Hydroponic Sand Flow Bed
As an alternative for the destructive slash-and-burn method; a more intensive and sustainable production system.
OmniVerdi develops also alternative food and income generating production systems for rural areas, all targeting to decrease the pressure over ecosystems mainly by replacing the slash-and-burn method with intensive and sustainable production systems.
One of these systems is the hydroponic flow sand bed which reduces up to 90% the water needed to produce nearly everything; vegetables, pulses, grains, fruits, tubers, fibres, herbs, etc. Its does not depend on local soil, nor local climate, to produce year-round. It does not depend on local soil or climate, very easy and cheap to build and can be run even without electricity. If properly managed about 200m² of these beds can provide an average family with enough food and some income, year-round. Recommended is to plant these beds with a mixed crop permaculture, where each family can choose what and when they plant. Pest management will be needed because crops can be grown year-round.
It is a plant bed made with a strong plastic holding a layer of 25cm of sieved sand. A few times a week water with some nutrients from a reservoir is poured into the bed at one side, it then flows subterraneous to the other side, where it is drained out and flows back to the reservoir. When filled up the water level is at most 10cm but rises by capillarity to about 20cm high in the bed. As the top layer never gets wet there is almost no loss trough evaporation. Only what the plants uptake is ‘spent’. There is no leaching of nutrients, no salination risk, nor water seeping away into the soil, thereby very efficient in water use.
More even; when it rains the beds capture the rain water and it drains to the reservoir where it is stored and can be used for much longer time then when it would have fallen onto normal cropland. The reservoir can be used for fish production where the sand in the beds will serve as biofilter as it has an enormous surface for the formation of the nitrifying bacteria film.