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  Food forever, for nothing

Imagine 12 floats riding on nutrient rich ponds. One is planted with rice saplings every week. On the 12th week the first is harvested and replanted. The cycle goes on without a break, amounting to four crops a year. No fertiliser is added and labour for ploughing and transplanting is eliminated. No irrigation either.

Fantasy? Well it has been done. Not only rice, even fruits and flowers have been grown on floats. All it requires is some subtle management of a fully integrated, zero-waste system pioneered by Dr George Chan, an environmental engineer. Chan was born in Mauritius, educated in England and served in the US. After retirement Chan spent 5 years in China from 1984. In that time he says he learnt as much from peasants there as from his university.

Chan’s starting point was the traditional, closely integrated agriculture practiced by Chinese farmers who raise crops, pigs, fish and fowl, in small spaces where the waste of one, feeds the next in a continuous chain. It is a system evolved through the centuries. And is not without disadvantages: recently it was suspected that the bird flu, escaped this knotty chain, to affect humans. Chan and Gunter Pauli, a man who champions ecology with enterpeneurial skill, have engineered some very crucial innovations into this ancient practice, and streamlined it, so that processes are scientific and continuous with no saturation occurring in any part.

Their Integrated Food and Waste Management System [IFWMS] milks bio-wastes dry and generates little atmospheric emission. Manure is rich in volatile nitrogen, which escapes into the atmosphere as nitrous oxide [N20], a notorious greenhouse gas. Instead, if manure is anaerobically digested, it yields biogas and the slurry is oxidised by bacteria into a more stable nitrite [NO2] and nitrate [NO3], which are usable by plants. Chan then leads the slurry into shallow basins to grow a green algae—chlorella— usable as protein rich fowl-feed.

At this point in the IFWMS, raw manure, once rich in organic matter, has been stripped substantially in two processes. In the digester, it yielded biogas and in the basins, chlorella. There is little in the basin residue that is unstable and seeking oxygen. So, when it is finally let into large ponds stocked with a colony of diverse fish, it does not go seeking scarce and valuable oxygen dissolved in water; instead it enhances prolific growth of different kinds of plankton, which are fish food.

When raw manure is dumped into the water as in traditional Chinese systems, it competes for oxygen, impedes the penetration of light and poisons the water. If the manure were composted, nutrient recovery is only partial. The fish pond in the IFWMS, on the other hand is a self-sustaining factory . Waste from fish in the upper colony is eaten by those is the lower, and finally a small residue descends to the bottom. This enriches the entire pond in a beneficial way. Convections or nominal agitation keep nutrients in circulation. When grain or plants are grown on the surface, they need neither fertiliser nor irrigation.

A more dynamic aquaponics is also possible, where nutrient rich water is led through narrow troughs. As they flow they give up nutrients to roots of plants suspended in the troughs. At the end of the run, whatever suspensions remain are cleaned up by plants like lemna, azolla and pistia.The water is now good enough to be recharged into the aquifer.

In another side-play, Chan mixes the sludge from the anaerobic digester with algae, macrophytes and crop residues and sterilises them by steam. The compound is then injected with spores for growing mushrooms. The process of growing mushrooms breaks down most of the compound into edible matter for livestock. What remains can be further used for culturing earthworms, and making vermi-compost.

Chan and Pauli believe eternally sustainable agriculture is possible with zero inputs. It might prompt the question: “All this forever, from nothing? Where does it all come from?” An accurate answer would be: “From the heavens via sunlight.”


References:  An article by Dr Mae-wan Ho, sent by reader C N Krishnaswamy. In George Chan’s own words. Similar principles of zero waste system applied in a brewery designed by Chan and Pauli.