Center Pivot Corner Arms – How Do I Cover My Corners?
When our forefathers began mapping out the land in this great country, they chose square parcels instead of round ones. When center pivot irrigation was developed, walking around a fixed pivot point in a circle was more efficient. Since then, we have been trying to figure out ways to water the corners. Although linear or straight-line systems have been developed, they are generally more costly than the center pivot system.
The corner arm system has a steerable drive unit that can be guided to extend or retract depending on the field borders. This allows the length of the last span and the overhang to be utilized to water areas that would normally be dry corners with a basic center pivot system. Because they move slow and are a bit clumsy, the transition from retracted and extended takes a significant travel distance to occur. A guidance system must be utilized to steer this part of the machine. For years we have used buried wire to transmit a signal to the steering unit. Today GPS guidance is available which is much easier to change and generally simpler to fix.
This machine adds acres in all 4 corners.
With nearly every field having some corners, we often wonder when does a corner arm make economic sense to add to my system. Like many questions, there are several variables. How many watered acres will the corner arm add to a system, is a great place to start? The value of your crop can be a significant factor, but we generally start with looking for at least 30 additional acres. The reason for this estimate is that because of the additional equipment to steer the system and turn sprinklers on and off will have a similar cost to adding a 40-acre base pivot to your project. Although corner arms have been improved several times, they are also still a higher maintenance item compared to a straight machine. Parking the machine when not in use is another consideration when including a corner arm in your center pivot design. When determining if your field is “corner arm” friendly, it is also important to consider topography. Hills and clearance can be more difficult to traverse when adding a steerable drive unit. When you have the right field and crop, adding a corner arm can be a home run!
The above photo shows a straight machine with a fixed gun watering the SE corner.
At Michigan Valley Irrigation we look for designs that best cover your fields and include the economics in those designs. A corner arm system can be a valuable tool for the right field layout, but there are other options. Some of those options might include another partial turn straight machine, a bender, or perhaps a fixed gun or two. Our goal on every project is to help you put water where you want it and when your need it. We would appreciate an opportunity to discuss the options for your farm.
