A recurring question among growers at this time of year is when to modify irrigation and even when to stop irrigating cherry orchards. Although it is a task that still has several weeks to go, the question is gaining strength as weather reports predict that high temperatures will once again extend well beyond the summer season.
Although it is during the postharvest when important processes take place in cherry orchards, such as root recovery, floral differentiation and the accumulation of carbon and nitrogen reserves; in this period, that is to say between 90 and 120 days after full flower (DDPF), the management of nutrition and irrigation is fundamental, being in this last task, a correct distribution of water is more relevant than the amount supplied.
However, it must be understood that there must be cultural changes in water management as clear signals to a process of acclimatization of the plants to enter the dormancy period in a more optimal way. The Technical Director of Avium and specialist in cherry production, Carlos Tapia, is emphatic in highlighting the relevance of a correct decision regarding modifying, maintaining or perfecting the irrigation system of a post-harvest orchard.
“In the acclimatization process, one of the important factors is managing irrigation; March should already be a month of transition from the point of view of irrigation implementation and we should already be lowering the replacement by around 60-50 percent of evapotranspiration, to eventually finish irrigating on March 31, except in soils with very little water retention, very sandy, which we are giving them perhaps 10 more days. This is the first signal that we can give to the plant, with a 30-day phase so that in April it begins to acclimatize prior to entering dormancy. In the case of orchards in formation, less than a year old, the water can even be stopped earlier, from March 15 to 20,” Tapia explained.
For his part, he highlights: “The correct management of irrigation at this stage is an objective that we must meet to complement the physiological changes and thus give clear signals to the plant that it begins to acclimatize to the season and be able to give way naturally to the growth process. leaf fall naturally, as the focus objective of this operation. Once we reach that objective of achieving 40 or 50 percent of the leaf fall, which could be recognized as the beginning of real or physiological dormancy, the soil’s water status must be permanently tested, because in autumn we necessarily have to to irrigate again, pointed out the Director of Avium, Carlos Tapia.
Finally, the specialist mentioned a quite frequent error in irrigation management and that is related to the high temperatures outside the summer season, a situation in which many producers question whether or not to resume said work: “We were very scared and we tend to react wrongly to the high temperatures of late summer and early fall. -April 30 is coming super hot, therefore I am going to water again-, that “super hot” is often maximum temperatures that can last a few minutes; if I have 30ºC on April 20, they will not last the same as 30ºC on January 15. The important thing in this is that the water demand is governed by evapotranspiration (Etc = ET0 x Kc) and the replacement is based on this and not on the rises in high temperatures each day, concluded Tapia.