稻麦作物净初级生产力模型研究:模型检验与情景预测

Simulating Net Primary Production of Rice and Wheat Crops: Model Validation and Scenario Prediction

利用我国若干代表性区域 98组稻麦作物生产力的试验数据 ,对所建立的稻麦作物净初级生产力模型进行了检验 .结果表明 ,该模型能根据常规的气象和土壤资料、化肥施用量等数据资料较好地模拟我国主要区域稻麦作物的净初级生产力 .模拟值 (y)与观测值 (x)的线性关系为 :y =1 .0 5x - 16 . 8(r2 =0 .771,p <0 . 0 0 1,n =98) .对南京地区的情景预测结果表明 :大气CO2 浓度升高促进稻麦作物的固碳能力 ;气温升高会降低水稻和小麦的碳固定 ,但对小麦的影响要小于水稻 ;在当前情景及未来情景 (CO2 浓度为 5 4 0 μmol·mol-1,温度增加 1～ 4℃ )下 ,氮肥施用对小麦碳固定的促进作用大于水稻 ,氮肥施用量高于 15 0kg·hm-2 时对 2种作物的碳固定没有显著的促进作用 ,甚至降低水稻的净初级生产力 .

A model developed by the authors was validated against a total of 98 independent data sets to simulate net primary production (NPP) of rice and wheat crops. These data sets come from literature review and include field measurements conducted in different regions of China with various rates of N application. Model validation indicates that NPP of rice and wheat crops in main cultivated-area of China can be well simulated from weather, soil and N fertilization. A comparison between the simulated (y) and the observed NPP (x) resulted in a regression of y=1.05x-16.8 (r2=0.771,p<0.001,n=98). Model scenario prediction for Nanjing area suggests that the increase of atmospheric CO_2 concentration will enhance carbon fixation, while the increase of air temperature will reduce carbon fixation by rice and wheat crops. Effect of global warming on the wheat carbon fixation is less than on the rice. Under present and future scenario with atmospheric CO_2 concentration of 540μmol·mol -1 and temperature increment of 1～4℃, N fertilization will enhance carbon fixation of rice and wheat crops. The enhancement for wheat is more significant than that for rice crop. However, the application of N will not significantly improve the carbon fixation, even reduce rice NPP when the N application rate is higher than 150 kg·hm -2.