SLECI = Self-regulating, Low Energy, Clay based Irrigation

The SLECI system, developed by one of the DIVAGRI partners, the German Research Institute IPT

The principle of the technology.

Schematic representation of how the water is released from the moistened clay bodies into the surrounding earth

All these three pictures are taken from the SLECI | DIY and O&M manual. For more information please check: 

https://www.youtube.com/watch?v=WL3hp_GOt98&ab_channel=LeanneSeeliger

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We started to adapt the SLECI irrigation system to our new cashew field.

Field size 2,500 sqm

Goals

  • Establishment of a cashew plantation under irrigation conditions.
  • Test of an underground irrigation system (SLECI) in different installation methods compared to drip irrigation
  • Demonstration of the technique to smallholders in Mfantseman, possibly beyond
  • Accompanying economic perspective over 5 years in national and international terms

Test duration: 3 dry seasons, 3 rainy seasons

Natural conditions: The test field area is located on a previously unused area with secondary forest (bush growth) The area is flat. It is located on a hill about 100m above sea level and is about 400m from a lake.

Soil quality: loamy sand in a hardened structure, containing rocks.

Preconditions: A water pipe to the hill near the test field has already been laid.

rainfall amounts: rainfall is almost exclusively in the period from April to November in two rainy seasons.

It was hard work with the bush knife, the saw spade and the pickaxe to clear the SLECI area of ​​vegetation. Afterwards we worked with the tractor with harrow and plow and finally we leveled the new field

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Dr. Maik Springmann explains the principle of the SLECI technology.

SLECI = Self-regulating, Low Energy, Clay based Irrigation

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Hard work for the tractor to prepare the field for the new cashew plantage as a demonstration field for the innovative SLECI irrigation

April 2024: We bought good quality seedlings of cashew trees from a nursery and started to plant them with a distance of 6-7m.
We put a mix of cow dung and compost earth and local soil into the planting hole around the seedling and watered the seedling abundantly.
 
We used 25cm long bamboo pipe segments and put them aside of the roots into the earth for easy watering by hand in the future. We covered the planting hole with weeds to keep the soil humid.
It´s a perfect time for planting them now, in the beginning of the rain season.
Unfortunately the planned SLECI system didn´t arrived in time, so that we had to install the technology now inside our greenhouse.

Within our 5 worshops from 29.11.- 4.12.2024 we presented as well the innovative SLECI system to our farmers.
As we already mentioned we installed the SLECI system now in our greenhouse.
The advantage is here, that we can generate weather and season independant measuring data and we can easily compare the advantage of SLECI with the common drip irrigation.
 
Due to the peculiarity that the irrigation system is invisible after its one-time implementation (it is a subsurface watering system) we left some trenches open to show the effect of the moist clay bodies which supply the plants with water.
We also pointed out the points to consider of the system, for example, that the supply lines have to have a minimum depth of 30 cm. Otherwise the risk to destroy them while ploughing is big!

open trenches show the SLECI system

the clay bodies have to be covered/surrounded by sand

at the right side: SLECI plus drip
at the left side: only drip irrigation

a proper functioning SLECI clay body

a destroyed clay body due to mechanical tillage and insufficient laying depth

Maik Springmann is trying to explain the interaction between plants and soil and the needs of them to the small scale farmers. He used simple, basic linguistic images to arise another way of understanding for these botanical connections.