In cherry production, post-harvest reflects the new start of the upcoming season, a period in which, in addition to having to keep the plants in good condition during the summer, they need to accumulate reserves in shoots and roots, which they will use for reproductive processes at the beginning of spring.
Poor execution during this period will lead to a deficient accumulation of these reserves (sugars and amino acids), which will have consequences in spring that will be reflected in the productivity and quality of the fruit.
We must consider that the cherry tree carries out its initial reproductive processes practically without leaves, so it has no help in being able to synthesize sugars for the preliminary development of the floral structures; for this reason, providing these reserves is such a priority if we want to have good productive and economic results the following season.
What does the plant need to accumulate sugars and amino acids?
In my opinion, the metaphysical foundations of plant behavior must always be considered in order to generate strategies, in addition to the diagnosis that can be generated on each property.
In order to produce sugars and amino acids, a plant needs to be photosynthesizing for as long as possible during the day; in photosynthesis, it will transform CO2 into sugars, which, when added to nitrogenous bases, will generate reserve amino acids. The big question we must ask ourselves is: What factors can alter the plant's full photosynthesis?
The stomatal closure that prevents CO2 from entering the plant is promoted by various factors such as high temperatures, winds, solar radiation, pests and irrigation and root problems, poor nutrition, etc. These factors must be detected for each field, since they all have natural peculiarities, even within a field there are differences depending on its geography.
There are many fields that experience strong winds after 3:00 p.m. and 6:00-7:00 p.m., which dehydrate the leaf blades, causing stomatal closure. If we consider that the average period of photosynthesis in the light phase is 12 to 13 hours and we have this condition for 4 to 5 hours in the afternoon, we will have a 40% of the useful day in which the plant will not be functioning well. In turn, solar radiation causes burning of the surface of the leaf blades, especially those most exposed to the sun; this can represent an additional 30% to the problem.
If we combine the above with temperatures above 30 degrees Celsius for 5 to 6 hours, we will see that at least we could lose 60% of the photosynthetic potential of the plant in the summer period. For these reasons, it is necessary to take special care in this period, because the productivity of the next season is being defined.
How to protect orchards is the next question?
Today, agriculture has countless technologies that help us overcome the adversities we face every day, as well as cultural practices that we must carry out in order to optimize the process.
Keeping gardens hydrated is of the utmost importance; keeping them well nourished and biostimulated will be basic keys to facing the heat wave to which we are exposed this summer.
In terms of nutrition, it is very important to be able to rely on foliar analysis in order to determine the nutritional status of the orchards and, from that point, to be able to define a good balanced strategy between all the elements, in order to achieve a perfectly nourished orchard, without providing excess nutrients, as well as not falling into deficient nutrition.
All nutritional elements are important, none can be missing for the perfect metabolic functioning of the plant, but in many cases we will have an excess of nutrients within it, such as Boron, Iron, Manganese, which should not be provided within a nutritional strategy. In the case of cations, it is important to determine the levels of Calcium, we must remember that the plant not only uses this element for the construction of fruit, but also for the construction and strengthening of vegetative structures. Calcium is closely related to the stomatal closure that was discussed in previous paragraphs, since stomatal closure is synonymous with a hormonal effect that generates a hyperpolarization of the membranes, where Calcium leaves the walls of the vacuoles, finally triggering the migration of Potassium from it and causing the stomata to close.
Potassium is a very important player throughout the period from flowering to winter break. Although it is a relevant cofactor for the movement of sugars, for functional factors it will be the element that will keep plant cells turgid, as was said about the stomata. In order to have open stomata functioning properly, we must necessarily have a plant with good levels of Potassium.
Phosphorus is a great element, but its central importance in the nutrition of a plant is often forgotten. We must remember that in the Calvin cycle (sugar formation cycle), all the steps are phosphorus-based. If we have a phosphorus deficiency, we cannot think that we could have an optimized production of reserve sugars.
In this way, all factors are intertwined, all nutritional elements operate as links in a large chain, which we cannot break in order to be efficient in generating reserves.
Biostimulation will be a key factor in the summer period, especially when we are facing high temperatures across the board; the use of biostimulants such as algae, amino acids, Glycine-Betaine, vitamins, will help keep plants better prepared to face biotic and abiotic stress factors.
Another important condition of the post-harvest period in cherry trees is the construction of new roots, in order to advance in raising the levels of root mass over time. Today, with the number of alternatives we have on the market, this goal is relatively easy to achieve, but it is extremely important to have a diagnosis of the soil reality, initial root level, rootstock, etc. If, for example, we have compacted soils, we cannot expect the roots to develop properly; the starting point must be directed at increasing macroporosis in the soil, otherwise the vicious circle in which an orchard can find itself will not be broken. If, on the other hand, I have a soil with a good level and balance between macro and micropores, the task is faster.
We must be very clear that the last winter we experienced, the soils tended to compact and due to this condition, plus the excess humidity, there was a general loss of root mass, a condition that must be regularized within the next 2 to 3 months.
Post-harvest accounts for a high percentage of cherry production; being methodical and analytical in this phase of cherry orchard management is, in my opinion, key. It is also important to remember that what is not done today cannot be compensated for in the spring.
