Brazilian rhapsody in PET blue (J.C. Guimaraes)

Today, I received a very interesting comment from Brazil.  Thanks to Joao Carlos GUIMARAES we can now set up some experiments with PET bottles to limit irrigation.  Should this system work well, a lot of water can be saved.  Please read his suggestion to keep the rootball of young trees moistened :

Dear Sir

Since 2 months ago, I  have experimented to use 2 liters PET bottles to make irrigation of baby trees. Where we live, in Brazilian Amazonia, it is now summer season, meaning 6 months dry with high temperatures, until next December.         

It is very simple:

* Just perforate a little hole –  2 mm – at bottom of the bottle.

* Excavate a hole in the soil with the diameter of the bottle,  more or less 20 cm deep, near the roots.

* Put bottle in the hole. Cover side with soil.

* Fill bottle with water before putting it in the hole.

* Close well the  bottle cap. (If you keep bottle open or badly closed, water will infiltrate quickly in the soil).

* When soil is dry, it pulls water from the bottle (via capilarity,  or percolation, or vacuum,  I don’t know  very well).

* When soil is humid, the level of water in the bottle stays almost intact.

* Depending on soil and sun, I  completed the water level once to 3 times a week.

It’s interesting to see that some bottles get deformated, crushed,  because of the vacuum force of soil suction.

Now I’m going to set up an experiment with 2 or 4 bottles per tree. Then, I don’t need to wait for the rain season to plant more trees.

As I said before, this is a new experiment. Maybe others could share it and upgrade it.  If you want some photos of it, I will be glad to send them to you.

Best regards

João Carlos Guimaraes
Paragominas
State of Pará
Brasil

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Isn’t this a marvelous idea ?  I know that, when planting trees in urban areas, perforated tubes are put in the plant pit close to the stem to facilitate watering.  But this quite simple technique to use PET bottles was unknown to me.  Should you know more about it from literature,could you please send me a comment ?

I intend to set up some experiments with this “system for water use efficiency” for our UNICEF project in the Sahara desert.

Looking forward for your reactions.

Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

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