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 is 5 juan "scrolls" long and was written by a certain Han E 韓鄂, also written 韓諤, of which virtually nothing is known. He lived at the end of the 9th century and was distantly related to Han Xiu 韓休, a Counsellor-in-chief of Emperor Xuanzong 唐玄宗 (r. 712-755). The Sishi zuanyao is not included in the imperial bibliography of the official dynastic history Jiutangshu 舊唐書, but in that of the Xintangshu 新唐書, and in many Song period 宋 (960-1279) bibliographies.
The book contains 698 paragraphs dealing with divination of time and auspicious days, production of agricultural goods (grain, oil, fibres, vegetables, bran, dyestuffs, mulberry and other trees, fruits, bamboo) and raising cattle and various domestic animals (including fishes and bees), the processing of agricultural goods (the retting of flax, brewing wine, the production of treacle, dairy produce, starch processing, that of animal fats, pickling, and storing), the manufacturing of agricultural tools, implements, special clothes (oilcloth, leather cloth), lacquerware, ink and colours for painting, the marketisation of agricultural goods, the production of crops and herbs that can serve as materia medica (cultivation, harvesting, processing and storing of medical drugs; ointments and cosmetics), as well as cultural aspects like education, mantics, or disaster relief. The text is arranged in a chronological sequence according to the ancient text "Monthly commands" (Yueling 月令, part of the Classic Liji 禮記) that described the seasonal activities of farmers. The text quotes extensively from older books like Fan Shengzhi shu 氾勝之書, Simin yueling 四民月令, Qimian yaoshu 齊民要術, Shanju yaoshu 山居要術, Weishi yuelu 韋氏月錄, Baosheng yuelu 保生月録 or Dilijing 地利經, but also adds some information that is based on the author’s own experience.
The Sishi zuanyao is an important and comprehensive text because it fills a chronological and technical gap between the book Qimin yaoshu from the Northern Dynasties period 北朝 (386~581) and the large agricultural encyclopedias of the Song period 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 older texts, there are some newly introduced crops included in the Sishi zuanyao, like cotton, certain kinds of mushrooms, tea, dates, wine, or information how to how to keep bees. It is also the first Chinese book describing the process of fermenting soy beans (chi 豉) and soy sauce production. The cultivation, harvesting and marketization of tea is described much more precise than in Lu Yu's 陸羽 famous "Tea Classic" Chajing 茶經. Han E explains the advantage of cultivating several crops in one field, like large gourds (da hulu 大葫蘆), lucerne (muxu 苜蓿) and wheat (mai 麥), or nettle-hemp (xima 枲麻), tea sprouts (chamiao 茶苗) and millet (shuji 黍穄). The cultivation of ginger (shengjiang 生姜), yam (shuyu 薯蕷) and various kinds of mushrooms is for the first tiem described in the Sishi zuanyao, as well as that of lotus (ou 藕, i.e. lotus roots, and lian 蓮, lotus sees), Gorgon euryale (qian 芡), water chestnut (biqi 荸薺), kudzu hemp (ge 葛), lilies (baihe 百合), Poris cocos (fuling 茯苓), oriental water plantain (zexie 澤瀉) and puncture vine (jili 蒺藜). Differences between southern China and the north are explained, for instance, in the braided "cooling mats" (tanxi 覃席) and banana leaves (jiaoge 蕉葛) of the south, and the custom of the southerners to always take with them artemisia pills (yinchen wan 茵陳丸) in their "first-aid kit".
The Sishi zuanyao represents techniques of running a large-scale farm as an enterprise and gives insight into the daily business of the land-owning elite of the Tang period that does not differ much from earlier centuries. The author of the Sishi zuanyao explains that farming is the base of all livelihood. Only if the granaries and storehouses are full, he says, people can mentally care for rites and propriety (cang lin shi, zhi li yi 倉廪實，知禮義).
The Sishi zuanyao was first printed in 996 but 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. This copy was published by the Yamamoto shoten 山本書店 press in 1961. Miao Qiyu 繆啟愉 wrote a commentary (Sishi zuanyao jiaoshi 四時纂要校釋), published in 1981. Only a small part of the original text seems to be lost, while some other paragraphs appear to have been inserted at a later date.