2017年6月21日,丁酉夏至,天渐暑热。古历书曰:夏至,“一候鹿角解;二候蝉始鸣;三候半夏生。”古人以五天为一候,夏至日阴气生而阳气始衰,五天内阳性的鹿角便开始脱落;五天后,出土的雄蝉因感阴气之生便鼓翼而鸣;十天后喜阴的药草半夏会在仲夏的沼泽地或水田中长出。古人向以周遭万物生发变化来记录季节农时,《夏小正》《吕氏春秋》《汜胜之书》《齐民要术》等书 June 21, 2017, Ding You summer solstice, gradually getting hot. The ancient calendar reads: the summer solstice, “an antlers solution; two cicadas begin Ming; three half-summer.” The ancients to five days as a wait, the summer solstice yin-yang and yang qi decline, within five days of positive antler Began to fall off; five days later, unearthed male cicada because of the feeling of yin-yang will drumming and Ming; ten days after the shade of herbs Pinellia summer in midsummer or paddy fields grow. When the ancients recorded seasonal agriculture with the changes of germination around the world, Xia Xiaosheng, Lu’s Spring and Autumn Annals, The Book of Qingsheng, Qi Min Yao Shu and other books