中国农业植被净初级生产力模拟(I)——模型的建立与灵敏度分析

以业已建成的稻麦作物净初级生产力模型为基本框架,建立了一个具有普适性的中国农业植被净初级生产力模型(CropC-)。CropC-的模拟对象为占我国农作物总播种面积2/3的水稻、小麦、玉米、棉花、油菜和大豆。该模型包括2个主要功能模块:光合作用和呼吸作用;土壤-作物系统氮素运移。前者综合考虑了环境因子和氮素的影响,后者包括了作物氮素吸收、土壤氮矿化和化肥氮释放。灵敏度分析表明,在输入参数变化±10%时,CropC-对6个主要输入参数响应的敏感性依次为温度>光合有效辐射>大气CO2浓度>土壤全氮含量>施氮量>降水。模型分析表明,气候变暖将降低作物净初级生产力。

Simulating Net Primary Production of Agricultural Vegetation in China (Ⅰ): Model Establishment and Sensitivity Analysis

Plant net primary production(NPP) of agriculture vegetation represents the capacity of sequestrating atmospheric CO2 in agro-ecosystem,and plays an important role in terrestrial carbon cycling.In comparison with natural ecosystems of forest and grassland,agro-ecosystem is much complex due to human activities.To better understand the contribution of agro-ecosystem to regional carbon budget,the simulation models of crop NPP have been developed well since the 1970s.However,few models are successfully put into practice in the agro-ecosystem of China,being mainly due to the unavailability of model inputs and the verification of reliability in different regions of China.The objectives of this paper are to establish a crop NPP model that could be put into practice in the agro-ecosystem of China and to make sensitivity analysis of the model. In light of a preliminary model established by the authors that simulates NPP of rice and wheat crops,a model named as Crop-C was developed.Crop-C is dedicated to the simulation of NPP of those crops of rice,wheat,maize,cotton,rapeseed and soybean planted in approximately two-thirds of agricultural soils in China.The model includes two main functional modules:photosynthesis and respiration,and nitrogen transport within soil-plant system.The processes of photosynthesis and respiration are mainly driven by environmental variables of temperature,solar radiation,precipitation,atmospheric CO2 concentration and crop tissue nitrogen.The transportation of nitrogen within soil-plant system is determined by simulating the processes of crop nitrogen uptake,soil nitrogen mineralization and synthetic nitrogen release. Model sensitivity analysis suggests that the sensitive significance of Crop-C to input parameters is in descending order of temperature,PAR,atmospheric CO2 concentration,soil nitrogen concentration,rate of nitrogen application and precipitation when the input parameters vary at-10% and 10%,respectively.In addition,global warming would have a negative effect on NPP of agricultural vegetation in China based on the model sensitivity analysis.