Avocado productivity in new plantation
Avocado productivity in new plantation: The avocado ( Persea americana Mill) is a fruit tree of Mexican origin from the Laureacea family, introduced in Spain between the seventeenth and eighteenth centuries, although it was not until the mid-nineteenth century when its cultivation developed at a productive level. Currently, Spain is the only European producing and exporting country of this exotic fruit, serving as a gateway to the rest of Europe, although there is also production in Portugal, the Algarve, and testimonial plantations in Sicily and Crete.
The particular weather conditions that avocado requires to survive mean that its cultivation is limited to very specific places in the national territory.
And the fact is that the subtropical microclimate of these two provinces is ideal for the harvest of this fruit, which takes place between the months of November and May.
I would like to deal primarily with the topic of new plantations, as a “guide to success in an avocado plantation”. So I’ll start with the essentials. What edapho-climatic requirements must be taken into account before carrying out a plantation? And ground preparation? The main requirements have to do with the origin of the species in Central America and we can focus on temperature, rainfall and soil . In the avocado there are three botanical types commonly called races: Antillean, Guatemalan and Mexican.
The Antillean breed comes from the lower areas of the tropics and, therefore, is adapted to tropical climates and its cultivation is difficult in colder areas. The Guatemalan and Mexican races come from high areas of Central America and, therefore, are adapted to colder conditions. The varieties that can be grown in temperate zones belong to these two races and are fundamentally hybrids between the two. However, it must be taken into account that temperatures below 0ºC can significantly affect productionand, if they are prolonged, they can kill the tree. Therefore, it is not necessary to look only at the average minimum temperatures but at the absolute minimum ones. Minimum temperatures below -2ºC, even for a short time and not every year, can prevent avocado cultivation, although there are differences between varieties. In the avocado’s areas of origin, rainfall is frequent and the relative humidity generally high. Therefore, in drier conditions it is necessary to make contributions of water which, in the case of southern Spain, we can estimate at about 7000 m3 per hectare per year. Irrigation water must be of quality , since avocado is very susceptible to excess salts. As for the soil , ideally a Sufficient concentration of organic matter to avoid waterlogging and favor a good growth of the roots , which in the case of this crop, are very superficial.
New avocado plantations
Avocado productivity in new plantation: What should we take into consideration when choosing the plants in the nursery?
We must bear in mind that an avocado plantation is made with a time horizon of at least 20 years , so the choice of plant material is a fundamental criterion for the success of the plantations. You should always resort to trusted nurseries and choose a suitable pattern based on the soil conditions in the planting area . There are patterns with some tolerance to salinity or limestone, others with tolerance to Phytophthora cinnamomi and others better adapted to colder conditions.
Hass is the variety par excellence, but are there other alternative varieties with good commercial outlets?
There are hundreds of varieties of avocado. Hass is a variety that arose by chance in California almost 100 years ago and that has been established as a commercial reference for two fundamental reasons: the change in color that indicates when the fruit is ready for consumption (until the 60s of the last century the reference variety was ‘Strong’ with green skin and that does not change color when ripe) and good post-harvest behavior. However, in the case of Spain, where in addition to the local market, we supply consumers from the rest of Europe, this second point is not so important, since we can reach the destination in a few hours. In fact, with a suitable combination of 4 or 5 varieties (for example, Bacon, Fuerte, Hass, Lamb Hass and Reed) we can have Spanish avocado production throughout the year. And there are many other varieties that may be of interest.
Avocado varieties
Avocado productivity in new plantation: Making a good choice of varieties for production and for pollination is essential but not so simple, since there are pollinators that overlap very well in the flowering of the variety (Flower type A / Flower type B) in some areas of Spain, but not so. they do in others. Then, it is a theoretical concept in need of some explanation. Can you clarify something about it? And about the percentages and distribution of pollinators?
Avocado is characterized by a very low fruit set (around 0.15% in relation to the initial number of flowers produced). This low fruit setting is an adaptation of the avocado in terms of energy expenditure. Plants during evolution by natural selection have been developing strategies to have reproductive success. It is much cheaper for the plant to produce millions of flowers with pollen and a few fruits, since avocado fruits require a lot of energy for their development. Therefore, the low yield of avocado is something natural. Our research work indicates that most avocado flowers will not produce fruit even if they are pollinated. To this is added the fact that the avocado is native to America, where honey bees were taken away by the Europeans after the conquest; so, It is a species adapted to be pollinated by other types of insects and, however, commercially, pollination is carried out by honey bees.
Avocado productivity in new plantation: At IHSM La Mayora, we work on a line of research to diversify the pollinating species of avocado and increase the efficiency of pollination. On the other hand, it must be explained that avocado has a complex floral cycle: the flower first opens in the female state for a few hours, closes and the next day it reopens in the masculine state and, after a few hours, closes definitely. In type A varieties, the opening in the female state occurs in the morning and the opening in the male state in the afternoon of the next day. In type B varieties, opening in the female state occurs in the afternoon and in the male state the next day in the morning. However, there is generally an overlap between female closing and male opening flowers (which were female the day before) on the same inflorescence. If we have pollinating insect activity during this overlap, there may be pollination within the same inflorescence or between inflorescences of the same variety. The duration of this overlap varies according to environmental conditions and is greater in situations of high relative humidity and temperatures close to 20ºC. Therefore, in many situations most of the fruit set occurs during this overlap. However, planting type B varieties as Hass pollinators can be a safeguard, especially in years of low flower production. From the IHSM we believe that, in most areas of Spain, it would not be necessary to plant more than 5% pollinators and, in the case of not very large plots, they could only be planted as windbreaks in a narrow plantation frame. The duration of this overlap varies according to environmental conditions and is greater in situations of high relative humidity and temperatures close to 20ºC. Therefore, in many situations most of the fruit set occurs during this overlap. However, planting type B varieties as Hass pollinators can be a safeguard, especially in years of low flower production. From the IHSM we believe that, in most areas of Spain, it would not be necessary to plant more than 5% pollinators and, in the case of not very large plots, they could only be planted as windbreaks in a narrow plantation frame. The duration of this overlap varies according to environmental conditions and is greater in situations of high relative humidity and temperatures close to 20ºC. Therefore, in many situations most of the fruit set occurs during this overlap. However, planting type B varieties as Hass pollinators can be a safeguard, especially in years of low flower production. From the IHSM we believe that, in most areas of Spain, it would not be necessary to plant more than 5% pollinators and, in the case of not very large plots, they could only be planted as windbreaks to a narrow plantation frame. However, planting type B varieties as Hass pollinators can be a safeguard, especially in years of low flower production. From the IHSM we believe that, in most areas of Spain, it would not be necessary to plant more than 5% pollinators and, in the case of not very large plots, they could only be planted as windbreaks to a narrow plantation frame. However, planting type B varieties as Hass pollinators can be a safeguard, especially in years of low flower production. From the IHSM we believe that, in most areas of Spain, it would not be necessary to plant more than 5% pollinators and, in the case of not very large plots, they could only be planted as windbreaks to a narrow plantation frame.Avocado pollination
Well, we already know the demands of soil and climate, the importance of the variety / pattern and the pollinators, but before starting to plant, what should we take into account to establish the density and planting frame?
Avocado productivity in new plantation: The avocado is a vigorous tree. In some countries, vegetative growth is controlled by growth regulators, which, however, are not authorized for this crop in Spain. Therefore, in our conditions, the control of the size of the tree has to be carried out mainly by pruning. Therefore, commercially profitable proper management at very high planting densities is difficult. A 5 × 4 or 6 × 4 frame may be the best fit for most pattern / variety combinations.
Once the cultivation is established, the really complicated comes, especially during the first years of planting, starting from soil management to controlling pests and diseases, passing through irrigation, nutrition and pruning. What is the most recommended soil management for these first years? What alternatives do we have for weed control both in the planting row and in the center of the streets?
We have to start thinking of the weed flora as an ally rather than an enemy of the avocado plantation. The weed flora fulfills different tasks: it allows to improve the structure of the soil and reduce the evaporation of water and is useful for harboring different species of insects that can act as pollinators and as pest control. However, it is advisable during the first years of planting to eliminate this weed flora very close to the trunk to avoid competition with young seedlings. This can be done by using an anti-grass mesh or padding that prevents the growth of weed flora. After a few years, the very shading of the avocado leaves makes the weed flora near the trunk no longer a problem. In the middle of the streets,Soil management
Avocado productivity in new plantation: What type of training and / or sanitation pruning should we do and what time is the most appropriate to execute it?
The seedlings usually come already somewhat preformed from the nursery. We must form the trees from the beginning of the plantation, doing the pruning mainly in spring / summer. The pruning remains should be crushed and applied well at the base of the trees or in the streets. In recent years, there are some problems with aerial fungi that cause branch dieback. If we observe this damage in our trees, it is advisable to remove the affected branches and burn the remains instead of adding them to our plantations, since these fungi reproduce by aerial spores and it is convenient to reduce the inoculum pressure.
Regarding irrigation management, we know that avocado should not lack water, although it does not tolerate excesses either. What would be your recommendation in this regard? Regarding micro-sprinkler irrigation and drip irrigation, are there any advantages / disadvantages that make us choose one or the other?
Avocado is very sensitive to lack of water but, on the other hand, excess water can cause root suffocation and favor the development of soil fungi such as Phytophthora cinnamomi or Rosellinia necatrix. You have to be especially careful on heavy soils and, in that case, it may be advisable to use ridges to avoid problems, always bearing in mind that they have to be built allowing good drainage of excess rainwater. Both drip and micro-sprinkler irrigation can be used. Perhaps micro-spraying requires more attention from the farmer to review its proper operation. The important thing is that we do not lose water by percolation and that we bear in mind that the avocado has very shallow roots, so it is important that the wet area is as extensive as possible.Irrigation management avocado plantation
Avocado productivity in new plantation: Is avocado an easily mechanizable crop?
Soil management is easily machinable depending on the orography of the land. Although in any case, soil management through plant covers is a positive alternative for avocado cultivation. Pruning operations in a young plantation must be carried out manually, mechanization being impossible. The adult plantations could be partially mechanized, depending on the variety, but they should also be manually reviewed. The more erect varieties would tolerate a mechanical pruning better than the stocky varieties, mechanizing beyond this handling is not advisable.Finally, harvesting is an operation that must be carried out manually. Until now, there are no alternatives to be able to harvest the avocado mechanically.
Avocado productivity in new plantation: The oxygenation of the soil is something positive in adult plantations to improve the fruiting and ripening of the fruits, but does this practice provide any advantage in new plantations?
The avocado is very demanding in the oxygenation of its roots and appreciates everything that is aimed at promoting air circulation in the soil. In young plantations, it is important to favor the development of the root system and, therefore, soil preparation and crop management measures are essential to take care of the soil structure, avoid waterlogging and promote the presence of organic compounds that stimulate growth. root growth.
Regarding nutrition, starting from a soil analysis and a foliar analysis, what should the crop not miss and at what time?
In avocado it is important to take care of the supply of both macro and micro nutrients. Regarding macros, nitrogen should not be lacking throughout the tree’s growth period, which in our conditions takes place from late winter to early autumn. In addition, it has been shown that extra nitrogen applications throughout the fall positively index production, possibly improving flower quality in spring. Other macros to take into account are calcium, especially important in fruit setting and the first phase of development of the fruit, and potassium. Phosphorus is also basic, but from experiments carried out at the IHSM La Mayora, we know that in our conditions, there are usually no significant deficiencies even without contributions for years, although its foliar levels must be monitored.
Are the contributions of organic amendments recommended?
Organic amendments are highly recommended in avocado not only for the contribution of nutrients, but for their role in preserving the structure of the soil, increasing water retention or stimulating microbial life. In this regard, it is important to point out that some organic amendments favor the formation of suppressive soils against fungi that cause root rot in avocado.
Avocado productivity in new plantation: What would be the main pests and diseases to control in avocado seedlings? Do they represent a serious problem for this crop in our country?
In Spain we are lucky to be free of the main pests and diseases that affect avocados in other producing regions, which means that, with good management, we can produce organic avocados. The main pest of the crop is the crystalline mite, which appeared more than 15 years ago in Spain due to the introduction of foreign plant material and which has already established itself throughout the producing area. There are different species of natural enemies (mainly phytoseidae) that help in the biological control of the pest. We do not recommend applying acaricides or insecticides since their application eliminates the natural enemies of the crystalline mite and can also affect pollinating insects. In this way we can live with the plague that fundamentally has an aesthetic effect on the leaves, sincePests and diseases in avocado seedlingsIn terms of diseases, the most important are diseases caused by fungi. Aerial fungi of the family Botryospharea that cause branch dieback and soil fungi. In the case of Phytophthora cinammomi there are clonal tolerant rootstocks, such as Duke7, Toro Canyon or Dusa. In the case of Rosellinia necatrix, there is a selection program in Spain led by the IFAPA center of Churriana in Malaga, with the participation of the IHSM la Mayora and the IAS of Córdoba. Within that program there are already several advanced selections that we hope to be able to distribute commercially in the coming years. Also, in some circumstances, cases of sunblotch, a disease caused by a viroid, are found.
Avocado productivity in new plantation: Most important diseases in avocado
At this point and finally, where do you think the future of avocado in Spain is going?
Spanish production is less than 10% of European consumption and with the arrival of new players to the market (such as Colombia in recent years or Guatemala and other countries in the near future) that percentage will surely decrease. However, we have a clear opportunity to position ourselves in the most demanding segment of the European avocado consumer thanks to the fact that, unlike other origins, we produce a highly sustainable product with minimal or no use of phytosanitary products, a very efficient water management. irrigation, a low carbon footprint due to the shorter transport chain being close to our potential market and a much higher quality of fruit, since avocado that reaches the European market from other origins does so after several weeks of boat transport. Taking advantage of this opportunity is to clearly distinguish the Spanish avocado as a local product in the rest of Europe and diversify production, so that we can reach those potential consumers with a combination of varieties that allow us to produce avocado 12 months of the year compared to the current situation in which we only produce Hass for a few months (less and less months since there are practically Hass avocados from other origins throughout the year) and the rest of the year, the large Spanish marketers import Hass avocados from other origins for the re-export. Avocado productivity in new plantation: In my view, if we do not advance in the sense of differentiating ourselves by quality and proximity, it will be difficult for Spanish avocado to be competitive in the medium / long term in the European market.
