Drip irrigation improves plant health; by not wetting the aerial part of the plant, a lower incidence of fungal diseases is observed. In addition, onion is a crop sensitive to water stress and moisture variations, so drip irrigation, being a localized and high frequency irrigation system, is very suitable for maintaining constant moisture in the root zone and at the required depth. Constant moisture also results in a reduction of double bulbs, which increases the commercial value of the crop.
Frequent watering limits root development, which favors bulb thickening. The onion root system is very superficial, with 92% of water extraction in the soil occurring in the first 15 cm. Therefore, low-flow drippers are very suitable for irrigation of this crop.