The Nongjia 農家 "agriculturalists" were a philosophical school, one of the "hundred schools" (baijia 百家) that flourished during the Warring States period 戰國 (5th cent.-221 BCE). Its most important representative was Xu Xing 許行. His propositions were that everyone, even the nobility, had to participate in the production of food and other agricultural products and to cook his own food (bing geng er shi, yong can er zhi 并耕而食，饔飧而治 "cultivate the ground equally and along with their people, and eat the fruit of their labour", transl. Legge). Such an idealistic model of equal status of all members of society had no chance of realization in a world where everyone had the chance to social mobility by military or political merits.
Xu Xing's theories were also not appreciated by Confucians like Mengzi 孟子, who explained that "those who labour with their minds govern others; those who labour with their strength are governed by others." Xu Xing, who hailed from the state of Chu 楚, once met to a dispute with Mengzi at the court of Duke Wen of Teng 滕文公 (r. 600-575) where he argued that everyone had to life the same life as during the times of the "Divine Husbandman" Shen Nong 神農, and that the prices on the markets were to be fixed (shi jia bu er 市賈不貳 "there would not be two prices in the market"), so that no one would be cheated. Mengzi rebuked his theories by demonstrating that a modern society necessarily adhered to divison of labour, because if everyone is a farmer, no one will produce iron ploughs or clothes. Some historians identified him with Xu Fan 許犯, a later disciple of Mozi 墨子.
The agriculturalists were very interested in the promotion of better techniques in agriculture, which is therefore a field where they substantially contributed to the enhancement of production in later years. Their school of thought was the origin of the vast treasure of books on agriculture written in later ages. Their authors were subsumed under the term nongjia "experts on farming". The early texts Shen Nong shu 神農書 and Yelaoshu 野老書 are lost except a few fragments.
Apart from in the book Mengzi, fragments of agriculturalist thinking are to be found in the Guanzi 管子, Shanghunshu 商君書 and Lüshi chunqiu 呂氏春秋.
Chen Ying 陳瑛, Xu Qixian 許啟賢 eds. (1989). Zhongguo lunli da cidian 中國倫理大辭典 (Shenyang: Liaoning renmin chubanshe), 294.
Gao Liushui 高流水, He Wenge 何文格 (1996). "Xu Xing 許行", in Feng Kezheng 馮克正, Fu Qingsheng 傅慶升, eds. Zhuzi baijia da cidian 諸子百家大辭典 (Shenyang: Liaoning renmin chubanshe), 26.
Nongye da cidian bianji weiyuanhui 農業大詞典編輯委員會, ed. (1998). Nongye da cidian 農業大詞典 (Beijing: Zhongguo nongye chubanshe), 1182, 1877.