Water is a critical component in the production of watermelons, so the selection of the appropriate irrigation system, moisture register and establishment of the irrigation program optimizes the yield and quality of watermelon fruits. A ripe watermelon is made up of more than 90% water (a fruit of 14 kilos contains more than 11 liters of water). Therefore, adequate water supply is critical to optimize the yield and quality of this crop. Watermelons have the potential to develop deep roots (1.2 to 1.8 meters), but such depth depends to a large extent on soil conditions and cultivation practices.
The restriction on the depth of the roots and the fact that watermelons normally grow in sandy soils with low water retention capacity, make it necessary to use irrigation to obtain consistently high yields in many regions of the world.
The lack of water during the establishment of watermelon cultivation delays ripening and causes production lapses. In addition, drought in early vegetative stages produces a reduction in leaf area and yield. Drip irrigation has gained popularity in the cultivation of watermelon. You can use it with or without plastic padding, and one of its greatest advantages is the efficiency in the use of water, again, provided it is used correctly. Some studies indicate that this irrigation system favors a premature yield such as the size of the fruit.
Drip irrigation systems can help fertigation. This method allows to provide nutrients in the crop to a measure that is needed and eliminates the need for a fertilizer application early in the season, avoiding the consequent problems of excessive salinity.
The water used for cultivation and evaporation of the soil is called evapotranspiration (ET). ET rates have been reported in watermelons of 75 mm per day. The growth stage of the crop, temperature, relative humidity, solar radiation, wind and space between the affected plants at the rate of ET. Using soil moisture sensors to schedule adequate water sessions ensures that soil moisture is adequate to prevent water stress.
The irrigation program should be adjusted when soil moisture values are not very severe or dry conditions. Irrigation recommendations.
- From the plantation to the vegetative development, apply 13mm of water when the 15cm of the soil surface is dry (every five or six days in dry weather)
- From development to first flowering, apply 19mm every five days in dry weather. If it occurs, you should eat on the plants before noon, increase the frequency of watering.
- From the first flowering to the harvest, apply 25 mm every four days in dry weather. If the weather is extremely warm (more than 35 ° C), it would be advisable to increase the frequency to three days to avoid water stress.