Wicking beds

wicking worm bed - history 

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Wicking beds

History

I had been conducting research into ways of making more effective use of water when I was asked to visit Ethiopia to look for ways of growing sustenance food in times of drought.

I learned that the problem was not a simple lack of water but the variability of rainfall. If only took a few weeks break in the rainfall just at the critical times when the seed heads should be filling out to result in famine in the following season. Crops would be green but there was no growth, what they called a green drought.

A better way of storing water, even for a short period was needed. Limited water was available from springs but attempts to use this in furrow irrigation were not successful.

Soils in Ethiopia are poor, having been farmed for centuries, they lacked body, so water would soak in at the start of the furrow creating a bog and however long the water was applied it would never reach the end of the furrow.

I experimented by concentrating the flow by irrigating many small areas in sequence; - I called this micro flood - better but not a real solution.

I next tried burying a sheet of plastic film under the furrow so the water could not leak straight down.  Better - but the water moved sideways then leaked down.

 

I thought that if I formed the plastic sheet to make an underground  pond the plants would die from having their roots immersed in water,  

 But far from dying, they gave better, more productive crops than I had experienced.

Question - why use a furrow when water can be run underground using a slotted drainage pipe.  This would cut down evaporation and give a larger area for planting?

 

This worked well but why not combine several sections into one bigger section to form a larger underground pond.

The debate is that this would mean that plants would be growing directly above the underground pond.  Would the water form a stagnant pond  and become anaerobic?

Well it worked beautifully with no sign of anaerobic conditions.  It now looked very good so we started to install many wicking beds.

But now the problems started to appear.  Some beds were working really well with excellent production, much better than conventional methods but others were not so good.  Why? We could see that there were differences  in the types of soils we were using. 

We needed to conduct many experiments so instead of using in ground beds we set up multiple boxes.

 

The beds that were working really well had excellent soils, with a high organic content, largely well rotted compost.  The poorly performing beds had been filled with soil straight from the surrounding area-  a very poor heavy clay.

Adding fertiliser helped greatly with the established plants but we still had a problem with germination.  We tried using a layer of commercial potting mix on the surface, but germination was still poor.

Of course the surface with an underground pond system is dry so we experimented with a period of overhead watering to get the plants established.

But the results were not that good so we decided to peruse with underground watering even for germination.

 

There are benefits from watering from underneath, primarily the water is continuously flushed upwards so there is no stagnation. 

There is less soil compaction than with overhead watering and evaporation is reduced.  However with a poor soil there is insufficient wicking action.

We found that worm casting were far better than any other soil medium, giving excellent germination and growth.   This lead to the idea of making the bed into a worm bed.

We felt that many people would like to experiment with a wicking-worm bed.  Instruction on setting up wicking bed are on this website but if you have question you can email me

 

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