A group of more than 30 cherry growers and horticulturists from around the world took part in a recent tour in Argentina and Chile organized by Susan Pheasant, Mauricio Frias, and Claudia Acosta. Geraldine Warner compiled this report.
Orchardists in northern Argentina aim to be the first on the world market with Southern Hemisphere cherries, but Mother Nature doesn’t always cooperate.
Last year, nature was kind to cherry growers in northern Argentina, who had such a large crop they couldn’t harvest it all. This season, cool spring weather left them frustrated with a sparse crop that matured about a week later than usual.
Ideally, growers in the state of Mendoza would like to have cherries for sale in late October when the markets are empty. Being first to market is their number-one competitive advantage, one that brings a premium price of U.S.$2.00 to $3.00 a kilo ($1.00 to $1.50 per pound), but they face many adversities in realizing that goal. Mendoza, situated in the eastern foothills of the Andes mountain range, receives only 200 mm (8 inches) of rainfall a year. The latitude is 33S, the equivalent of southern California in the Northern Hemisphere.
Intense summer heat can burn the tree bark, while the mild winters leave the trees with inadequate chilling, necessitating use of Dormex (hydrogen cyanamide) as a rest-breaking treatment. Although water is plentiful, it can add salinity to the soil.
Fabio Tacchini and Ernesto Carbone, partners in a growing, packing, and export company called Amigo Fruits, have 19 hectares (47 acres) of cherries in the state of Mendoza. This season, they expected to harvest five tons per hectare (two tons per acre) on average, about half their usual yield.
In a block of Marvin cherries that they covered with a cloth to protect from sun and rain, the yield was a mere 1.5 tons per hectare, or less than a ton per acre. The trees bloomed profusely but did not set fruit.
“This is not a normal year,” said Carbone. “This is the worst year in history. Last year, we had very big production and this year no production. I think that the problem is very different growing conditions in the spring.”
The most dreaded of these conditions is the “zonda” wind that swoops down the eastern slope of the Andes. The strong, dry wind is warmed as it descends from the crest of the mountains, which are around 18,000 feet above sea level. The temperature can rise as high as 100F for the hour or two that the wind blows. Afterwards, it can drop into the 30s, Carbone reported.
Because of the hot, dry summers, the partners like to grow large, shady trees and don’t prune them until they are well established. Weeds are left in the orchard to help cool the environment.
Bing is a particularly poor producer in that location, and will be removed, the partners said. Santina, on the other hand, reliably yields four tons per acre. Other varieties that have been successful include Brooks, Stellar, Lapins, and the early variety Royal Dawn. Most of their trees are on Mahaleb rootstocks, with some on CAB 6P (Prunus cerasus).
Nearby, the family-owned growing, packing, and shipping company Guizzo Frutas Frescas has around 135 acres of cherries, along with peaches, nectarines, and table grapes. Fernando Guizzo said the company’s best business is growing and packing cherries for the early market. They have Brooks, Royal Dawn, Santina, Sweetheart, and Lapins cherries, but no Bing.
“We have seen over the years that in this area the production of Bing is very erratic,” Guizzo said. “It’s very difficult to grow it in this area.”
Guizzo has 10 hectares (25 acres) of cherries trained to a steep leader system (with ten branches per tree) and 10 acres on a central leader system (with 20 branches per tree). He uses scoring and Promalin (benzyladenine and gibberellic acid) to encourage branching. The limbs are tied down, and tree height is limited to about 3.5 meters (11.5 feet). He removes side branches to encourage more extension growth to fill the space. The central leader trees come into production earlier than the steep leaders, he has found.
Guizzo uses the strong CAB 6P rootstock because the idea is to have a vigorous tree as protection from the sun. He applies 60 to 80 kilos per acre of nitrogen through fertigation.
Raquel Zingaretti de Andia has a particularly productive cherry orchard at Tupungato that typically yields between 12 and 14 tons per hectare (five and six tons per acre) of cherries, and last year produced 17 tons.
The trees are on Mahaleb rootstocks because, in 1995, when the orchard was planted, CAP 6B (the preferred rootstock in the area) was not available, explained Estella Zaina, technical manager for the orchard. Varieties include Van Compact, New Star, and Stella, of which the latter is the most productive. The soil is a sandy loam, about 50 centimeters (20 inches) deep, and the orchard has rill irrigation. The Mendoza soils are naturally low in nitrogen, so nitrogen is applied at a rate of 58 kilos per ten tons of production.
Asked why she would rather use CAB 6P rootstocks when trees on Mahaleb have proven so productive, Zaina said some trees on Mahaleb have died because of irrigation problems. She finds CAB 6P easier to manage.
This year, flowers and fruit were lost because of low spring temperatures and the zonda wind. No thinning is done early in the season. About 20 to 25 days before harvest, the trees are pruned to eliminate part of the production, especially in productive varieties such as Stella.
Zaina said the five-hectare (12-acre) orchard was planted with the idea of minimizing labor. The trees were headed 50 to 60 centimeters (20 to 25 inches) above the ground and trained to a multiple leader system. This year was the first in the life of the orchard that branches were pruned back in order to stimulate more growth. The trees are topped mechanically every three years to maintain a height of 3.5 meters (11.5 feet).
Washington grower Andy Arnold of Ellensburg, who took part in the tour, said he was surprised by the adverse growing conditions that growers in northern Argentina face. “I was shocked at how arid it was,” he said.
But he thinks there is hope for some of the growers the tour visited, such as Andia, who was getting three times the yields of other growers. “Imagine if they ran some poly tube with microsprinklers. That would give them the capability to do frost control and really manage their water,” he said.
He felt that Argentine growers would benefit from a greater emphasis on pruning. “They have a concept of pruning, but I don’t think they believe in it, and that will adversely affect them,” he said. “You need to fill the space, and you need fruit bearing surface.”
Next issue: Chile