The Sishi zuanyao 四時纂要 "A compilation of important [activities] during the four seasons" is an agricultural treatise from the Tang period 唐 (618-907). It comprises 5 juan "scrolls" and was written by a certain Han E 韓鄂 of which virtually nothing is known. He lived at the end of the 9th century. The book contains 699 paragraphs dealing with divination, production of agricultural goods and raising cattle, the processing of agricultural goods, the manufacturing of agricultural tools, marketisation of agricultural goods, and the production of crops and herbs that can serve as materia medica.
The Sishi zuanyao is so important because it fills a chronological and technical gap between the book Qimin yaoshu 齊民要術 from the Northern Dynasties period 北朝 (386~581) and the large agricultural encyclopedias of the Song period 宋 (960-1279), like Chen Fu's 陳旉 Nongshu 農書 "Book on agriculture". Although a lot of information on early Chinese agriculture can also be found in the older texts, there are some new crops included in the Sishi zuanyao, like cotton, mushrooms, tea, dates, wine, or how to nourish bees. It is also the first Chinese book describing the process of soy sauce production by adding ferments.
The Sishi zuanyao was lost at an early date. In 1960 a Korean print from 1590 was discovered in Japan which was itself a reprint from a Chinese edition printed in 996. Miao Qiyu 繆啟愉 wrote a commentary (Sishi zuanyao jiaoshi 四時纂要校釋), published in 1981.
Source: Sha Zhi 沙知 (1992). "Sishi zuanyao 四時纂要", in: Zhongguo da baike quanshu 中國大百科全書, Zhongguo lishi 中國歷史, vol. 2, p. 967. Beijing/Shanghai: Zhongguo da baike quanshu chubanshe.