127 lines
5.2 KiB
Plaintext
127 lines
5.2 KiB
Plaintext
more than who years and were the mam sautee- trl
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toedstull lor the inhabitants ol the entire valley,
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producing as many as seven drrleient ernps in a year,
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two ol which were maize tromptrrns, l' me,
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Mysletrrs a] the Mearean pyramids. lrlarper and Row)
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Properly maintained, chinampas eoutd remain lentle
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hir oentut-ies without having |u tie lallnw. Halts ol water
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vegetation were cut horn the surlaee or the eat-rats and
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towed to mounded banks where they were built up in
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layers and revered with neh mud scooped up horn the
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eanal bottom,
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l have extended the use oi the word ehinampa to
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inelnde any system in whreh a sequence ol canals and
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banks m approximate parallels are developed lor
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growing ltsh and marginal plants. Gwen a body ot
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standing water sueh as a lake or swamp. or a humid
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landscape with a elay base that will retain water all
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year, or a water table elose to the land eurlaee, it is
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possible to ereate a Mon Yummnw ol lond and
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water whoaeuaeaarebounded only by the limits set by
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climate. the imagination, and the harvest eapaerty ol the
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designer clunampa systems eombtne the best ot both
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worlds in soil and water eulture, and are m use in
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deliaie regions at Thailand to grow hsh and their twp,
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ducks and lrurt tress trim-re iml.
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There - one other strategte benetrt ol elnnarnpa
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systems, in that uselul but potentially rampant sped-s
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sueh as runner bamboo, vrne blaetrberry, hops, horse
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radish and litre erops an be water-isolated lrom other
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lan systems. Small moated islands have the same
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laei ry. and waterlowl can near or rest on these without
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tnterlerenee flout loses and leral eats
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We ean cheaply create ehrnampa swamps with a («W
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eompaeied retaining walls where water levels are
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regulated to but up over ehmampa systems. The raho
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nl channel in dryland eutture ts nnrrnally about n.3,
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but it we reverse this ratio, hubwomus nsh. plankton
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eatersand erayhsh are selletoragrng.
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Craylish and grass carp rn rhannels 2 m wtde,
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ranging overs swamp soap olseto m wide havea rieh
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lorage supply, plus land edges Tire lerreee or swamp
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can be drained. and in 3.4 weels harvested or erepped.
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and the vegetation ol tertaee and shell art as hsh lood
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and manure. with the nght seleetion ol speeies lduelss,
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mussels, weedeeating lrsh, rrayltsh, or eels) inch
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systems give yields in races ol mm lrg/ha 0! water
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turlaee. as many lood organisms and plants in:
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innmately available to the eanal ltsh.
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0n slopes, Huet (mm reports good ytelds ltom trout
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eanah in swttrrerland iled or unledl at 40-60% greater
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than broadepond eultute. For hill canals, a reliable
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water rnralre and elay soils are mml to permanenre
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The vegemhon ol the edges, shallows, and margins are
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a L'nklal latter in nutrient supply.
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4%
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13.8
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YIELDS OUTSIDE THE POND
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aow dporn
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We have dealt with 'm pond“ yields as laetors oi water
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quality and ltsh seleeiron. This does not take into
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amount upstream, rneorporaied, or downstream yields
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not dimly related to fish nesti rot nistanee. il we teed
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industrial ltsh [and pellets to duets or pigs, and let the
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mannies ol these animals lertllise the ponds, we get
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about the same yield tor even motel or such plenlrton
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and detritus teeders as prawns, carp, rrloprr. and mullet
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plus the duelr or pig produete. This is a eruesndn ot the
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eorteet routing ol the land supplied. and involves land
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yields
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Further, it we use letting: on land corp, teed that in
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pigs and ducks, and use their manures tor hsh, we get
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an even greater yield beyond that. we ran grow
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permanent luw-[emlm etop lor ptge ibanatu. pap-ya,
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atomst. use sparing lettiliser, ond get even greater total
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yields
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Alcuhul recovery and the subsequent brogas
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digestion oi green reed. tubers or starchy lood.
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manures, and wastes produees a 410qu shiny not one
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whit less lertile than the original substances. so that we
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are now arriving at an integrated tlriw—dnwn system ol
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tree lorage > animal protein a manures > aleohol )
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biogas a water etop tplantsl a loragehsh Even within
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this now, side eyelrs to worms, nntonrsttds, or Dairlrnrrr
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give better utilisation and a yield at every step The
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problem that we begin to stntre here it that no one
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lamily or person ean manage a very eomples integrated
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system We need a higheterder til soeral organisation in
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order manage these maxlmum yields lrtgure lust
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Mag us
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l-onds. depending on their shape. give a new and
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produettve edge in landseape. Trees and vines grow
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better there. and seleeted marginal plants drop leaves,
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insects, Insed wastes, lrutts. and exlend roots into
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ponds as ltsh loods They also shelter ponds or dlmcl
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wmds over them, prevent titer-heating and ehitlrng ol
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waters, and provide eover tor lorage species Thus, a
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whale set ol yields are available horn pond margins
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m
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We tnow that weedy shallows, brush piles, lenses,
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reetss or pipes, and ralts provide additional shelter,
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escapeinent. or lorage tn ponds, There ts a neh held
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here lot tnereasrrig yields. We eoirld dwmz 50% ol the
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pond to surh rover or lorage systems
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Downstream
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Water horn densely—stated ltsh ponds is a rish souiee
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ol irngahon water lot land plants Ytelds horn sewage
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or hsh-pond water are 2-5 times that lrom intalre water
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These land crops, as luels. tood, lorage, or struetsrral
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produet. must be integral to pond development il we
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are toreahse the lull value or fish ponds, and utilise the
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