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Four environmemtal service functions of wheat, barley and rape ecosystem are evaluated in material production, air adjustment (including carbon dioxide fixation and oxygen release in Tibetan Autonomous Region), water conservation, and nutrient recycling. Based on it the economic loss of environment due to desertification is valued. The results show that the service functions of farmland ecosystem in Tibet are totally valued at 4 436. 2 × 106 yuan, the value of each service function is ordered as: air adjustment 2 070.2× 106 yuan (46.67%), material production 2 011. 1× 106 yuan (45.33%), nutrient recycling 193. 1×106 yuan (4.35%), and water conservation 161. 8×106 yuan (3.65%). The total area of wheat, barley and rape in Tibet is over 189 700 ha, and the service function of farmland ecosystem is valued at 23 386 yuan/ha per year. The degraded area of arable land in Tibet is about 1 082 ha per year, equivalent to the annual loss of farmland ecosystem service value of 25.3×106 yuan. Over the past 30 years the total loss of the value is 1 347.0×106 yuan.
Four environmemtal service functions of wheat, barley and rape ecosystem are evaluated in material production, air adjustment (including carbon dioxide fixation and oxygen release in Tibetan Autonomous Region), water conservation, and nutrient recycling. Based on it the economic loss of environment due to The results show that the service functions of farmland ecosystem in Tibet are totally valued at 4 436. 2 × 106 yuan, the value of each service function is ordered as: air adjustment 2 070.2 × 106 yuan (46.67%), material production 2 011. 1 × 106 yuan (45.33%), nutrient recycling 193. 1 × 106 yuan (4.35%), and water conservation 161. 8 × 106 yuan (3.65%). The total area of wheat, barley and rape in Tibet is over 189 700 ha, and the service function of farmland ecosystem is valued at 23 386 yuan / ha per year. The degraded area of arable land in Tibet is about 1 082 ha per year, equivalent to the annual loss of farmland ecosystem service value of 25.3 × 106 yuan. Over the past 30 years the total loss of the value is 1 347.0 × 106 yuan.