Due to the fact that sprinkler irrigation systems run along a single trajectory for a long time, especially on soil types with finer texture and higher compaction such as clay and loam, it is easy to form ruts. Deep ruts (over 15cm) can trap sprinkler irrigation systems for a long time, leading to motor burnout and equipment shutdown.
Changing the position of the nozzle, that is, placing the nozzle at the back, is a good solution. Today we will focus on introducing other functions of the rear mounted sprinkler head. This design is rarely used in the operation of sprinkler irrigation machines in China, but is very popular in farms in developed countries such as Europe, America, and Australia.
Literally speaking, placing the nozzle at the back means moving it away from the center of the sprinkler’s main pipeline. As the equipment needs to rotate in both forward and reverse directions, the nozzles are scattered on both sides of the main pipeline, as shown in Figure 3.
Of course, not all rear mounted nozzles require a metal support tube. The simplest form can also be to place the nozzle hose on the tension bar, as shown in the figure below. This is actually a form of dispersing nozzles.
In addition to the effect of placing the nozzle back on improving the rutting of the sprinkler system mentioned earlier, the maximum function of placing the nozzle back is to reduce irrigation intensity, decrease surface runoff, and alleviate the impact of nozzle spraying on the soil, thereby forming soil compaction.
We all know that as the length of a pointer sprinkler increases, the irrigated area becomes larger, which requires an increase in the flow rate of the subsequent nozzles (Figure 5), resulting in an increase in irrigation intensity and soil compaction. However, the soil infiltration capacity remains unchanged, and the higher the irrigation intensity, the more water will be unable to infiltrate in a short period of time, leading to an increase in surface runoff. In order to reduce this phenomenon, many users like to increase the speed of the sprinkler system. However, if the speed is too fast, the rainfall of the sprinkler system will also decrease. If the local evaporation is high and the rainfall is reduced, it will lead to more floating losses.
By placing the nozzles at the back, the overlap between the nozzles remains unchanged, and the irrigation amount remains the same. However, the spraying area increases, meaning that water is sprayed to more areas, reducing irrigation intensity. This increases soil infiltration time, thereby reducing surface runoff. Here are a few pictures to illustrate.
The following image can more intuitively show the difference between the rear mounted nozzle and the ordinary layout of the nozzle. It can be seen that the function of the rear mounted nozzle is very important.
