There are different factors to impact producing technical efficiency in main grain producing area;
②三种粮食作物的生产技术效率所受影响因素不同；
Huangfan Plain was the main grain-producing area ten century ago.
公元九、十世纪以前还是我国粮食生产的主要基地。
The main grain-producing area is the main body of China agriculture production, especially of grain producing.
粮食主产区是我国农业生产尤其是粮食生产的主体。
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