Post-dormancy bud nutrition
By Ian Carlo Bottinelli Wolleter - Agricultural Engineer - Plant Nutrition Specialist
At this time of the year it is important to begin to consider some physiological aspects of deciduous plants that will have a very high relevance in the budding and flowering phase: how is the tree prepared to come out of dormancy? Will it sprout vigorously and generate strong, differentiated flowers that set in a great way?
It sounds like a thousand factors and it is so; The factors that dominate the exit of the winter break are many and more than half are unmanageable, since they depend a lot on the climate and what happens in the dormant bud. In general, the strategy that every good producer must have is to check and prevent anticipating.
Checking implies knowing the state of the fruit wood, the level of reserves in it and the level of differentiation of the buds. In addition to checking the development of winter and predicting what the winter will be like.
In general, the two most important phases of dormancy or latency are:
Endolatency; during this phase the buds cannot sprout spontaneously and ends when the cold requirements have been completed. Endolatencia output is regulated by climate (cold hours) and / or exogenous elements such as Sprouting Promoters used in areas where cold requirements are not met.
Ecollatence is the phase where all the buds can potentially sprout, but remain at rest until the spring temperatures induce the appearance of green tips. This is the most critical phase, where more physiological problems arise and that will impact budding and flowering, for example bud necrosis and / or poor bunch differentiation.
The cold activates catalase enzymes, which uncover physiological processes in the buds. The base element of this whole process of breaking dormancy is Glutation.
The lack of winter cold in deciduous fruit trees and vines produces: Delayed sprouting of the buds, erratic sprouting, low number of buds, fewer flowers or bunches per shoot and therefore general lack of uniformity.
During the phase of Ecolatencia and later sprouting, the yolks and the bud obtain energy for their growth mainly of sugars of the same reserves of the plant. When the reserve energy is exhausted, the outbreak should begin its autotrophic phase, that is to produce energy from photosynthesis. This moment is critical in cold and cloudy springs, because if so, it is common for the outbreak to "Be chante", Appear filage, fall flowers, etc. The outbreak ran out of fuel and the plant is not able to supply enough energy.
This point is the cornerstone of a wide range of products "Biostimulants", energy inductors or "Anti-stress". This is the point that best supports the use of foliar amino acids and other types of nutritional elements.
In cold and cloudy springs and outbreaks with little vigor, according to the author's experience, the use of amino acids and compounds of high C / N ratio should be privileged; alone or in mixture with mineral elements that catalyze photosynthesis (Mg for example); this to provide external energy to the bud and inflorescences.
Although the use of cytokinins in green tips has been shown to help to even out the sprout, the use of trihormonal products, cytokinin inducers or synthetic hormones on the developing sprout is not very advisable, since instead of supporting the development of a sprout vigorously stimulates the appearance of new shoots that will compete for the few reserves that the system has left. Also in cold springs it is not advisable to start fertilizing very early, since the plant is forced to spend more energy absorbing the fertilizer through the roots.
In some countries of erratic sprouting product of low accumulation of cold hours, it is even used with relative success the foliar applications of cane sugar to deliver external energy to the outbreak ...
Some elements to consider in a strategy of prevention and anticipation of sprouting problems in cold springs:
- Favor a correct and early agostamiento
- Good and optimal postharvest, means feeding the sprout with mineral reserves and nutrients.
- Short and delayed pruning
- If you consider the use of cyanamide, never apply an even dose, you should consider the type of tree, variety, age of the garden, etc.
- Monitor arginine and sugars in roots and wood
- Applications of foliar products with a high C / N ratio which are a source of direct energy to the outbreak, ideally providing sugars, gluconates, amino acids, cysteine and organic acids in general.
- Refrain from the use of synthetic fithormonas or other elements that force the plant to additional energy expenditure
Needless to say, it is the right moment to sit down with your head counselor and strategically analyze what we will do in case A or in case B. In any case, it is certain that with a strategy defined with time the result will be better than the improvisation of the moment .
Source: Fruit Portal
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