ISSUES ABOUT VAPOR, INJECTION AND ORIFICES

There is a lot of uncertainty as to how much anhydrous can be injected with the currently available openers and knives. Application rates go from 30 lb. of N per acre at 4 mph for wheat to 280 lb. of N at 10 mph for corn.

We believe that "mole" knives made by Hi-Pro Mfg. of Watseka, Illinois can incorporate the highest rates. But many farmers can't use mole knives, either because of the horsepower requirement or because of soil disturbance. Various mid row banders and disk openers can be used, but they are probably not as effective as "mole" knives at the highest rates. Dawn Equipment and Yetter have some new designs which are worth considering. The trick is to incorporate as much of the vapor as possible since vapor tends to blow away. The correct method of tillage at the opener is key. We have both Yetter and Dawn dealers in our dealer network. Both have seen excellent results last Fall and this Spring.

This Spring aNH3 had two experimental bars operating in Illinois, each with 12 rows of mole knives for strip till and 6 Yetter openers for split side dress. We simultaneously generated the strip mounds with a small amount of anhydrous as starter while applying the bulk of anhydrous as split row preplant side dress. If you apply just before or when planting, you want to keep anhydrous away from the seed.

We are often asked about the effect of placing orifices at the ends of knives. There are no patent concerns about this method but we do not like it. The high velocity may cause the vapor to bounce at the point of impact. The small orifice creates a high velocity stream of liquid and vaporous anhydrous at the exit. The stream of anhydrous exiting the orifice is from 10% to 20% vapor by weight, dependent on the temperature in the nurse tank. But the volume percent of vapor is over 99%.

TO SEE A DISCUSSION AND GRAPH ABOUT RELATIVE VAPOR AND LIQUID VOLUMES › visit anhydrous-applicator.com

One other problem with having orifices at the ends of the injectors is the elimination of a pressure difference to measure flow through individual lines. For gauges to sense flow, the pressure after the orifice must be considerably greater than atmospheric.