The Dry Orchard Experiment
In Southern Portugal, water scarcity and desertification are becoming a reality. As climate change intensifies, prolonged droughts threaten our food security.
As part of the Orchard of Flavours agroecology project, we’re developing solutions to these environmental challenges while enriching the land with diverse flavours. By selecting trees that produce delicious, valuable crops and thrive on the region's natural rainfall, we aim to inspire landowners to reduce water use, combat desertification, enhance food security, and promote diverse income streams.
Our Goal
We are testing different drought tolerant fruit tree species in the Algarve, relying solely on the region’s average rainfall (around 500 liters per square meter annually) after an initial establishment phase of 1 to 2 summers.
Soil Preparation (March-April 2024)
To maximize water retention and soil fertility on our Dry Orchard Experiment, we:
Decompact the soil and remove stones
Add 20% organic matter
Create trenches for water retention
Plant nitrogen-fixing fava bean plants
Add different species of mycorrhizal fungi and organic fertilizer
Initial earthworks for preparing the experiment’s planting beds
Fava beans planted as green manure
Milan NEPALI incorporating fava bean plants as green manure into the beds
Applying a mycorrhizal fungi cocktail to the seedlings before planting
Irrigation
Our main focus is on keeping a short duration of the irrigation usage (1 to 2 summers). We use an efficient deep drip irrigation system that reduces evaporation and weed pressure, prevents disease, and minimizes erosion compared to traditional sprinklers.
In cases of extreme heat, we anticipate giving a maximum of 4 liters of water per plant, 4 to 5 times a week.
Planted Plots for the Experiment:
Northern plots:
1: Irrigation for the first summer only.
2: Irrigation for two summers.
Southern plots:
1: Irrigation for the first summer only.
2: Irrigation for two summers.
Western plots:
1: Irrigation for the first summer only.
2: Irrigation for two summers.
Selected Plant Species
All of the selected species are either drought tolerant or drought resistant. The annual rainfall in their native habitat either matches or is below that of the Algarve, and they provide edible and valuable produce:
Argania spinosa (Argan)
The argan tree produces nuts from which argan oil, a highly valued culinary and cosmetic oil, is extracted. The plant is extremely drought tolerant, adapted to the harsh conditions of the semi-desert Sous Valley of Southwestern Morocco, where it plays a critical role in preventing desertification.
Atriplex halimus (Saltbush)
This plant offers edible leaves that are salty and can be used in salads or as a cooked green. It is highly tolerant to drought and saline conditions, making it an important species for revegetation in arid and salty environments.
Cajanus cajan (Pigeon Pea)
Pigeon pea is a nitrogen fixer with edible seeds used in various culinary dishes around the world. It's drought resistant, thriving in tropical and subtropical regions where other crops may fail due to lack of water.
Capparis inermis (Caper)
Species of Capparis are known for their delicious edible buds (capers) and are adapted to grow in arid environments.
Chrysopogon zizanioides (Vetiver)
A perennial grass renowned for its robust root system, which can penetrate deep into the soil. This extensive vertical root network makes it highly effective in preventing soil erosion. It is used as the mulch generator for the planted plots.
Geoffroea decorticans (Chañar)
The Geoffroea tree produces edible fruits that are sweet, taste like toffee candy and are used in regional desserts and fermented drinks. Native to South America, this species is highly drought resistant. As a matter of fact, it can withstand not only drought, but also some frost and high temperatures.
Moringa oleifera and stenopetala (Drumstick Tree)
Moringas are known for their highly nutritious leaves, pods, and edible seeds. These fast-growing trees are very drought resistant, making them a valuable resource for nutrition in arid and semi-arid regions worldwide.
Morus alba 'Illinois Everbearing' (Mulberry)
This hybrid mulberry tree produces sweet, edible fruits similar to blackberries. It is drought tolerant once established and provides a reliable fruit crop even in less-than-ideal water conditions. It can also withstand some frost and high temperatures.
Prosopis alba (Mesquite, White Carob)
Known for its edible seeds and pods, this species is highly drought tolerant. The tree is a significant part of the diet in its native habitats (North Argentina and Chile), providing food in the form of mesquite flour made from ground pods.
Ziziphus jujuba (Jujube)
The jujube tree produces sweet, apple-like fruits that are edible fresh or dried. It is extremely drought tolerant, thriving in a wide range of environmental conditions, including arid areas. It can withstand some frost and high temperatures.
Ziziphus mauritiana (Indian Jujube)
Similar to Ziziphus jujuba, this tree bears sweet fruits that are consumed fresh, dried, or made into beverages. It is highly drought resistant, suited for cultivation in arid regions where other fruit trees might not survive.
Layout (planting date: April-May 2024)
Rows of vetiver grass were strategically placed at the bottom of the plots to prevent erosion and hold the slopes. After one growing year, the vetiver plants can be cut and used as mulch for the plot. Pigeon pea was placed at the northern edge of the plots where it acts as a ‘’green manure’’, fixing nitrogen into the soil. It can also be pruned and used as a mulch.
Planting layout diagram for the Dry Orchard Experiment
Observational Study
We will observe the performance of the trees under varying irrigation regimes during an initial establishment phase (1 summer vs. 2 summers).
Data monitored:
tree growth
yield
water usage
plant health
Results will be annually published on the Orchard of Flavours website.
Here, you can check the detailed table listing all the different species used in this Dry Orchard Experiment:
This article was compiled by Miguel COTTON, Dror AVITAL (plant biologist) & Anne BOUWMEESTER.
A big thank you to Anne BOUWMEESTER, who took an active part in this project as an intern (Masters in Tropical Forestry and Agroforestry, CZU Prague).
If you have any questions or suggestions, do not hesitate to contact us. miguel@orchardofflavours.com