第5讲作物生产潜力.ppt

基于食物供求和土地利用结构优化的区域土地人口承载力估算模型框图 土地利用结构和人口承载力优化 膳食指标；食物、饲料类型及其营养价值 土地利用类型与产量 食物、饲料需求优化 土地、食物、饲料平衡 食物生产总量 土地承载人口 土地利用结构 食物与饲料需求量 作物模拟、实验数据、农户调查 案例：京津冀地区和安塞县 Issues Possible reduction of farmland in the future, and thus the effects on food security Dietary change and its effects on food demand Options for food security Farmland protection: e.g., “redline of 120 million ha” as the national aim of farmland preservation; and reducing the extent of the nationwide Grain for Green program in 2006 Promotion of land productivity: subsidy to agriculture Balanced food diet Objectives Focus on an analysis of yield increasing potentials of farmland, to explore the land capacity to support population in Northern China Crop production potentials and yield gaps of major cropping systems Land population carrying capacity in consideration of land productivity and food dietary change in the future General characteristics of the case areas Total land 21.6Mha, comprising 54% hilly land and 46% plain Annual rainfall mostly 600-700mm High population density, 456 persons/s.q. km Total farmland 7.09Mha, 58% of which is irrigated Main growing crops are winter wheat and maize, covering 61% of the sowing area Total land 0.3 Mha; more than 90% is hilly loess land Annual rainfall around 530 mm Population density 56 persons/s.q km Total farmland 70 kha, 81% of which is sloping land; 98% of the farmland is not accessible to irrigation Main growing crops are maize, millet, soybean, potato, winter wheat Beijing-Tianjing-Hebei Region Ansai County Assumptions and scenario definition Balance in food/feed production and demand in terms of total energy; Based on farmland area in 2005; irrigation area was assumed no expansion Four scenarios defined, based on two yield levels and two diets Tow yield levels 60% and 75% of the potential yield for BTH, and 50% and 60% of water-limited yield for Ansai Two diets: Current diet (mean diet in 2008); Improved diet (a balanced diet recommended by the Chinese N