During the Spring and Autumn Period and the Warring States Period, the feudal lords fought for hegemony, and the war broke out, so people had a further understanding of the importance of agricultural production. Thinkers at that time all put forward their own views on the importance of agriculture, among which Guan Zhong's view is the most representative. Guan Zhong not only has the famous phrase "knowing etiquette for officials, knowing honor and disgrace with ample food and clothing", but also connects agricultural production with the prosperity of the country and people. He also warned the rulers that "anyone who owns land herders should enter the warehouse at four o'clock." Based on this understanding, some vassal States put forward the slogan of "Farming War" to support the war by encouraging farmers to develop agricultural production and increase grain output. Among them, the practice of Qin State is the most successful. History: "Qin Xiaogong used the Shang Jun, bad mines, open buildings, and the rewards for emergency farming. Although it is not an ancient road, it is still a service and a neighboring country. " The victory of Qin State is actually the victory of agriculture.

While some vassal States actively devoted themselves to encouraging farmers to engage in farming wars, some thinkers also put forward their own views on agricultural issues from different positions and became farmers and one of the hundred schools at that time. Hanshu Yiwenzhi said:

Agricultural flow, Gai comes from agricultural officials. Sow 100 seeds, and advise to plant mulberries, so as to have enough food and clothing, so the eight governments say that they eat goods. Confucius said that "food is the most important thing for the people" has its own advantages. What the contemptible people did thought that the sage had nothing to do, and they wanted to make the monarch and his subjects work together to keep the order up and down.

It can be seen that farmers in the pre-Qin period can be divided into two factions: one faction has the color of "official agronomy" in its theory; The theory of the other school has the color of "light agriculture" or "civilian agriculture". Whether it is a farmer with the color of "official agriculture" or a farmer with the color of "light agriculture", his theory should include two aspects, on the one hand, his views on social politics, and on the other hand, his understanding of agricultural science and technology.

There are 9 kinds of agricultural works in Han Shu Literature and Art Annals, among which 20 pieces of Shennong and 7 pieces of Yelao 17 belong to the Six Kingdoms period. The former is that "the philosophers are sick, lazy to farm, cultivate their farmers and entrust them to Shennong." The latter, according to Ying Shao, a native of the Eastern Han Dynasty, was named "Wild Old Man" because he lived in the field and plowed with the people. And these works are now lost. Up to now, only four agricultural documents in the pre-Qin period have been preserved, namely, Shang Nong, Man and Land, Lun Tu and Shen Shi in Lu Chunqiu, which were classified as miscellaneous by Han Shu Yi Wen Zhi.

Lu Chunqiu Nong means "respecting agriculture", and expounds the importance of agricultural production and the policies and measures to encourage agriculture and mulberry. Ren Di et al. is the most concentrated and in-depth set of papers on agricultural science and technology in pre-Qin literature. It discusses a set of specific agricultural technologies and principles from aspects of arable land, soil preparation, sowing, seedling fixing, intertillage weeding, harvesting and farming time, and is very rich in content. Among them, Rendi has the nature of general discussion, while Lun Tu and Lun Shi have the nature of separate discussion. Ren Bishi put forward ten major problems in agricultural production and the general principle of land use, that is, "land to the tiller", and also discussed the importance and methods of mastering farming time. "Soil Debate" mainly focuses on cultivation techniques and methods, which is the so-called "cultivation way". First of all, talk about some principles of "arguing soil" and farming. Let's talk about the prevention of "three thieves" in farming and cultivation, that is, stealing land, stealing seedlings and stealing grass. There is an urgent need to talk about the harm of unreasonable structure. I will talk about the technical principles of sowing and intertillage in turn. Judging Time mainly discusses the importance of mastering farming time.

The appearance of three articles, such as Rendi, indicates that the traditional intensive cultivation technology has taken shape. Intensive cultivation in this period mainly has the following characteristics:

1, deep ploughing. During the Spring and Autumn Period and the Warring States Period, iron farm tools began to be widely used, which was confirmed by historical documents and archaeological excavations. At the same time, Niu Geng also appeared. All these have prepared conditions for the intensive management of agricultural production. During the Warring States period, deep ploughing was widely advocated. Deep tillage requires that "its tillage depth must be obtained in dark soil". The advantage of this is that the cultivated land can be "without big grass and moths, and now it is beautiful, beautiful." In addition to the requirement of depth, Lu Chunqiu Rendi also puts forward the general principles and some specific principles of tillage adjustment according to the soil itself. "Lu Chunqiu Rendi" says: "The tiller is generous: the strong want to be soft, and the soft want to be strong; Those who rest want to work, and those who work want to rest; People with thorns want to be fat, and fat people want to be thorns; People who are in a hurry want to slow down, and slow people want to worry; Wet to dry, dry to wet. " The general meaning of this passage is: hard soil should make it softer and soft soil should make it harder; Land that has been fallow should be cultivated, and land that has been cultivated for many years should be fallow; The barren land should be made fat, and the over-fat land should be made thin; Let it be loose if it is too real, and let it be real if it is too loose; Too wet land should make it drier, and too dry land should make it wetter. This shows that considerable experience has been accumulated in soil farming during the Spring and Autumn Period and the Warring States Period.

2. Mu. During the Xia, Shang and Zhou Dynasties, a ridge tillage method for drainage and flood prevention was formed, sometimes called "mu". During the Spring and Autumn Period and the Warring States Period, the ridge-and-acre method was developed and became a method of planting acres. Besides drainage and waterlogging prevention, it also paid attention to drought resistance and moisture conservation. This is what Ren Di put forward, that is, "abandoning acres in the fields and abandoning fields in the fields". "Abandoning fields and acres" means planting in ditches, not on the ridges of Gaotian, which is beneficial to drought resistance and soil conservation. "Abandoning farmland" refers to planting crops on the ridge (mu) in low-lying land, which is beneficial to drainage.

Lu Chunqiu also put forward specific requirements for mu and block. For example, "Therefore, Mu wants to be broad and flat, and wants to be small and deep; The sun is cloudy, then salty. " It means that ridges should be wide and flat, and ditches should be narrow and deep. The cultivation of mu has its supporting farm tools, and the specifications of mu are subject to the farm tools it uses: "Therefore, an acre of six feet is A Mu, and its size is eight inches." (Rendi) Regarding the internal structure of the ridge, it is put forward that "crops want to grow in dust, but they are stronger than hard", that is, to create a plough layer structure of "upper deficiency and lower solid" and create a good soil environment for crop growth and development.

3. Be careful. "Lv's Spring and Autumn Annals" puts forward that agricultural production should eliminate "three thieves", one of which is to eliminate "stealing seedlings", that is, to eliminate the phenomenon that seedlings bully seedlings and hinder each other because of too dense sowing and no branches. To put an end to stealing seedlings, we should start with sowing, and "be careful with seeds, don't count them, don't dilute them", that is to say, the sowing amount should be appropriate, not too dense or too dilute. It is also necessary to determine the planting density according to local conditions. "Fertilizer can't help the tree, and the tree doesn't want to live alone, so it needs to get married", that is, the fertile land should be dense and the barren land should be sparse. Otherwise, "if you are fat, you will be in batches, and if you live alone, you will die." This is the earliest discussion about the principle of reasonable close planting. In the row spacing of plants, "horizontal (horizontal) and vertical balance" is required, so as to achieve "correct behavior, ventilation, # heart (need) heart, handsome for the wind". It is required to arrange vertically and horizontally to ensure the ventilation of the site, even in the middle of the site, it can be blown without closing. This shows that there was the concept of equidistant whole seedling at that time. With regard to the requirements of covering soil, the article "On Soil" points out that "soil should not be insufficient or excessive", that is, the thickness of covering soil should be appropriate, neither too much nor too little, but solid. "Thick soil will make the tiller impassable, and thin soil will be fat but not fat." In fact, at that time, in addition to the provisions on the thickness of covering soil, the requirements for covering soil were more divided into "disease" and "maturity", that is, breaking soil and covering seeds. However, disease and maturity need to break the clods immediately after deep ploughing and cover them with fine and uniform soil.

4. simple. Clock, also known as cloud. That is, during the Warring States period, the requirements of easy tillage and cooked tillage were put forward, and the weeding of intertillage was required to be fast and fine. Only in this way can we put an end to stealing grass. But the significance of intertillage is not only here, because the ancients had to interplant seedlings during intertillage. The Book of Lu's Debate on Land in the Spring and Autumn Period points out: "Miao people are weak, want to be lonely, grow up, live together, be familiar with each other and help each other." So three people regard it as a family, but a lot of millet. " Based on the growth dynamics of crops, the standard of reasonable close planting is pointed out, that is, at seedling stage, seedlings should be isolated from each other to make them have sufficient growth space; When they grow up, they just let the plants get close to each other, which is equivalent to the so-called "closed line" in modern times; At maturity, due to the increase of tillers (three families), plants are close to each other, which can not only prevent lodging, but also make maximum use of soil fertility and sunshine, thus ensuring the highest yield (more millet). In order to meet this standard, there are seedlings. Interplanting is mainly carried out by intertillage weeding. "The handle ruler is also a degree, and its (Bo) is six inches, so it is also a stubble." ("Rendi") When thinning seedlings, it is also necessary to "grow his brother and go to his brother", that is, to require thinning seedlings. Because "the gentleman is beautiful, the younger generation is clumsy."

5. judge the time. A major feature of agricultural production is its strong seasonality. Mencius said, "If you don't go against the farming season, you can't beat grain." "Lu Chunqiu Review" said: "Always plant grains, and if you don't fold, you will reap. If you don't harvest when you are ripe, you will encounter natural disasters. " "Where the way to plow, thickness (waiting) is a treasure." The book discusses the different effects of sowing date, early sowing date and late sowing date on the yield and quality of six crops in turn. Finally, from the comparison of yield and quality, the conclusion that "the crops are prosperous when they are in time, and the crops are shrinking when they are out of time" is demonstrated. This is aimed at the sowing date, in fact, every link of agricultural production has time requirements. As far as farming period is concerned, there are different farming periods because of different soil quality. The "ridge soil" with heavy soil quality should be cultivated first, and the "weathered soil" with light soil quality can still be cultivated later. In order to determine the suitable ploughing period, Lv's Spring and Autumn Annals also summarized the experience of determining the ploughing period according to phenology, and pointed out: "On the seventh day of the 50 th day after winter, Acorus calamus began to grow, and Acorus calamus was the king of all kinds of herbs, so ploughing began." This is based on the phenological characteristics of the birth of Acorus calamus, as a sign of the beginning of suitable farming period.