DesertM o n s o o nM a k i b a

Oct. 19, 2006

DesertM o n s o o n(summer-rain area)400mm ann. rainfallGrass species with annual habit that adapt to semi-dry zone including wheat, barley and oat.Mugi-area

Tarim basinTenshan mountains

Shaohe site

DNA archaeology

Application of a restrict enzyme,

gel4X6X

Require-ment of water and fertilizerDiploid

Tetraploid

Hexaploid

Wheat consumption100-150kg / capita / year

Population in Loulan17000Productivity0.2-1t / haRequired area1700-12750 haCalculation

Much water was available3000years ago

A cow consumes 3.3 tons of grass per year(S. Kanae, personal communication)Yield of grassland = ca. 0.4 - 4 tons per hectareA cow requires ca. 0.8-8 hectare of grasslandMinimum Population Size=1000-2000Required area for cow =800-16000 hectare

28000ha

p.53)

Question:

History of desertification

Mechanisms of desertification

Literatures

In the 4th century of Loulan kingdom, food shortage became serious due to population increase. Therefore, humans begun double cropping that caused saline-soil problems due to inappropriate irrigation (Yamada, 2005)

In a kingdom he visited, more than 4000 monks lived

From S. Hedin (1934)

Shaohe20km

492050yrs

Shaohe20km

Shaohe20km

Rice zoneMap around 3000 4000 yrs. BP.Map around 3000 4000 yrs.BPMugi Zone

Conclusion:

Takramakan desert has been wetland that wheat agriculture and stock-farming practiced. A kingdom in this area, Loulan (ca.1600-2400BP.) had fertile land of at least ca. 17 sq.km for wheat, and 8sq.km for cattle. Desertification of Takramakan desert was caused at least partly by human activities, such as heavy irrigation or waste of water.

Climate changeBreedingIrrigationGenetic erosionChemicalsLoss ofSpecies-diversityEpidemicDesertificationEpidemic(humans)DeforestWater problemsProblem soils