What best represents the level of China's ancient fertilization technology?

The most representative of China's ancient level of fertilization technology is the emergence of the Ming and Qing dynasties, rice paddy seedling fertilization technology. This technology first appeared in the Taihu Lake region of the Hangjiahu Plain. According to "Shen's agricultural book" records: "cover the life on the field, all easy, only relay a congestion, must phase its time, check its color, the most important organs for farmers." Here, "phase its time", "check its color", in today's words, is to look at the developmental stage of crop growth and nutritional status to decide, that is, what we call look at the seedling fertilizer.