more than who years and were the mam sautee- trl
toedstull lor the inhabitants ol the entire valley,
producing as many as seven drrleient ernps in a year,
two ol which were maize tromptrrns, l' me,
Mysletrrs a] the Mearean pyramids. lrlarper and Row)
Properly maintained, chinampas eoutd remain lentle
hir oentut-ies without having |u tie lallnw. Halts ol water
vegetation were cut horn the surlaee or the eat-rats and
towed to mounded banks where they were built up in

layers and revered with neh mud scooped up horn the
eanal bottom,

l have extended the use oi the word ehinampa to
inelnde any system in whreh a sequence ol canals and
banks m approximate parallels are developed lor
growing ltsh and marginal plants. Gwen a body ot
standing water sueh as a lake or swamp. or a humid
landscape with a elay base that will retain water all
year, or a water table elose to the land eurlaee, it is
possible to ereate a Mon Yummnw ol lond and
water whoaeuaeaarebounded only by the limits set by
climate. the imagination, and the harvest eapaerty ol the
designer clunampa systems eombtne the best ot both
worlds in soil and water eulture, and are m use in
deliaie regions at Thailand to grow hsh and their twp,
ducks and lrurt tress trim-re iml.

There - one other strategte benetrt ol elnnarnpa
systems, in that uselul but potentially rampant sped-s
sueh as runner bamboo, vrne blaetrberry, hops, horse
radish and litre erops an be water-isolated lrom other
lan systems. Small moated islands have the same
laei ry. and waterlowl can near or rest on these without
tnterlerenee flout loses and leral eats

We ean cheaply create ehrnampa swamps with a («W
eompaeied retaining walls where water levels are
regulated to but up over ehmampa systems. The raho
nl channel in dryland eutture ts nnrrnally about n.3,
but it we reverse this ratio, hubwomus nsh. plankton
eatersand erayhsh are selletoragrng.

Craylish and grass carp rn rhannels 2 m wtde,
ranging overs swamp soap olseto m wide havea rieh
lorage supply, plus land edges Tire lerreee or swamp
can be drained. and in 3.4 weels harvested or erepped.
and the vegetation ol tertaee and shell art as hsh lood
and manure. with the nght seleetion ol speeies lduelss,
mussels, weedeeating lrsh, rrayltsh, or eels) inch
systems give yields in races ol mm lrg/ha 0! water
turlaee. as many lood organisms and plants in:
innmately available to the eanal ltsh.

0n slopes, Huet (mm reports good ytelds ltom trout
eanah in swttrrerland iled or unledl at 40-60% greater
than broadepond eultute. For hill canals, a reliable
water rnralre and elay soils are mml to permanenre
The vegemhon ol the edges, shallows, and margins are
a L'nklal latter in nutrient supply.

4%

13.8
YIELDS OUTSIDE THE POND
aow dporn

We have dealt with 'm pond“ yields as laetors oi water
quality and ltsh seleeiron. This does not take into
amount upstream, rneorporaied, or downstream yields
not dimly related to fish nesti rot nistanee. il we teed
industrial ltsh [and pellets to duets or pigs, and let the
mannies ol these animals lertllise the ponds, we get
about the same yield tor even motel or such plenlrton
and detritus teeders as prawns, carp, rrloprr. and mullet
plus the duelr or pig produete. This is a eruesndn ot the
eorteet routing ol the land supplied. and involves land
yields

Further, it we use letting: on land corp, teed that in
pigs and ducks, and use their manures tor hsh, we get
an even greater yield beyond that. we ran grow
permanent luw-[emlm etop lor ptge ibanatu. pap-ya,
atomst. use sparing lettiliser, ond get even greater total
yields

Alcuhul recovery and the subsequent brogas
digestion oi green reed. tubers or starchy lood.
manures, and wastes produees a 410qu shiny not one
whit less lertile than the original substances. so that we
are now arriving at an integrated tlriw—dnwn system ol
tree lorage > animal protein a manures > aleohol )
biogas a water etop tplantsl a loragehsh Even within
this now, side eyelrs to worms, nntonrsttds, or Dairlrnrrr
give better utilisation and a yield at every step The
problem that we begin to stntre here it that no one
lamily or person ean manage a very eomples integrated
system We need a higheterder til soeral organisation in
order manage these maxlmum yields lrtgure lust

Mag us
l-onds. depending on their shape. give a new and
produettve edge in landseape. Trees and vines grow
better there. and seleeted marginal plants drop leaves,
insects, Insed wastes, lrutts. and exlend roots into
ponds as ltsh loods They also shelter ponds or dlmcl
wmds over them, prevent titer-heating and ehitlrng ol
waters, and provide eover tor lorage species Thus, a
whale set ol yields are available horn pond margins

m

We tnow that weedy shallows, brush piles, lenses,
reetss or pipes, and ralts provide additional shelter,
escapeinent. or lorage tn ponds, There ts a neh held
here lot tnereasrrig yields. We eoirld dwmz 50% ol the
pond to surh rover or lorage systems

Downstream
Water horn densely—stated ltsh ponds is a rish souiee
ol irngahon water lot land plants Ytelds horn sewage
or hsh-pond water are 2-5 times that lrom intalre water
These land crops, as luels. tood, lorage, or struetsrral
produet. must be integral to pond development il we
are toreahse the lull value or fish ponds, and utilise the