"The white dew is early, the cold dew is late, and the autumn equinox is the time to plant wheat."

This is a summary of the experience of farmers in Huanghuai area about the sowing date of wheat hundreds of years ago.

With the advent of the modern industrial era, a large number of greenhouse gases are emitted, which leads to the continuous rise of the earth's surface temperature. Compared with ancient times, the agricultural season has also changed greatly. If we still follow the proverbial season to guide wheat planting, it will be out of date (it will lead to the over-age of wheat seedlings, which is not conducive to their safe wintering, and wheat will freeze to death in most years).

According to experts' research, the best sowing date of wheat in southern Shandong should be in the "cold dew" season (solar calendar 65438+10.5-15). When sowing in this period, the seedling age of wheat is suitable, and the probability of freezing injury is the smallest, which is beneficial to its safe overwintering.