Therefore, many companies have developed either super coolers or heat exchangers to convert the chemical into one constant state beore metering, this insures an accurate application rate. Anhydrous Ammonia System. This technology is based on the fact that green plants reflect solar energy in the near infrared wavelength, while soil, dead vegetation and litter do not. Individually these two measurements are hard to consistently quantify for a given location and plant type. However, radiance may be expressed as a percentage of irradiance, this is known as reflectance.
Reflectance remains constant for a given plant type in a given location.
From this knowledge field equipment has been developed that senses reflectance. The radiance and irradiance sensors connect to a computer, which calculates the reflectance and then decides if a green plant is present. If a plant is detected the computer sends the signal to spray. The time to spray is almost instantaneous. This system has been reported to save considerable money due to savings in herbicide applied.