grain yield per unit area

Since 1987, late rice is planted in extensive area. The meteorological factors influencing the variation of grain yield per unit area from 1987 on differ obviously with those before 1987.

1987年大面积种植单季晚稻以来，影响粮食单位面积产量变化的气象条件与1987年之前有着明显的差异。

Grain yield per unit area increased continually during the past near 50 years in HuangHuai -hai plain, and its increasing speed in recent years still kept higher than the average of all the country.

建国以来黄淮海平原粮食单产持续增长，近年来仍然高于全国同期单产增速。

We must protect primary farmland, keep the area sown to grain stable, improve the structure of grain varieties grown and increase the per unit area yield of grain.

要保护好基本农田，稳定粮食播种面积，优化粮食品种结构，着力提高粮食单产。