Ecosystem Health, Conservation and Restoration

• At the southern end of the Great Plains is the huge, nearly flat plateau known as the High Plains, which extends southward from the northern border of Nebraska through the Panhandle of Texas, and forms the central part of the Great Plains.

• The east and west rims of the southern High Plains are at high, cliffed, erosional escarpments--the Caprock escarpment on the east and the Mescalero escarpment on the west.

Land Use and Ecosystem Health• 1862 Federal Homestead Act, large tracts of rangeland were

converted to cropland• The bare surfaces left by the early tillage techniques led to

extensive wind and water erosion –Dust Bowl years in 1930’s.

• Ecosystem conservation programs were developed and cultivation systems were adopted to reduce erosion, decrease soil disturbance, enhance water storage, and encourage more efficient water use.

• Establishment of the Conservation Reserve Program (CRP) aimed at ensuring success of the conservation effort. In 1991 the Great Plains contained 70 percent of the total U.S. cropland acres enrolled in major farm support programs, and 73 percent of the total acres in CRP.

Taiyuan loess plateau in China, The yellow river and wind carry yellow soil (loess) spread silt on the land to create miles of fertile farmland. Taiyuan plateau offered protection and fertile loess soil for the farming community to develop some 6000-9000 years ago. Following thousands years of cultivation, this once glorious plateau is largely fragmented from erosion

Do you know why the Yellow River basin is called the Cradle of Chinese Civilization?

Shanxi, Xingxian showing ridge-and-mound landform.

For the most part, the loess plateau is badly dissected by gullies due to erosion, and its features are generally referred to as thousands of hills and ten folds more gullies.

Source: Land Resources in the Loess Plateau of China, edited by TheNorthwest Institute of Soil and Water Conservation, Academia Sinica, pub by Shaanxi Science and Technique Press, 1986.

Dongzhiyuan in Gansu is the largest piece of intact tableland in existence

Source: Land Resources in the Loess Plateau of China, edited by TheNorthwest Institute of Soil and Water Conservation, Academia Sinica, pub by Shaanxi Science and Technique Press, 1986.

This piece of tableland is being eroded steadily; we guess that the road way was once straight just possibly 40 years ago.

Source: Land Resources in the Loess Plateau of China, edited by TheNorthwest Institute of Soil and Water Conservation, Academia Sinica, pub by Shaanxi Science and Technique Press, 1986.

Gansu, Zhengning's tai yuan tableland

Source: Land Resources in the Loess Plateau of China, edited by TheNorthwest Institute of Soil and Water Conservation, Academia Sinica, pub by Shaanxi Science and Technique Press, 1986.

Gansu, Qingyang's tai yuan tableland

Source: Land Resources in the Loess Plateau of China, edited by TheNorthwest Institute of Soil and Water Conservation, Academia Sinica, pub by Shaanxi Science and Technique Press, 1986.

Shaanxi, Luochuan: landform in transition from tai yuan tableland to elongated mounds

Source: Land Resources in the Loess Plateau of China, edited by TheNorthwest Institute of Soil and Water Conservation, Academia Sinica, pub by Shaanxi Science and Technique Press, 1986.

Soil biota and exotic plant invasion

Ragan M. Callaway, Giles C. Thelen, Alex Rodriguez & William E. Holben

Division of Biological Sciences, The University of Montana, Missoula, Montana 59812, USA

Nature 427, 731 - 733 (19 February 2004)

• Centaurea maculosa, a spotted knapweed and a European native that has spread to all 50 US states since its introduction in the late 1800s.

• They compared the feedback effects that arise between the plant and soil microbes when it is grown in soil taken from its native versus adoptive habitat.

• Soil microbes from the plant's home range have stronger inhibitory effects on its growth than do those from its US habitat. – Sterilization of European soil resulted in a 166% increase in plant biomass

compared with a 24% increase following the same treatment of soil from Montana.

– Additionally, plants grown in nonsterilized European soil were smaller if the soil had been precultured with other C. maculosa plants rather than a European grass species. Conversely, in Montana soil, plants did better in C. maculosa–primed soil.

Figure 1 Total biomass of C. maculosa plants grown in non-sterilized and sterilized soil collected from European (n = 4) and North American (n = 6) populations of C. maculosa.

Figure 2 Total biomass of C. maculosa plants grown alone in European soil (Central Massif population) and North American soil (Missoula population) that had been pre-cultured by either C. maculosa or a Festuca species native to the place of soil origin.

Conclusions

• In native European soils, Centaurea cultivates soil biota with increasingly negative effects on the weed's growth, possibly leading to its control.

• But in soils from North America, Centaurea cultivates soil biota with increasingly positive effects on itself, which may contribute to the success of this exotic species in North America.