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.