 bu/wheat or 130 bu/ wheat. With that *hard cost* involved, there is only acceptable 1 target yeild- -  MAXIMUM.    (there is a good reason much of the west has sagebrush)

Irrigation in many areas of the west irrigationg and it's associated costs are absolutely necessary to grow a crop, irrigation is not a *optional* input cost, or a variable "yeild boost" cost.

In my area for example, water costs $45/acre, 1/2 paid at the start of the irrigating season, 2nd 1/2 paid at the end of the season. Don't pay?  no water=no crop. pretty simple. I'm sure many areas like  California are paying $100/acre or more for water, which is a non-variable cost. That cost(s) is just for the water period. It does not include any delivery system, and labor to get that water to the plant.

To give you an idea of the different weather conditions,, in my location I think we've had something like 1- 1 1/2 inchs of rain since July.  How much moisture have you received in that same time frame ??