The answers to most of your questions will vary from farm to farm, but I can tell you what we do.

1: Most guys farm straight back and forth, we farm in a circle. Bouncing over sprinkler tracks sucks. Once we get to the inside two tracks we switch to straight rows; partially because the curve gets too tight to easily keep check rows accurate, and because the closing wheels on the planter won't follow the openers when turning sharp.

I'm not sure what you mean about the sprayer question.

2: I haven't seen a lot of chemigation in my area, but I'm sure there is some. It's generally easier to spray any chemicals on (faster too). We sometimes run fertilizer through the sprinkler, though. It's a good way to give a crop an extra shot of nitrogen. It's a hassle getting fertilizer to the pivot, though.

3: Since I'm on vacation I don't have any notes handy, so I can't say how many acres an end gun adds. It depends on the size of the gun and the length of the system, though. Personally, I think end guns are a tremendous waste of time. I hate seeing water being sprayed into the air where it can evaporate. I also haven't seen good corn under an end gun; they just can't supply enough water to make those few extra acres yield well.

4: I know of only one corner system in my area. It looks like a pain in the behind. I don't know what kind of maintenance they take, but since they're so rare I'd say they aren't very cost effective.

5: Corner systems are nozzled like the rest of the sprinkler, so if it's nozzled correctly it should apply the same amount of water as the main system. They do waste a lot of water, though, when they trail behind the end tower. End guns are much more inefficient, with the application rate highly dependent on weather conditions (wind and heat).

 

My fields I farm in straight rows but I have tight soils. So I don't have any wheel ruts. The endgun adds about 110 feet to the end of my machine. When I look at my crops you can sure tell where the endgun stops. But I think that it all depends upon a lot of variables, on crop, weather, and soils. I see a lot of corner machines in Idaho on the potatoes so they must be worth having.

 

1. We plant in straight rows. We use a dump valve to water the corners of our square fields and where the slope allows.

In the lighter soil we plant straight but just where the pivot hits in a circle.

2. We put on Nitrogen through about half our pivots. It is very accurate. A lot of people are putting on fungicide through them, we haven't done that yet.

A benefit of being able to chemigate is that it is possible to easily add a nutrient late in the season.

3. I would take a stab and say an end gun gets you 20+ extra irrigated acres. We put booster pumps on some older pivot end guns and gained around 5 acres.

You can program pivots to shut off the endgun at points where it would hit a road or something.

4. We have a corner system. I suppose over time it pays for itself but they are expensive. We bought a quarter that already had one on it. We really haven't had any problems with it. Ours adds around 20 acres.

5. Each nozzle on the corner system has a valve and is able to be programmed to shut off, so when it isn't extended and is just trailing, only a couple of nozzles are on.

 

We run 14 pivots and 13 have corner systems. The reason is we farm in an area where land prices are high and the soil is fairly light. If our corners dont get water then we dont get much of a crop.
Also we grow some specialty irrigation crops that pay well. Being able to contract 155 acres rather than 130, pays for the corner system fast.
However, they aren't without problems. Out of all of our pivot downtime, over 50% have something to do with the corner system

 

Based on what I see around Lubbock and West Texas most people lay out the pivot in circle rows. Some will switch to strait rows around the last two towers but some will plant in circles all the way to the center mainly due to the fact that most farmers run a single press wheel on their planter. As far as fall back with a sprayer boom I have seen times when it has been a problem with the new bigger self propelled rigs but we have matched 12 row patterns and only a 12 row boom so no problems for us.

We also use chemigation / fertigation and we are pleased with the results we get from it. The only problems we had was figuring out the correct setting for the pump for our 1/2 mile pivot. The two smaller ones were easier.

As far as an end gun we don't have enough water to even consider this as an option. We are lucky to get what we can as our water table is dropping off every year. Also swing arm systems are hard to find here. The dealers I have talked to say there are a few but it is extremely rare.

I hope this helps give you some information on how things are normally done here in West Texas.

 

Here vegetable crops like carrots, cabbage, onions and lettuce are planted straight because of harvesting issues, corn, sugar beets and pinto beans are planted and harvested in a circle so equipment doesn't have to jump tracks.

We have almost every soil type, from blow sand to black tiger crap. In one circle/quarter you can have one extreme to the other in soil type.

 

As far as the cost of the corner arm, we have a 5 tower Valley with corner arm. The corner arm actually doubled the cost of the pivot, but in that cost is not only the structure but also the wire that must be buried the entire perimeter of the pivot for the arm to follow. So far we haven't had to do anything on that pivot but clean out nozzles, of course it's only 5? years old i think.

 

We have a pivot that we have to unplug nozzles on because of the rust. There's a vein of rusty water that goes through the area. We need to get rid of the drops and put some bigger nozzles on top.

 

Hi - I farm a few center pivots and we farm the field in a circle expect the inside two towers. Also, with the exception of the corner system tracks being irregular, the corner system has been great for us.

 

The newer corner systems are guided by GPS, at least the Reinke does, so no buried wire for the gophers to chew through. The ones around here seem to work well.

 

I have the pleasure of being a serviceman for a somewhat large dealer. In our area there are well over some 1000 pivots to service and deal with.
Very few plant in circles here. There are dry corners that they will curve to on the end however.
Not many chemigate but many fertigate. Its rather easy to set up injection pumps and the uniformity would be that of the sprinkler package.
The endgun added acreage depends on the length and endgun type. Added distance can range form 60 - 120 feet on the end. It does tend to help the transition out of the corners but by no means will catch it all.
Swingarms are very common here and I have logged many hours in repair. They will increase the amount the machine will be serviced. There are many moving parts to contend with. Then the buried wire can be damaged by lightening or rodents. But to there defence there are machines that we put up and never go back to and some that you can't seem to make work if you stood on your head. We have some of the originally made swing arms here that are still running from the early 80's we also have some center pivots from the early 60's. Somethings can help like the gps guidance they tend to eliminate a few issues.
As far as uniformity of application the endguns can vary some wind will effect them more. On our more sandy soils you can see the differences in the corn easily. Where the endgun doesn't reach corn goes from 10 ft tall to 4 in about 3 ft but from there back it's rather even. I have done testing with uniformity and you can have your endgun set right and set wrong with the angles of travel.
The swingarms can very. There are different ways to control the sprinklers. Std swingarms use cam stacks to trigger switches to control the valves. Then you have the computerized valve controls that have more "zones" or sets of sprinklers to be controlled at once. This all comes down to the swingarm can be as uniform as the parent machine if setup right. And if not you can see it. There are other things to help this out such as pressure regulators on the sprinklers and variable speed pumps that will match a constant pressure.
Hope this will help.