Environmental Engineering Reference
In-Depth Information
Introduction
Rice. is. one. of. the.staple.foods. for. more.than.3. billion. of. the.world's.pop-
ulation,. particularly. among. the. Asian. communities. (Darr. 2010,. De. data.
1981,.Li.1992,.Loftas.1995)..Therefore,.it.is.important.to.improve.the.fertil-
ity.of.soils,.the.supply.of.water,.and.the.management.of.diseases.in.order.
to.maintain.successful.rice.cultivation,.thus.ensuring.food.security.in.the.
world.(Immerzeei.et.al..2010,.Sanchez.2010,.UNDP.2008).
The.origin.of.rice.paddy.ields.and.paddy.soils.is.a.topic.of.debate.among.
scientiic.scholars.around.the.world.(An.1998,.Bale.2001,.Crawford.and.Lee.
2003,.Ikehasi.2002,.Kawaguchi.and.Kyuma.1976,.Tsude.2001,.You.1995,.Zong.
et.al..2007)..The.middle.and.lower.Yangtze.River.Basin.is.a.loodplain.with.
many. rivers,. lakes,. ponds,. and. irrigation. channels,. which. are. connected.
together.known.as.the.water.network..The.spread.of.wild.rice.growing.on.
the.wetlands.and.coast.marshes.of.this.region.deem.them.as.favorable.con-
ditions. for. rice. planting,. where. the. richest. and. oldest. archaeological. fossil.
rice.grain.sites.are.also.distributed.within.this.vicinity.(about.73.7%.of.total.
sites.discovered.in.China).(An.1998,.You.1995)..The.Yangtze.River.Delta.was.
previously.the.most.important.region.for.rice.production.and.generation.of.
higher.rice.yields;.it.used.to.be.one.of.the.granary.barns.in.China..However,.
the.rapid.economic.development.and.growth.in.urbanization.over.the.past.
30.years.have.taken.their.toll.on.rice.planting.areas,.which.are.now.dramati-
cally.reduced.(Table.18.1),.resulting.in.severe.environmental.and.ecological.
problems.(Cao.et.al..2004,.Chinese.Agricultural.annals.of.the.year.1980,.1990,.
2000,.2008).
Results.from.Table.18.1.show.that.about.41.2%.of.rice.paddy.ields.were.
lost.during.the.past.30.years,.where.most.of.the.losses.occurred.in.places.
on. the. Yangtze. River. Delta,. including. Shanghai,. southern. Jiangsu,. and.
northern.Zhejiang.provinces..This.loss.is.now.the.driving.force.behind.the.
economic.development.in.China,.which.poses.the.question.of.what.effects.
will.be.incurred.in.this.region.in.the.event.of.rapid.and.extreme.reductions.
of. large. areas. of. rice. paddy. ields?. Many. scientists. have. stated. that. rice.
paddy.soil.is.a.strategy.for.sustainable.land.use.with.ecological.functions.
that.help.restore.the.biological.diversity.of.the.loodplain.(Greenland.1998,.
Masaaki.2009,.Washitani.2006)..But.is.it.a.lesson.that.can.be.learned.in.time.
by.the.current.situation.in.the.Yangtze.River.Delta?
This.chapter.reviews.major.results.from.research.on.paddy.soil.in.China.
and. abroad. conducted. over. the. past. 20. years,. intending. to. show. that. the.
Yangtze.River.Delta.may.be.the.origin.of.paddy.soils.in.China,.where.paddy.
ields.and.rice.cultivation.are.essential.to.promoting.and.preserving.a.har-
monious.ecosystem.in.this.region..In.the.past.30.years,.fast.economic.devel-
opment.has.caused.a.dramatic.reduction.in.the.proportion.of.rice.planting.
areas. and. thus. rice. output.. This. is. not. only. harmful. for. food. security. but.
also.for.ecological.safety;.therefore,.it.is.important,.from.an.environmentally.
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