Abstract:

The contribution factors of the change of grain yield per unit area are clarified to provide coping strategies for food security in poor mountainous areas. Taking Yunnan Province as an example, based on the grain production data from 1989 to 2018, using the RLI model, this paper constructs a factor decomposition model for the change of grain yield per unit area, and calculates the contribution factors of grain yield change in Yunnan Province from the perspectives of crops and regions. The results show that: the grain yield per unit area in Yunnan presents an obvious upward trend, and the stability of the change is enhanced. The primary contribution factor of grain yield increase in Yunnan is the improvement of grain yield per unit area, with an average contribution rate of 82.21%, but the role of structural effect should not be underestimated. From the perspective of crops, corn and potato have the greatest combined effect, with the contribution rate of 134.89%. From the regional perspective, Baoshan, Zhaotong, Xishuangbanna, Wenshan, Lincang and Dehong play a leading role. When consolidating the achievements of poverty alleviation, governments at all levels in poverty-stricken mountainous areas should properly handle the relationship between industrial poverty alleviation cash crops and food crops, optimize the industrial structure of advantageous areas for grain production, increase research and development investment in new varieties and technologies of grain, accelerate the improvement of grain technology extension system, and strengthen the grain reserve and emergency mechanism in poor mountainous areas.

Key words: Yunnan, refined laspeyres index model, grain, yield per unit, factor decomposition