Layering Plant Species in Syntropic Systems: Enhancing Productivity and Sustainability
In my previous articles, we focused on the benefits of syntropic farming in water management, leading to generating farmlands on the tropical island of Curaçao. As we demonstrated, after 6 months, we were able to lower the irrigation rate from 4-liter water per square meter daily to the same amount every 3 weeks. I also explained how the rows of Mombasa grass act as a natural irrigation system.
Today, I want to present another interesting result of planting water in the semi-arid climate of Curaçao.
We had a deep well on the land. Initially, we could only pump water for about 20 to 30 minutes a day. After that, the well ran dry, and we had to wait another day before it was possible to use it again. The Ministry of Agriculture provided us with water carried in big trucks every week to cover our water needs.
After a year, we could use the pump as long as we wanted without reaching its limit. The groundwater level was rising again. This is a unique situation on an island where the groundwater layers are getting deeper and deeper. Many farms on the island cannot use those wells anymore because of the infiltration of seawater (salinization problems). Syntropic agroforestry provides a long-term solution for a phenomenon that endangers the existence of agriculture on our island.
Now let us focus on the second planting water feature next to the diminishing of evaporation thanks to the phenomenon of condensation due to planting Mombasa grass.
The next important feature of planting water is stratification. Stratification can be translated as creating canopy layers. The function of stratification is to maximize photosynthesis for all plant species of the system.
Photosynthesis is the process in which plants transform the heat of both carbon dioxide and sunlight into energy and coolness. And it's exactly this coolness we want to achieve with maximization of photosynthesis: the more plants, the more photosynthesis, the more coolness, the more condensation of water vapor.
"Layering" the plant species for maximum efficiency
To use photosynthesis most efficiently, we plant trees and vegetables according to sunlight demand. Some plants need a full spectrum of sunlight. We call those species emergent species. They have an emergent need for sunlight.
Other species have a high demand for sunlight. They can tolerate just a bit of shade, but generally, they need at least 60 to 80% of sunlight to thrive and be provided (see illustration).
The next layer is species with a medium demand for sunlight (about 40%).
Finally, we have the low strata of species that love to grow in the shade and just need 20% of sunlight.
So, we can plant very dense layers of trees next to each other as long as they belong to different strata (layers/heights). We need to create a layout that maximizes the exploitation of sunlight; every species can receive an optimum amount of sun, nothing less nor nothing more. This will prevent many diseases and pest outbreaks and accelerate growth and production. A well-known example is coffee. It is typically a shade-loving crop that cannot tolerate full sunlight. Plant coffee as a mono-crop will not only cause a loss of sunlight that can be transformed into energy or harvests. It also causes a lot of diseases and pests.
An example of an optimum syntropic system
Now, let us observe the illustration. On the left hand, you see the amount of sunlight the different strata need and also how much space they can obtain on the farm. The rule is here: the lower the demand for sunlight, the more space they can occupy. Shade-loving trees like cocoa and coffee can occupy 80% of a treeline.
Mediumstrata oranges with a demand for sunlight can occupy 60% of the treeline.
High-strata breadfruit with a demand for sunlight of at least 60% can occupy 40% of a treeline.
Finally, the emergent coconut can occupy 20% of a treeline.
On the right hand, we witness the secret of planting water: the emergent are good for only 20% of photosynthesis, so the cooling effect is only 20%. The lower we get, the more photosynthesis, the lower the temperatures are getting. We should take into account that water vapor moves from hot to cool. It is easy to understand how we reversed the normal flow of water ωαπορ from the soil to the atmosphere. Instead, we created a downward-pulling effect of water vapor. The number of cool leaves due to photosynthesis increases condensation the lower we go. All that condensed water vapor will drip downwards into the soil, which has become the coolest place.
Further reading
What is Syntropic Farming, and how can farmers benefit
Water Conservation Measures: The Role of Mombasa Grass in a Syntropic System
The Impact of Syntropic Agroforestry on Water Usage and Farm Resilience
