High-Density Plantings—A New Look at Pecans in Argentina
However, the Argentine Northwest (Noroeste Argentino, or NOA for short in Spanish) has a different productive culture, where the high-density model is widely used in fruit trees in general. For example, lemon and avocado farms began with low-density planting systems and started intensifying and migrating towards productive projects of higher densities. In pecan, this intensification has been implemented for over a decade, with plantation frames of 7 by 10 meters (23 by 32 feet), 6 by 9 meters (20 by 30 feet), and up to 6 by 8 meters (20 by 26 feet), corresponding to densities of 142, 185, and 208 trees per hectare. So, talking about medium and high density means planting between 140 to 250 trees per hectare, compared to the traditional spacing of 100 trees per hectare.
Agronomists Enrique Orell and Mariano Marcó and growers Paola Graña, Sebastián Valdéz, Ernesto Ríos, and Josefina Manfrin share their experience with this system, as well as some surprising results.
“It is a cultural and business issue. We are looking for the project to enter production as soon as possible and for the investment to be repaid as quickly as possible,” Orell begins. He questions the pecan tree’s longevity, one characteristic that attracts growers the most to plant pecan. Orell and the producers in the Argentine Northwest ask themselves, “100 years for what?”
“Markets change and cultivars change. A 20 to 30-year-old fruit tree should be considered for replacement since we always need to achieve higher productivity and production with whatever approach we seek, both in conventional and organic management,” Orell explains.
Production in medium and high-density systems has characteristics such as greater precocity in entering production, greater efficiency in soil and water use since trees are smaller, higher production per unit of surface, and less need for pruning at the beginning of the plantation. But it also means a larger initial investment and the need for proper technical management of the crop, following the instructions to the letter from the beginning. “Just as the number of plants increases, knowledge and monitoring must be increased to achieve the desired objectives. There is no worse business than planting a high-density orchard and managing it as if it were a low-density one,” says Agronomist Mariano Marcó.
This system’s technical foundations can be summarized in the following points.
- Early Production: A high-density orchard aims to have more compact trees with enough foliage to develop into flowers from the second season to start producing in the third season. And a structure always in a modified central axis.
- Productivity: Given the previous point, the trees produce more yield per tree earlier, which translates into more kilos per hectare in years 4 and 5 that are not common in a traditional low-density system. The orchard in these years covers its expenses with the yield harvested from the sixth year onwards; the farmer begins to recover their investment.
- Intensification, monitoring, and management refer to the need for a trained and innovative technical team with periodic visits to the orchards.
- Use of space: High density implies more plants and less unproductive space in the orchard for fewer years.
- Operational tasks’ cost is at first 30 to 40% greater than in conventional systems when the trees are juvenile, but it then equals conventional costs at the same production level, resulting in lower cost per plant and, more importantly, lower cost per kilogram (or pound) of produced nut.
- Finally, the high-density system implies higher initial investment because it requires more investment in plants, a little more in irrigation infrastructure, and more in management and monitoring. But, as mentioned before, that higher initial investment pays for itself in the short term due to the higher productivity of the early years.
In Argentina, most high-density orchards are located in Salta, Tucumán, and Chaco. These areas have specific agroecological differences from those found in the Northeastern Region, where Entre Ríos, Santa Fe, and Buenos Aires provinces are. In the latter, conditions are more similar to those in Georgia or the southeastern United States; the region has the largest planted area. “I believe that higher densities would be a total success in the Northeast Region. It has more to do with the advisor having knowledge and the management of the system than with the area’s possibilities. It’s a paradigm shift from retirement or grandchildren’s cultivation to high profitability in the short term,” says Orell.
Josefina Manfrin is a pecan grower with 35 planted hectares (86 acres) in the town of Metán in Salta province. Her company, El Mangrullo S.A., has one of the oldest orchards in the Argentine Northwest. Although she started the project 16 years ago, the orchard already has a row of 40-year-old pecan trees that a previous owner had planted. When Manfrin moved with her family to live on the property, she wondered what to do with those existing trees and decided to produce pecans. With little knowledge of the crop and little advice, she planted 1 hectare with mixed varieties in 2006 and another hectare in 2007. Both with a planting frame of 10 by 10 meters (about 32 by 32 feet), which was the most common back then.
Up until 2011, Manfrin didn’t know how to manage the orchard, and it was thanks to the visit of a group of local growers and Agronomist Conrado Rodríguez Lara from Mexico that she understood how to manage pecans. That year the group “NOA Pecan” was formed with 10 growers determined to bet on pecans in Salta and Tucumán provinces, accompanied by an advisor, who at that time also had no knowledge of the crop. This allowed for the exchange of ideas, research, and extrapolating cases from other areas and even similar crops, and mainly to share and learn from successes and mistakes so that pecan could grow, develop and progress in the region. The group continues to this day—12 years later.
Thanks to this group’s formation and the support network to move forward, Josefina decided to plant another 5 hectares in 2011. With more advice and knowledge, she opted for a more intensive planting scheme of 7 by 10 meters (23 by 33 feet). At that time, the nursery from which she purchased the plants recommended the ‘Choctaw,’ ‘Shoshoni,’ and ‘Pawnee’ varieties.
She planted more trees in 2013, 2015, and 2016, completing 35 hectares, maintaining the same spacing, and betting on varieties like ‘Kiowa,’ ‘Pawnee,’ ‘Desirable,’ ‘Sumner,’ and ‘Oconee.’
“At that time, I read a lot of the technical data sheets from the University of Georgia for each variety, and it was the only way to decide which variety to plant,” she says. “We didn’t even know what the fruit of each variety we were evaluating looked like, only from pictures.”
When Manfrin started, she had 23 varieties in her orchard. As she harvested and saw how complicated it was to have mixed varieties, she began to replace the less productive ones. “We did many different tests [with topworking], and today we have a system that makes it easier for us, but it becomes complicated with very large plants,” Manfrin explains. “That’s how we reduced to 16 varieties. A great learning was to understand that it’s important to be able to make blocks of a few varieties because otherwise, the harvest becomes very complicated. In lots where we still have plants of different varieties, we harvest very carefully, and the process is very slow.”
The results obtained so far are surprising. The ‘Mahan’ variety has achieved 3 tons per hectare for three years in its 13th, 14th, and 15th years. On the other hand, the ‘Shoshoni’ variety has been producing high yields for four years now: 3 tons (year 8), 4.5 tons (years 9 and 10), and last year, 5 tons (year 11) per hectare. “I’m talking about these varieties since they’re among the first ones we planted, and we have more years of experience managing them and knowing their productive capacity, but there are many other varieties we’re betting on today, but we need several years to start understanding and recognizing how they perform and what characteristics they have,” Manfrin says.
The key is constant work and giving the plant everything it needs from day zero while creating and adjusting a management plan week-by-week through observation. This allows producers to start harvesting some nuts in the third or fourth year.
“I’m not sure if I would plant ‘Mahan’ again, but ‘Shoshoni,’ if I evaluate its precocity and productivity, is a plant that has high productive potential in its early years. Although [research suggests] that from year 30 onwards, it begins to have a lot of alternation and loss of quality, a fact that I cannot affirm now,” Manfrin says. “There is still a long way to go to fully understand the potential of each variety. Today, varieties such as ‘Kiowa,’ ‘Pawnee,’ ‘Oconee,’ and ‘Sumner’ are being proposed, among others, and also ‘Western’ and ‘Wichita,’ the latter two for drier areas of the country like mine. I believe that little by little we will gain our own experience, as we still have many years to understand how each variety behaves in our country.”
It is expected that trees planted in high-density will reach their productive potential between years 10 and 12. In the Argentine Northwest, there are some orchards in year 14 whose level of productivity has not declined. It will be a matter of time to see how long it will last this way.
The question then is whether this early production is compensated later. That is if the plant will maintain that level of productivity for the same number of years as in a conventional system, where it enters production later. According to Orell, the two systems are not yet comparable.
“Conventional systems have shown that, due to the management system adopted in Argentina 20 or 30 years ago, they have shading problems since they are very large trees, with equivalent structures, which entail a high maintenance cost,” Orell explains. “As these problems have had to be solved with recurrent pruning, we believe that the productive potential of the low-density system has not yet been reached. We still have to wait a bit longer to compare both systems; however, we believe that due to the structure of the plant that we achieve in high-density systems, it should be more efficient in the use of resources and translate into higher productivity per unit of surface area.”
In Trancas, a town in the north of Tucumán, project administrator Paola Graña and her husband, agricultural engineer Sebastián Valdéz, teamed up with Ernesto Ríos in 2016 to plant a 25-hectare orchard in an ultra-high-density model. Called Don Fermín, the orchard has 208 trees per hectare on an 8-by-6-meter spacing. Ríos owns the property, which previously had an unsuccessful ‘Chandler’ almond orchard.
The team behind Don Fermín chose varieties based on availability and planted in four stages from 2016 to 2019 with ‘Wichita,’ ‘Western,’ ‘Stuart,’ ‘Pawnee,’ ‘Nacono,’ ‘Oconee,’ and ‘Shoshoni.’ Of the 5,200 trees, 5,000 were container trees, and only 200 were bareroot. It is worth mentioning that container trees are widely used in the Argentine Northwest, unlike northeastern Argentina, which uses mainly bareroot.
The project’s goal was clear from the outset: to reduce the unproductive period of the farm through the use of high-density cultivation techniques for other fruits that were successfully tested, such as walnut, avocado, and lemon, and to generate knowledge and strengthen relationships to capitalize on with similar projects. The partners established 30 years as the project’s time frame. The project’s objectives were to start covering costs as soon as possible—achieved within years 6 through 7—recover the investment between years 10 and 12, and give the partners a horizon of profits that could be achieved in 25 years.
When asked what they will do after year 30, Valdéz says he does not know, but when a plot becomes unproductive, it will be changed or renewed. “The project works as long as it generates what we set out to generate,” he says. “When it no longer generates the expected return, it must be changed.”
In this sense, both Valdéz and Graña emphasize that high density is not just a different spacing but a different mentality and dedication. “Don’t interpret that going from 100 to 200 plants per hectare is the magic formula to get more pounds in pecans because if you do it with the same mentality as low density, you will lose money,” highlights Graña.
One aspect they highlight regarding the tree’s potential is pruning, as Enrique Orell explains. “When you remove structure from the tree, you are reducing yield. Every time a branch is removed, yield is forfeited. So what we are doing is a very meticulous pruning job, and that is what ends up achieving precocity,” says Valdéz.
“We believe that with the management we are doing in the orchard, the yield will increase until a certain year and then stabilize. Although we understand that it will be alternating in the case of pecans, we hope this alternation has a smaller impact,” explains Graña.
So far, it seems to be working. The number of pounds per tree achieved with that concept of “just right” pruning—reaching the right structure and then letting the plant balance itself—is impressive.
“Our challenge now, starting from year 7, will be how to intelligently achieve a balance between pruning and structure, and on top of that, combining pruning with on and off years. There is no magic recipe, but it has to do with making sure that from minute 0 to the fifth year, the orchard lacks nothing. High density equals high-intensity work and dedication,” says Valdéz. Undoubtedly, this high-density planting is a change in mentality for the pecan business in Argentina. The new projects in the northern part of the country are entrepreneurial, on a large scale, and built as a business unit within the company. It remains to be seen if the rest of the producing regions will decide to transform and join this approach to pecan cultivation. According to Valdéz, “This [technique] will professionalize the sector, and we believe it will make us competitive as a supplier to the world. The concept we want to convey is that our difference in the market will be that we are efficient in cost per kilo. We have always been characterized in the Argentine agricultural sector as being productive and efficient, and pecan will not be an exception to that.”