Planting and replanting

Deciding to invest in an agricultural project has always been challenging, especially due to the various factors that must be taken into account to carry this out successfully.

The challenges are not only related to climatic and commercial factors, but also to technical factors. In this sense, some key aspects are variety; the rootstock; and driving system – these will depend directly on the climate, soil and the objectives that you want to achieve.

Knowledge of the orchard

To begin and determine the next steps, it is key to fully know the place on which you will work; To do this, a complete study of the soil must be carried out (effective depth, physical and/or chemical impediments, textural, chemical and biological analysis) and a agro climatological study, in order to have the greatest amount of information to make the best decisions according to your reality and conditions. One common mistake is taking neighboring projects as a reference.

Within the analyzes that today can be used to complement the empirical and “casual” there are several options such as the use of electrical conductivity maps, where the different imperfections of the soil can be visualized in depth; uses of drones for planimetry and images; and even complement it with satellite images through the use of multispectral images and orthophoto so you can have greater knowledge of the soil.

However, this does not culminate with the in situ analysis in each orchard. Through the use of spatially distributed pits so that they are representative, all the details are brought together for decision-making, such as rootstock to be used, planting density, planting direction, use of terraces, need for drainage, etc.

Photo 1: Variability map of soil electrical conductivity and pit analysis.

1. Replanting projects

For those who must replace old plantations, in addition to what is described above in terms of analysis, it is very important to focus on possible problems that could affect the normal development of a replanting project.

  • Presence of soil larvae.
  • Presence of nematodes (also known as roundworms or eelworms). Gender and severity if present.
  • Presence of fungi and bacteria. It is very important to be able to perform a specific analysis for the pathogen that needs to be found, if it is present.

These concerns should not only be kept in mind in a replanting project, but also in a new project to start with as much information as possible. This will define what management must be carried out prior to planting, such as possible fumigations, application of organic amendments, and application of phytosanitary and biological products to prevent future problems.

2. Variety/rootstock selection.

As a first step, the best variety must be defined according to the weather where the orchard will be established, determining the chilling hour requirements for each variety.

For example, for early harvests, consider varieties that can perform commercially before. On the other hand, in a colder area it will be advisable to focus on varieties that allow the harvest to be extended. While in intermediate areas, it is recommended to look for varieties that can be competitive against the large volume of fruit at the time.

Once the variety to be planted has been selected, it is important to choose the rootstock that will accompany it, combining both the type of soil and the variety/rootstock combination, which translates into the use of varieties with greater fruit set together with rootstocks with greater vigor (Figure 1), and varieties with lower fruit set with rootstocks of lower vigor to achieve a technical balance between fruit and leaves – known as the leaf/fruit ratio (Figure 2).

Figura 1. Vigor y Fertilidad de los distintos portainjertos.
Figure 2. Leaf/Fruit Ratio.

3. Choice of management system.

The driving system will be determined by three main factors: the way of working that best suits the product; the variety/rootstock combination; and more efficient systems in the use of labor, the latter being key to maximizing worker productivity. The weaker the combination, the greater the focus on the central axis, considering not to abuse diluting a predetermined vigor according to the characteristics of the site to be planted; while, the more vigorous, the greater the tendency towards vigor dilution systems, such as Y-Trellis or KGB driving systems.

For example, for very water-retentive and clayey soils, the Colt rootstock is the one that best suits, while in lighter soils the MaxMa 14 or MaxMa 60 series could be an alternative; In the case of loam to clay loam soils, the Gisela® series conditioning Gisela® 5, 6 or 12 could also be an alternative. However, the Colt rootstock is the one that adapts to any site and any soil condition, not just any variety.

4. Choosing the right plant

Finished Plant

Probably the plant format that provides the most security in a planting project, consists of a plant raised in a nursery after one year of rootstock establishment and another season of variety development. Logically, it is the one with the highest cost and, at the same time, without a doubt the format that has the least administration once planted.

Bare-root plan

Rootstock developed in the nursery to achieve a minimum graft diameter at its base of around 8-9 mm – for approximately the month of February/August, depending on the hemisphere.

Once this objective has been achieved, bud grafting (or patch) is carried out at the base of these plants from material harvested in the season. In general, two patches are used to ensure catch in spring. The acceptable quality of this type of plant is the diameter at the time of delivery, which optimally should exceed 8 mm. of base diameter.

Plant grafted in soil

In recent years, the way of establishing the plantation has been changing and one of the good experiences in practice has been through the use of one-season rootstocks raised in a nursery and grafted in the ground, through spike grafting in winter. 

Rootstocks must be at least 8 mm. in diameter at the base so that it is of graftable quality, mainly so that the diameter is in accordance with the grafting material. This last point is important at the time of quality control of the grafting.

Container or bag plant

Rootstock established directly in the container or bag on a substrate or mixture that allows rapid establishment of the seedling and subsequent development. They aim to reach graft diameter by late summer and are a safe option when establishing rootstock seedlings late in the season. 

These plants can be grafted by dormant eye in summer or by spike in winter, depending on the nursery’s strategy, often in common agreement with the producer depending on the establishment of their orchard.

5. Establishment

Continuing with the chronology for the development of a new project, special care must be taken at the beginning of this:

  • Soil preparation

A task that has become more important over time due to its real impact on the productive potential of a garden is the preparation of the soil, understanding that it is not only about the physical, but also the chemical and biological – these are the components. those who together will define our future.

The work of preparing the subsoil and the arable layer aims to break the physical impediments of the soil, encourage root exploration, ensure good drainage and increase the water retention capacity in the profile to promote good plant development to achieve our ultimate goal of potential.

To prepare the subsoil, the correct choice of machinery will depend on the type of soil, humidity and its physical limitations.

To advance the arable layer (first 30 cm), harrows and chisel plows (called Jympa) are used to break up the soil into smaller parts. It is at this stage where we can make chemical corrections through amendments and then build, if necessary, ridges or platforms, either to seek greater effective depth of soil or just as an alternative to promote correct drainage of runoff in winter. 

  • Plantation

This stage is very important, since it is also carried out only once in the life of the project, therefore a suitable hole must be found so that the roots remain loosely, without rolling them or in the opposite direction to the ground, using the help of a small lift of the plant before finishing covering the hole and very well plumb perpendicular to the ground, seeking better plant development.

The above can only be carried out as long as the irrigation system has been completed, tested and is working, since with the tendency towards low rainfall, the risk must be assumed, watering before and during the process of planting a new project.

  • Formation

The formation of the project consists of three stages; the first, where the base of the “skeleton” of the plants is built, whether it is one, two or several axes.

The second stage will be to complete the “skeleton” formed the first year, branching the plants using different strategies to obtain the so-called “mother branches”, a key stage for the success of the project.

Finally, in the last stage, the “balance” of the branches within the plant is sought, analyzing the scenario in winter and carrying out the first initial renewal pruning, eliminating the very vigorous ones.

It should be noted that the stages and processes described above are fundamental when embarking on the creation of a cherry orchard model, since each orchard has unique characteristics, both in type of soil, rainfall, among others, all determining aspects for the success or failure of a new planting project.

Regardless of the training system used, a cherry orchard must have a productive potential of a minimum close to 12 Ton/ha to be competitive. However, to reach this number and maintain it over time, many tasks must be carried out in the project formation stage. After that, the maintenance and reproductive/vegetative balance is the fundamental basis of this productive potential.

After this, in what type/age of wood should I have the fruit centers to have quality fruit and production potential?

The quality of the fruit is defined by the leaf/fruit ratio of the tree, and also by the capacity of each fruit center (dart or one-year twig base) to feed the amount of fruit it contains. This capacity is greater when the darts are inserted into a branch section of an optimal diameter.

However, the thickest branches within a plant tend to favor the vegetative part and begin to branch excessively, especially when they have been heavily intervened in winter pruning. For this reason, the most important thing is to handle the concept of balance in trees, that is, we must form a tree with balanced branches, eliminating both extremes, the very thick branches and the very thin ones.

It is very important that all this analysis begins to be done once the garden is established, since the success of completing each of the stages of the project depends on these tasks.

Going back, when establishing a new orchard the following should be considered:

First stage of formation

After planting the garden, the most important thing is to promote the base of the “tree skeleton.” If it is an axis-based system, it must be achieved in that season to develop the best axes, with over 2 meters in height, good buds and internodes, and (in some cases) without laterals that can “over-develop” the following season and go against an optimal balance.

Any intervention on the developing axis in the first season, that is, early branching, is a sign contrary to root development. This is how axes intervened in green with the aim of advancing branching -wrongly in many cases-, ending up with very heterogeneous orchards and with their roots not fully expressed during that season.

To obtain these “good axes”, both in a central axis and in its variations it is essential to develop them in the orchard from 40 or 50 cm., due to this it is recommended that the orchards established from a finished plant are reduced at the time of planting. This is how you start with a fully rooted plant and with a “0 kilometer” axis.

In KGB, however, this base of the “skeleton” is the crown from which all the branches will emerge. This crown must be well illuminated so that in the future the garden allows it to continue reproducing branches.

Photo 1: Axis developed in an orchard, objective of the first stage of training

Second stage of formation

After finishing the initial stage and ensuring a good primary structure of the trees, the objective now is to complete the “skeleton” of the plants, which means obtaining the structures that will give way to production. Generally we talk about “mother branches” where the future fruit centers will be housed (especially darts) and which should not necessarily be permanent, but rather it is estimated that they can complete a productive cycle and then be renewed.

Branching work is a critical point in the formation of an orchard, since it is essential that a minimum number of branches be generated with a development of at least 70-80 cm. in length, and ideally from 50-60 cm. axis height.

Within branching techniques we can find different ideas and procedures that allow trees to branch and obtain this structure. Without going into detail about which of the techniques is the best, the most important point in the branching process is supervision.

The most important thing is the formation and development of the orchards, which partially defines the homogeneity and production potential of the project. The great and most relevant difference between the success and failure of plant formation is the lack of analysis and supervision that must be done permanently from the beginning to the end of the branching process.

A well-branched tree is one balanced from the beginning. In spring, when these lateral growths begin to be defined, it is advisable to at least reason about the procedure and need for orthopedics, where many times you can begin with the toothpick posture and end with the tying of already developed branches towards the end of summer . This will allow you to begin “balancing” the tree to promote its early entry into production.

Third stage of formation

When the skeleton or permanent structure is already defined, the most important thing is to identify the balance of each of the plants, which is already analyzed in the following winter.

This analysis is done from the critical point of view of the structural balance, so that all growth that is above this “balance” is eliminated. The elimination of over-vigorous branches, considered as initial renewal pruning, is to leave a “stub” that allows new growth with a vigor in line with the average of the plant.

This point is applicable to all conduction systems, since in all of them we must maintain a balance between the branches that are forming the plant. It is important to analyze the balance in each section of the plant, since a branch of medium vigor in the lower part is probably vigorous in the upper part, and must be eliminated to maintain this balance at the top, where we need better control of growth to allow the entry of light.

Throughout the productive life of the orchard, it is very important to maintain this concept of “balance” by renewing branches, since we must base production on young darts, which are those that could maintain a high potential. However, the above is under constant study by different specialists and there is still no consensus that the older the dart, the lower the quality of the fruit.

Finally

Regardless of the age of the orchard, visually it should always look “young” with vigor, healthy darts and balanced branches that provide very good quality fruit. It is under this vision that we must speak of “permanent renewal” and not of a technique. It must also be considered that this concept of balance, which allows the structure to be in constant evolution, is manageable from the year of branching. Once the plants enter a productive state -and often in a vicious cycle of very vigorous branches, shade and wood wear-, renewal is not always safe and successful.

Finally, this renewal model fits seamlessly into all existing conduction systems, from a traditional central axle, Y-Trellis, Tatura, axles to higher density, and with greater importance in training models such as KGB and UFO.

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