Grasslands of the World.pdf - Disasters and Conflicts - UNEP

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Grasslands of the world
TABLE 8.3
Botanical composition in the Chang Tang Wildlife Reserve, northern Tibet (percentage basis).
Alpine Steppe Alpine Desert Steppe
plains plains mountain
Grasses 61.9 58.8 29.8 42.7 17.5
Sedges 15.2 28.5 22.8 48.5 69.8
Forbs 17.5 10.6 35.2 6.2 9.3
Shrubs 5.4 2.1 12.2 2.6 3.4
SOURCE: Adapted from Miller and Schaller, 1997
TABLE 8.4
Botanical composition of rangeland in Hainan Prefecture, Qinghai (percentage basis).
Alpine Meadow Temperate Meadow- Steppe
Grasses 8.20 68.00
Sedges 40.70 3.87
Legumes 4.05 2.45
Edible forbs 29.33 18.68
Non-edible forbs 17.72 7.00
Total
SOURCE: Lang, Huang and Wang, 1997.
100.00 100.00
TABLE 8.5
Annual dry matter production and carrying capacity for different grassland types in Hainan
Prefecture, Qinghai Province.
Pasture type Dry matter (kg/ha) Carrying capacity (ha/SU/yr)
Alpine meadow 934 0.78
Temperate meadow- steppe 623 1.17
Alpine steppe 594 1.23
Temperate desert steppe 345 2.11
Temperate desert 228 3.19
Lowland meadow
NOTES: SU = Stock Unit.
SOURCE: Lang, Huang and Wang, 1997.
1 341 0.54
in an alpine meadow and in temperate meadow-steppe in eastern Qinghai. In
alpine meadow, grasses comprise only 8 percent of vegetation, while sedges
comprise 40 percent, with the balance being forbs. In temperate meadowsteppe,
a high proportion of vegetation (68 percent) is grasses.
GRASSLAND PRODUCTIVITY
The standing crop on the Steppe varies considerably. Alpine meadows are some
of the most productive, as average annual dry matter (DM) production may
reach 1 000 kg/ha. Productivity of desert pasture is low, averaging only 100–
200 kg/DM/ha. Table 8.5 gives annual DM production and carrying capacity
of different pasture types . Harris and Bedunah (2001), in Aksai County, Gansu
Province, found average standing crop varied from 115 kg/DM/ha in desert
shrub to 790 kg/DM/ha in desert sub-irrigated meadows (Table 8.6).
Nutrient content of herbage
On most of the steppe, natural forage is the only source of nutrients, except
for small amounts of hay and purchased concentrates, so understanding