May 10, 2023 Grace Diaz

A hydrated and humid soil can save up to 25% of water in walnut plantations

The walnut tree is a deciduous tree that can reach up to 25 meters in height with a trunk that can exceed 2 meters in diameter. This type of tree produces the highly desired walnut. And every year, exports increase in Chile, and for this new season, the data is positive: according to a report from the United States Department of Agriculture (USDA) for the 2022/23 campaign, Chile will have an estimated production of 165,000 tons of walnuts, an increase of 7.8% compared to the 2021/22 campaign, following an increase in planted area and higher accumulated yields.

Chile aims to reach 200,000 tons by 2024, and the Asian giant is the great challenge due to its increasing walnut production, with a 25% increase in 2022, reaching 1.4 million tons.

As stated at the past ExpoNut 2022, José Luis López, director of ChileNut and Export Manager Nuts & Dried Fruit at the company Greenvic, emphasized the importance of how Chile will differentiate itself in order to place its national fruit in the market, as China will have greater ease in moving its volume to Eastern Europe and the Middle East, with larger volumes and lower prices. Therefore, it is urgently necessary to strengthen markets such as the Middle East and to take advantage of markets where Chilean walnuts differentiate themselves in terms of quality, including Europe and India.

Chilean Walnut, Soil, and Water

Regarding walnut production in Chile and the promising numbers, the drought is relentless in the central zone, and the limited availability of water in these regions has made it necessary to incorporate new irrigation tools for better hydration and soil moistening.

During the webinar organized by ChileNut and AQUA4D, progress was presented in the application of their irrigation technology in walnut plantations, achieving efficient hydration and moistening of the soil and active management of accumulated salts and minerals to ensure good moisture distribution in the active root zone.

International expert, Enrique Rebaza, gave a presentation on how this technology has improved the irrigation and humidification standards, as well as how it has improved soil quality through the displacement of salts. “One of the main problems we have worked on in walnut plantations is the difficulty of displacing salts even with heavy irrigation, and this is due to the high salinity of the soil. Effective moisture in the tree band or line is key to managing accumulated salts in the soil, whether on the surface, below the active root zone, or between emitters or hoses; chlorine and sodium become an impassable layer, preventing irrigation from penetrating or, in other cases, causing it to resurface and poison the walnut trees. Thus, heavy irrigation is ineffective,” he says. “By applying AQUA4D through the same irrigation system, salts were effectively displaced in the different cases worked on in the same campaign after between 30 and 60 days of management,” the specialist added.

Enrique Rebaza

“The new water dynamics established in walnut plantations by AQUA4D has restored the soil pores that roots can now explore without the stress of accumulated salts, displacing salts to deeper horizons or to the streets (vertical and horizontal movement). “In this way, the soil becomes unclogged,” Rebaza says.

Through scheduled monitoring and information processing on water and soil quality, they sought efficiency in salt management, including field mapping. “We always seek the optimum irrigation for soils, contrast it with foliar monitoring, and seek efficiency in salt management. We wanted to achieve a less stressed plant, taking in water, growing, and producing fruit,” he adds.

“We also had to work on a case where accumulated sodium in the soil needed to be moved, and in the same campaign, after 70 days of working with the walnut trees, we were able to reorganize irrigation and displace the sodium so that the tree could be properly hydrated. When salt accumulates, the soil is sealed, the minerals do not hydrate, and “coarse” crystals are generated, and even with abundant irrigation, the soil is not hydrated, and therefore the walnut tree is not hydrated,” Rebaza explains.

Through soil pits and probes, moisture levels are monitored from 10 to 120 centimeters deep, and the result obtained is that moisture is maintained above 50% at all levels excavated, even up to 120 centimeters, achieving good hydration. “In 30 days, we achieved ideal soil hydration for walnut trees, with a good balance between the frequency and volume of irrigation with AQUA4D®,” comments Rebaza. “In general, the water consumption savings achieved in this type of treatment is 25%,” he says.

The largest surface area of walnut trees planted is found in the central-southern regions of the country, between Valparaiso and Maule. The main producing zone is the Metropolitan region, which represents 37.6% of the planted area, while the total surface area has grown by 16.4% in the last three years.

Source: Un suelo hidratado y humectado puede ahorrar hasta 25% agua en plantaciones de nogales –