Irrigate Crop According to Given Guidelines

Monitoring Irrigation Quality

In crop production, it is important to have a uniform irrigation pattern in all blocks. The entire root zone must be wetted uniformly. Regular quality checks on the system are essential to ensure that the prescribed standards are maintained.

While a block is being irrigated, a visual inspection must be done, focussing on the following:

Leaks – Any leak, large or small, must be repaired immediately using a suitable joint or fitting. Leaks that cannot be repaired must be reported immediately to the supervisor or manager. Close the infield valve that controls the flow to the irrigation block in case of a large leak or a burst pipe.

Dry Spots – While irrigating, one should always be on the lookout for dry spots. Determine the cause of the dry spot, which may be a clogged micro or dripper, or a faulty spreader. If the micro is blocked, remove the micro from the peg, remove the head and clean the nozzle. If a dripper is blocked, tap the dripper with your finger. If it stays clogged, report it to the supervisor or manager. Never use a sharp object to unclog the dripper as this will damage or puncture the dripper. Dry spots can also occur due to swivels that remain stationary, spreaders that spray skew or micros that have fallen over. Make sure that the peg is upright that the spreader sprays in the right direction and pattern, and that the swivels are turning.

Overlapping – Most irrigation systems have a small degree of overlapping. Be on the lookout for excessive overlapping on the one side of a crop and a dry spot on the other. Move the emitter more to the centre. Overlapping can also occur when the radius of the spreader or spinner increases, due to pressure being too high, which may coincide with misting. Check the pressure, make the necessary adjustment, and report the matter to the manager.

Over- and under-irrigation – Too much water is just as bad for crops as too little water. Be attentive to large puddles and runoff forming, which may be an indication of over-irrigation. Check that the pressure is not too high and that the stand-time is not too long. Under-irrigation will cause crops to wilt. Check that the pressure is not too low and that the stand-time is not too short.

Irrigation Scheduling

Irrigation scheduling determines the amount of time (stand-time) and water that each block receives, and also indicates the time allowed to change the valves. Scheduling varies between seasons according to the phenology of the crop.

The irrigation schedule is determined and prescribed by the irrigation manager. Keeping to the irrigation schedule ensures that irrigation is effective.

Remember that the stand-time and the time required to open valves vary between seasons and between farms. It is important to open the valve of the specified block at the right time and to close it at the right time. Failing to do so will affect the crop negatively.

Monitoring Operational parameters

Operational parameters are the parameters within which the irrigation system should operate to ensure that it functions effectively. These parameters include operating pressures, stand-times and the quality checks as set out.

During irrigation, these parameters must be monitored and recorded. Recordkeeping of these parameters is important, as this helps the manager to manage the irrigation effectively and to detect possible problems early.