Origin of Paddy Fields and Functions for Environmental Remediation in the Urbanized Areas of Yangtze River Delta - Environmental Contamination: Health Risks and Ecological Restoration - page 398

gram.of.soil.(grain/g.soil)..Archeologists.have.found.that.when.the.phyto-
lith.is.greater.than.5000.grain/g.soil.then.this.is.a.strong.indication.of.rice.
having.been.grown.there.in.the.past..The.results.obtained.in.our.studies.far.
exceeded. this. measure,. with. a. maximum. reading. reaching. more. than. 10 5 .
grain/g. soil. at. a. depth. between. 100. and. 200.cm. in. the. P-01. proile,. which.
indicates.the.long.history.of.rice.planting.within.the.area;.however,.the.same.
was. not. found. at. the. same. depth. for. P-02. proile.. According.to. 14 C.dating,.
the.proiles.of.the.buried.paddy.soil.portrayed.for.soil.organic.matter.(SOM).
and. fossil. rice. grain. had. a. calibrated. age. of. 3000. BP. (43-100.cm). and. 6280.
BP.(100-200.cm),.respectively,.which.placed.them.in.the.categories.of.ancient.
paddy.soil.and.prehistoric.paddy.soil,.respectively..These.indings.correlate.
with.the.results.of.archeological.interpretations.reported.from.potteries.fre-
quently.discovered.in.this.site,.for.example,.irrigation.pots,.jars,.and.so.on,.
from.the.Majiabang.culture..It.can.be.deduced.that.the.prehistoric.paddy.soil.
proile.(100-200.cm.in.P-01).had.already.developed.horizons,.as.A,.Ap,.B,.and.
C.contained.various.SOM,.certain.clay.distributions.and.soil.pH,.which.cor-
responded.to.other.properties.found.in.reports.regarding.buried.paddy.soils.
(Cao.2008,.Cao.et.al..2006,.2007,.2010,.Dong.et.al..2006,.Heike.et.al..2006,.Li.
et.al..2007,.Lu.et.al..2006,.2009)..Our.indings.provide.strong.support.showing.
that.China.may.be.one.of.the.birthplaces.for.irrigated.rice.cultivation.in.the.
world.and.the.buried.prehistoric.paddy.soil.found.at.the.Chuodun.site.is.the.
origin.of.paddy.soils.to.date.in.China.(Cao.2008,.Cao.et.al..2006,.2007).
EvidenceforRicePaddySoils'Sustainability
The.utilization.of.rice.paddy.soil.is.recognized.as.a.strategy.for.sustainable.
land. use,. which. also. has. ecological. functions. for. the. restoration. of. lood-
plain.biodiversity.(Cao.et.al..2004,.Greenland.1998,.Masaaki.2009,.Washitani.
2006);.however,.more.proof.is.needed.to.further.investigate.the.implications.
of.adopting.this.approach.
Rice Paddy Fields Located at the Loujiajiao Site Are
More Than 3000 Years Old
Approximately.1.2.hm 2 .of.“Box.Rice.Fields,”.surrounded.by.mulberry.gardens.
lying.in.the.highlands.(Figure.18.3),.were.found.at.the.Luojiajiao.site.(N36°65′.
E120°55′),.Zhejiang.Province..Large.quantities.of.more.than.a.tonne.of.ani-
mal.bones.(ca.. 14 C,.4710.BC).and.pottery.wares.(ca.. 14 C,.5210.BC).(Majiabang.
culture.period).were.collected.from.the.surface.layer.of.paddy.ields..Further.
to.this,.many.burnt.straw.ash.pits.(Figure.18.4),.fossil.rice.grains,.as.well.as.a.
grind.stone.for.polishing.tools.were.found.in.the.cultivation.layer.(0-25.cm).