Drip irrigation is widely used in the fields of market gardening and horticulture. New experiments have shown it is also of interest in the domain of field crops.

Primarily economic benefits

The benefits of the drip irrigation system are primarily economic ones. Its principle of low pressure is synonymous with low energy consumption and low water consumption. The efficiency (calculated from the ratio of the amount of water available to the roots of the crop and the amount applied by the irrigation equipment) of surface drop by drop (DBD) is 98%.

Agronomic benefits:

But arguments for drip irrigation are also agronomic, allowing the supply of water closer to the plant roots without wetting the foliage or the plant (avoiding diseases) without the influence of wind. The technique also helps to bring nutrients to the plant regardless of its stage of development. Finally, once installed, the drip system is not very labour-mobilizing.
Finally, the flexibility of the system is almost endless: We can plan irrigation flow rates, schedules and irrigation cycles based on seasonal and daily variations of climatic conditions and the type of crop, in order to reduce water consumption to the maximum.

Surface drip irrigation

Surface drip irrigation (also known as drop-by-drop irrigation, trickle irrigation, micro irrigation or localized irrigation) consists of a polyethylene pipe, inside which has been implanted a pressure compensating dripper. Its implementation is easy, since all you have to do is place the drip system on the crop row manually or by machine. The investment is 1 300 to 1 500 € per hectare and the pipes are discarded at the end of the season.

Subsurface drip irrigation: an innovative solution

The subsurface drip (SDI Subsurface Drip Irrigation) is an innovative solution, powered by the latest generation of polyethylene tapes that can be buried to a depth of about 30 cm. These ducts are fitted with drippers (spaced from 40 to 50 cm, in general) with a flow rate which remains close to the nominal speed, and with good uniformity, when operating in the variation of pressure range (0.5- 2.5 bar) recommended by the manufacturer.

The innovative nature of this equipment is that it opposes the invasion of the drippers by particles of soil and roots. In addition, the emitters are provided with an anti-siphon system and the tape empties automatically as soon as the water is cut. These features differentiate them from the systems tested more than twenty years ago, such as porous pipes. Finally, according to the manufacturers, the lifetime of SDI would be about twenty years. In the event that this period may be actually reached SDI surpasses largely, from an economic point of view, wheel line system. The investment for buried drip equipment ranges from € 2,500 to € 4,000 per hectare.

In addition, SDI allows simplified field tilling techniques without having to remove or move the equipment as is the case with some full coverage sprinkler systems and even the reel system.

Drip irrigation, long confined to vegetable crops, now finds its place in major field crops. The example comes from Italian producers who face more expensive energy bills than ours and who have been using this technique for ten years for their wheat and corn. Installations were performed by Martineau-Irrigation (ICS subsidiary) in Charente-Maritime, on plots of 30 to 150 hectares.