Abstract:

The yield potentials of crops were projected in this research by three different methods: (1) the yield potentials of the majority of global crops were projected by the regression analysis of the historical annual crop yield data to be 2 to 3 times of their current yields; (2) the yield potentials of rice, wheat, maize, potato, rapeseed and soybean for China were projected by the AEZ model developed by IIASA and FAO to be 1.2, 2.2, 2.2, 2.9, 2.0 and 1.9 times of their 2005 country-wide average respectively; (3) the yield potentials of global rice, wheat, maize, potato, rapeseed and soybean were projected to be 1.4, 2.5, 1.2, 1.8, 1.9 and 2.2 times of their present record yield respectively, by the maximum light use efficiency (LUE) of plant model. The projected potential crop yields of the study indicated that the carrying capacity of global agro-ecosystem was limited. Thus, in a closed system such as the global ecological and economical system was not sustainable.