农业生产力模型初探

根据植物的生理生态学特点及诸气候要素建立了农业净第一性生产力模型:NPP=exp(rR_n(r~2 R_n~2 rR_n/(R_n r)(R_n~2 r~2)·(0.0015RDI 0.0013)) 用该模型对全球变化条件下的农业净第一性生产力的敏感性试验表明:我国农业净第一性生产力在气温升高2℃且降水不变或增加20％的情况下都有不同程度的提高,幅度为0.44％～12.88％,其中,在降水不变的情况下,湿润地区增加幅度最大,为5.46％～12.88％,在降水增加的情况下,干旱、半干旱地区增加幅度最大,为3.89％～10.92％;在温度升高2℃、降水减少20％的情况下,湿润地区农业生产力增加1.48％～14.63%,干旱、半干旱地区农业生产力降低0.44%～2.92％,干旱地区降低幅度较大,为1.04％～6.01％,表明水分为农业生产力的主要限制因子。

AN AGRICULTURAL NET PRIMARY PRODUCTIVITY MODEL

A net primary productivity (NPP) model of agricultural vegetation was presented based on the ecophysiological feature of plants and climatic factors: This model was used to simulate the NPP of agricultural vegetation according to the comparison between the observed agricultural NPP data from 27 provinces and cities and the simulated data, which were in good agreement. The sensitivity study of agricultural vegetation was also done with the new NPP model in China. The results showed that the crop productivity would increase by 0.44% to 12. 88 % in China when the temperature increased by 2C and precipitation unchanged or increased by 20% . It would increase by 5.46% to 12.88% in moist area when precipitation change and increased by 4.15% to 10.92% in arid and semiarid areas when precipitation increased by 20%; and it would increase by 1.48% to 14.63% in moist area, decrease by 0.44% to 6.01% in arid and semiarid areas especially in arid area when the temperature increased by 2C and precipitation decreased by 20% . This indicated that water was a key factor to agricultural vegetation. The new NPP model would help us to understand and forecast agricultural development, to organize agricul- tural activity effectively, to make good use of agricultural resources, and to increase lands capacity.