We got a Rodentator gopher blaster when they first came out in 2000, I think. I used it for a year or so, then loaned it out to some neighbors. We have it back in the shop, where it sits, mostly unused.

The issues in dealing with it might be unique to Nevada, so judge for yourself.

1. It does work as advertised. If you have a clear hole down to the pest you want to kill, and you fill the hole with the gases in the right proportion, you will kill the critter. You might even cave in their burrow/hole/tunnel.

I've killed everything from gophers to badgers with it. So it does work.

2. You need to adjust the mixture of gases before you go trying to kill stuff. My recommendation would be to find about a 3 to 4" diameter pipe, say heavy PVC conduit or pipe, about 10' long; lay this on the ground, away from windows and confined areas.

Get your eye and ear protection on. Always wear eye and ear protection when using these rodent blasters. And heavy clothes, especially heavy boots. You guys know I'm hardly a subscriber to the nanny-state "pad every corner" ideal, but you're creating an explosion here, and it is not easy to predict where stuff is about to fly. You might want to wear a broad-brimmed hat to keep dirt from getting in your scalp and down your collar.

You use this as a test blast chamber. The way I tend to do it is get the propane valve open first, then keep adding more and more oxygen until you start to get a "whop!", then a "pop!" and then you'll start getting a "wham!" out of test shots in the pipe. When you get it right in the 3 to 4" pipe, about 10' long, it will sound like a small cannon going off. 

When you shut off the valves on the blaster handle, make a mark on each of the gas valves and record how many turns it took to shut the valve from your ideal setting. Tweeking the mixture in a pest den hole is possible, but setting the gross mixture is very difficult in a non-ideal hole. 

3. Now you're ready to kill sumthin'. Go to your woodchuck, gopher, etc hole. Start out by putting in about 10 seconds flow of gases. Hit the igniter. You will have one of three results if you had the gas mixtures right:

- too little gas - you get this entirely unsatisfactory "pop" and you know darn well the critter isn't dead.

- just about right - you got a very satisfactory explosion that shakes the ground and leaves you standing upright.

- too much gas - you're covered in earth, your hide is hurting like you've been wihpped, your feet hurt like hell. Oh, and the ground under your feet disappeared into a cloud of flying dirt.

As you learn more about your particular pest, you'll start having a better idea of how much gas to start with. When we first bought the blaster, the manufacture recommended "oh, about 30 seconds" of fuel for a ground squirrel hole. I am here to tell you that 30 seconds of propane+oxygen down a squirrel hole will cause you, the operator, nearly as much pain as you're trying to cause to the squirrel. It is way, way too much gas for our squirrel holes. Remember what I said about study boots? If you're wearing sneakers or skimpy shoes and you put in way too much gas into a gopher or squirrel hole, you will regret not wearing solid shoes for the rest of the day. 

4. These things can start fires. Here in Nevada, we have lots of fine-stemmed fuels in the form of grasses. Our local ground squirrels pack quite a bit of cheatgrass and other fine seeds and chaff down into their holes. When I've used the blaster, especially near the edges of our farm, I've seen tufts of flaming cheat come flying out of the ground 30+ feet away, across a fenceline, and land in sagebrush and weeds. The last thing I need here is a bill from the NDF or BLM for fighting a wildland fire I started, so we don't use the blaster that much any more. Most of y'all live in areas where you don't have our particular fire issues, so use your own judgement in your local area.

I had a hard time spending 2500 for one of those things too so I rolled the cutting torch out of the shop.  Light the torch and set it like you were going to cut metal, then snuff out the flame.  Put the torch in the hole and count to ten or so, remove torch, light torch, then run the flame over the hole.   BAM!!!!!!  For best results do it right after it rains, ground is saturated and won't absorb the acetelyne.  You'd be surprised how far a mole run will go.

Like said above, wear eye and ear protection.

We call those a "gopher getter" or "burrow builder." Used at the right time of year, they're very, very effective. The bait we use here is oat bait, with 2% strychnine and maybe some cane sugar dust mixed in to get them to eat more of it. When I've used a gopher getter, I make passes between 25 and 50' apart, depending on the gopher mound density. I've gotten up to an 80% kill rate.

Best time of year here in Nevada to use it is in April, when the frost comes out of the ground, but there is still enough moisture to hold the burrow/tunnel open before irrigation season starts.

If I had a big infestation of pocket gophers to clear out, a gopher getter and 2% strych bait would be my first tool to use. 

I've often thought the exact same thing -- NH3 would do a heck of a job on ground-dwelling critters. And since we are growing so much more grass retail hay, we need more N in our fertility programs.

Can you guys in NH3-using country tell me some numbers/issues with NH3 knives, implements, nurse trailers, costs of equipment and the N (per unit) etc?

We have literally NO NH3 infrastructure here, so we'd be starting from scratch.

A Yetter or Dawn Equipment or DMI and a tool bar works. You will need a coulter to cut the roots and stuff, then a thin knife to inject the gas under pressure. If you need phosphate you can mount a tank on the bar for 10-34-0 and some kind of pump. No need for an exotic pump as close is good enough. One idea with putting the liquid phosphate down with in the same slot is the ammonia protects the phosphate molecules from calcium and magnesium and slows the converting phosphate to insoluble calcium and/or magnesium phosphates. The folks who worry about those things tell us liquid works better than dry phosphate in calcareous soils.

Speaking from my experience if you inject the AA when the air and ground are cold, below 50^o, a closing disk or packing wheel is not needed. If the temperatures are above the magic 50^o you will be running in front of a white toxic fog. I suggest using a closing disk.

Jim at Dawn in all his communications talks about needing a set of trash wheels to clear the trash. Not needed. For some reason he did not grasp the idea this is going into a solid grass sod, and we do not need or want a clean strip.

There is a system that squirts anhydrous down behind the opening coulter. From what I have seen this requires a pump to insure the needed pressure to get the AA down into the slot.

The what where and how of application depends on your soil type. A high pH is one consideration and cation exchange capacity is another. If you have a clay of clay loam one application of Nitrogen each year works just fine, if done while it is cold. I ave used 30" spacing and that works just fine. When I scab together a new tool the AA will be on 42 inch centers and the liquid will be on 21 inch centers.
If the soil is a sandy loam then multiple applications each year is appropriate, as ammonium, which is also a cation, will not have clay to attach to and become a slow release fertilizer. In the more sandy soils, less than 20 meq/100g CEC value, the nitrogen will be mobile and move out of the root zone with moisture.

Anhydrous does require some exciting infrastructure. It will be less costly to use liquid N, 32-0-0 or 28-0-0. This stuff works better if banded. Ideal is to band it behind the coulters. Forget using the knives. Save on the HP per drop and works just as well. Second best is to surface band the liquid, or dry nitrogen fertilizer.

Liquid or dry 30 or 40 inch centers works just fine. May not be as pretty as a picture but the bottom line will look good.

Figure 50 lbs/ton of hay for 12% CP hay. AA is 82% and UAN is 32% 30% or 28% depending.