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First of all, environmental problems have a long history.
With the development of western industrialization in the 20th century, agricultural industrialization has also become the main theme. Since the 1970s, the developed countries have rapidly developed modern agriculture armed with oil and characterized by mechanization, chemicalization and energy utilization, and gained great benefits. Although the extensive use of machinery, fertilizers, pesticides and herbicides has improved land productivity and labor productivity and met the demand for food brought about by the rapid population expansion, a series of adverse consequences are shocking, such as environmental pollution, soil erosion, ecological destruction, simplification of animal and plant varieties and loss of germplasm resources. Increasing the application of chemical fertilizers and pesticides will not only pollute the soil environment and crops, but also enrich into the human body and affect people's health. Over-reliance on synthetic substances produced by modern technology makes it difficult for the earth to purify itself and the soil to digest. In particular, it exceeds the self-repair threshold of river water bodies, making pollution everywhere. Genetic engineering introduces foreign genes into corn, soybean, cotton, rice and other crops to make them resistant to insects and weeds, which seems to solve the problem of pesticide pollution once and for all, but it is impossible to predict the negative effects after long-term large-scale promotion. The harm of DDT residue was discovered after decades of widespread use. Today, after decades of stopping production and use, the problem still exists. Therefore, developed countries have taken actions to seek a way out for sustainable development. As a big agricultural country, China's population growth, environmental deterioration, resource shortage and other issues are becoming increasingly serious. The issue of sustainability needs people's attention in particular.
In fact, as early as 1962, American Carson declared a terrible reality, the silent spring came out. Although the phenomenon pointed out by Carson is not entirely caused by agriculture, agriculture should occupy its main component. Subsequently, the "Human Environment Conference" held in 1972 adopted the "Declaration on Human Environment" and put forward
Earlier, in the United States, the serious decline of soil fertility in the early19th century prompted the American government to find a solution. From the early18th century, the British cultivated land and cut down forests in America. After independence, the United States inherited the characteristics of extensive agricultural management in medieval Europe, which was aggravated by the contradiction between the lack of labor and the infinite richness of land. Farmers blindly cultivate and harvest. It is considered that the arable soil is boundless and does not care about how to maintain soil fertility. As Thomas Jefferson said, "People are reluctant to fertilize because it is cheaper to buy an acre of new land than to fertilize it" [1]. Because of the low population base at that time, the contradiction between agriculture, especially land resources, resource utilization and environmental protection was not very prominent. However, by the beginning of the 20th century, it was less than 100 after American independence. There have been serious soil erosion caused by vegetation destruction and soil fertility decline caused by improper land use and farming. The American government has to look for solutions to this problem everywhere. They worry that the population density in China is much higher than that in the United States. The problem of sustainability is not that serious. So in 1909, the federal government sent soil scientist Franklin hiram King to China to find valuable experience of traditional agriculture. With the keen eye of an agricultural soil scientist, the agriculture and rural areas in China were investigated in detail. After returning to China, he wrote Farmers in the Fortieth Century or Permanent Agriculture in China, Korea and Japan, introducing China's long-standing agricultural achievements in the past 4,000 years. The unique ideas of intensive cultivation, crop rotation and soil and water conservation, that is, the rational crop rotation, manure application and composting of traditional Chinese agriculture centered on leguminous plants are worth learning by American farmers, put forward the original idea of organic agriculture [2]. Under the background that countries all over the world, especially the western countries, have not fully understood the oriental agriculture, this book has aroused great concern from the agricultural circles in the United States and has had a far-reaching impact, especially on those who later engaged in organic agriculture, including Howard in Britain and Rodale in the United States.
However, the publication of this book has not solved the existing environmental problems. In the United States, by 1933, at least 50 million acres have become barren, and1250,000 acres have been reduced due to erosion. A disastrous black storm swept away 300 million tons of soil in 1934, which reduced the yield of winter wheat by 102 billion.
The situation in America in the 20th century was really bad. In China, this problem appeared earlier, and similar environmental problems appeared as early as the pre-Qin period. Mencius has long pointed out that the reason why Niu Shan in the southeast of Qi is "a mountain full of children's mountains" is because of excessive logging and grazing. Mencius explained it with the relationship between "raising" and "using": "Well-raised, everything will last forever." If you lose nutrition, nothing will happen without it. The way to balance use and nourishment is "if you don't put too many nets in the pool, fish and turtles won't win food;" It conforms to the principle of ecological balance and can realize the sustainable development of agriculture. Guanzi, Xunzi and Huainanzi all have more detailed discussions and viewpoints than Mencius, which is a profound lesson drawn after natural revenge of deforestation, overfishing and overfishing in some areas. Among them, Xunzi said, "When the vegetation is lush." Catfish, catfish, soft-shelled turtle, loach, silkworm, when pregnant, Wang Yi's poison won't enter the river, won't die, and will never stop growing ... It's time to defile ponds and swamps, so fish and soft-shelled turtle are superior, and the people are more useful. So it's time to cut them down and raise them.
Ecological fragility
Behind the environmental dependence, there is also serious ecological fragility, which is not only manifested in the Yellow River basin in the north, the ecologically fragile mountainous areas in the southwest, but also in the economic center of Jiangnan.
Due to the emergence of "the mountains are exhausted, and the mountains are exhausted", a large number of mountainous areas in southwest China have been reclaimed, and terraces have also appeared in southeast China, and soil erosion is inevitable. In order to alleviate the population pressure, various forms such as cabinet field, paddy field, sand field and coated field appeared in the Song and Yuan Dynasties, all of which used various possibilities to increase the grain planting area and feed more people.
In the south of the Yangtze River, where the national economy depends, polder fields were constantly expanding in the Song and Yuan Dynasties, and the result of competing with water for fields was to destroy the water system, cause floods and frequent disasters. In the Song Dynasty, farmers kept calling for "encircling the lake" and "abandoning farmland". Song Xiaozong once said: "West Zhejiang has its own farmland, that is, there is a flood." In the Southern Song Dynasty, it was repeatedly forbidden to cultivate farmland and cultivate farmland as a lake, but it was impossible because of powerful people.
A more direct description can be seen from folk proverbs, and the visibility and scope are not small. While the above-mentioned "the lake is wide and ripe, and the world is full" is popular, there is also a proverb that "Mianyang Shahu Lake will not be harvested for ten years, and it will be harvested for ten years a year". The fertile land in the plain area is "harvesting for ten years a year", but this economic type is very fragile, and it is often "not harvesting for ten years". because
However, it needs to be pointed out in particular that the development of rice planting has less damage to the environment than wheat planting and millet planting in dry land, and generally will not cause soil erosion. The damage to the ecological environment in the south is mainly dry farming in mountainous areas, especially the damage to the environment in the southwest mountainous areas after the introduction of high-yield crops in the United States. Most areas where rice can be planted are low wetlands, and their own water sources are sufficient. The ability of ecological restoration is very strong, so rice cultivation supported the civilization and progress in the late feudal society of China, which has continued to this day. Its high yield has fed the dense population in the southeast and created a splendid culture. Ina Wenming supported the development of civilization in the later period of the Chinese Empire.
In the south, the embodiment of ecological fragility is completely different from that in the north, mainly in two aspects. One is the soil erosion caused by dry farming instead of rice planting in mountainous areas, mainly in southwest China; Secondly, the reclamation of wetlands in the lake area led to the failure of flood discharge and caused disasters, mainly in the middle and lower reaches of the Yangtze River. So, if the ancient people didn't invent rice cultivation, what would be the history of ecological environment change in China?
Environmental destruction is the mainstream of agricultural history. However, in addition to the main theme of human destruction, there are still some twists and turns to delay the degree of mainstream destruction, that is, there are some positive responses from the ecological point of view. From the point of view of saving land and protecting ecology, many measures have been invented and applied, among which the famous ones are intercropping in the north, "fish farming in rice fields" and "mulberry fish ponds" in the south. These are some measures in the process of technological progress, which have solved the contradiction of insufficient land.
(b) Practices for the protection and sustainable use of land
The practice of sustainable land use is mainly manifested in the following aspects:
1, Intercropping and Intercropping since the Han Dynasty
The planting structure is single, and overpopulation is inevitable in some areas. It is necessary to save land and make full use of it. During the Spring and Autumn Period and the Warring States Period, crop rotation and multiple cropping appeared. There were "four kinds of five harvests" in Guanzi Governing the Country and "one harvest a year" in Xunzi Guo Fu, which was regarded as a pioneering work to improve the land utilization rate in the agricultural history of China. Intercropping and interplanting also began to sprout. [14] During the Ming and Qing Dynasties, intercropping and interplanting became popular, which was related to the shortage of land for immigrants from north to south in the southeast since the Sui and Tang Dynasties. At that time, there were "rice-bean intercropping", "wheat-bean intercropping mixed sowing", "grain-fertilizer intercropping" and "grain-grass mixed cropping".
2. Raising ducks to control locusts in Ming Dynasty.
"Raising ducks to control locusts" is similar to "raising fish in rice fields", which was first seen in the Ming Dynasty. Chen Jinglun in Ming Dynasty recorded the process of raising ducks to prevent insects in detail. Chen Jinglun once introduced sweet potato from Luzon Island to Fujian for trial planting, and later he and his descendants actively devoted themselves to promoting sweet potato planting in various places. Sweet potato has become the food of the general public, which is largely due to Chen Jinglun and their families. It eased the food shortage crisis in southeast China and even many parts of the country at that time. According to scholars' research, raising ducks to control locusts was invented by Chen Jinglun in the process of popularizing sweet potato cultivation. Later, this method really became one of the important methods to control locusts in Jiangnan, and many books on locust control also mentioned this method.
3. "Sangji Fish Pond" in Qing Dynasty
The earliest document of "Mulberry Fish Pond" is recorded in Xinyu, Guangdong Province, which is a unique local agricultural production form in the Pearl River Delta region of Guangdong Province. That is, mulberry fields depend on fish ponds for fertilizer and mud, sericulture depends on mulberry leaves, and fish ponds depend on silkworm excrement and silkworm excrement and other interdependent forms. In the sericulture area of the Pearl River Delta, there is a "mulberry fish pond". This mode of production has continued to this day. According to Gaoming County Records (1894), "Digging deep into the depression, with mud as the foundation on all sides, a pond in the middle, and six ponds with foundations, in which mulberry, livestock and fish are fed, mulberry leaves and silkworm excrement are fed to fish, which is not only beneficial, but also ten times as many crops". That is to say, "Mulberry Fish Pond" organically combines mulberry planting, sericulture and fish culture, forming a virtuous circle in which mulberry, silkworm, fish and mud are interdependent and mutually promoted, avoiding floods in low-lying areas, receiving economic benefits of "doubling crops" and creating an ideal ecological environment. The waste of the former link becomes the nutrient of the latter link (for example, feeding fish with silkworm excrement), realizing comprehensive utilization and reducing environmental pollution.
The above measures can not only ease the tension between man and land, but also protect the ecological environment. The invention of these measures is not only the continuation of China's leading empirical science since the Song Dynasty, but also an effective response to environmental deterioration.
4. "Rice, rice, soup and fish" in the Western Han Dynasty, "fish farming in rice fields" and "rice, fish and duck" since the Eastern Han Dynasty.
"Fish culture in paddy field" is the "interplanting" of planting technology and breeding technology, that is, interplanting rice and fish. It is also a new invention to save land because of the tense relationship between man and land in Jiangnan area. "Fish farming in paddy fields" can be traced back to the tradition of "rice, rice and soup fish" mentioned by Sima Qian in Historical Records of Han Dynasty. However, it is doubtful that the idea of "fish farming in rice fields" began to appear in the Eastern Han Dynasty. [16] However, we believe that it is entirely possible to continue the tradition of "rice, soup and fish" of Vietnamese in the southeast, but there is no corresponding documentary evidence. Mr. You pointed out: "The old farmer in Yongjia mountain area of Zhejiang said that our ancestors began to raise fish in rice fields when Sun Quan ruled the world in the Three Kingdoms. This oral history is in line with historical facts. "
As you said, in ancient times, Shanyue planted rice in mountainous areas, and the flowing water and natural rainfall in the mountains could be guaranteed, but the fish food was limited to a small amount of fish in the mountain stream, which really could not meet the needs. Therefore, I want to breed them in rice fields. After repeated trial breeding and domestication, I finally selected a "field fish" suitable for rice field breeding from carp. Finally, it became today's famous "Oujiang color carp [17]". The existence of "fish farming in rice fields" also needs a key premise, that is, good folk customs. If the fish raised in the rice field are stolen before the owner harvests, then this tradition cannot be maintained.
"Fish culture in paddy field" can be said to be the response and innovation of Shanyue to "rice, rice and soup fish", and it is a three-dimensional "interplanting" in space. Since Ming and Qing Dynasties, due to the tense relationship between man and land, it is another form of interplanting between planting industries, except that one crop of the former was replaced by fish farming. Rice and fish live side by side, planting and breeding are combined, space is used, land is saved, and crop quantity is reduced. People who mainly work in agriculture get some plant foods, which are single in structure and poor in quality. However, "fish farming in paddy field" not only harvested rice, but also obtained protein from animals, which made up for the shortage of animal protein in the food of farming ethnic groups.
"Fish farming in paddy field" organically combines rice planting and fish farming. Fish farming in rice fields has many ecological benefits. When fish feed, it stirs the water in rice field and soil, providing oxygen for rice root growth and promoting rice growth. This kind of fish eats weeds such as grass, tongue grass and cicada in rice fields, which saves the use of pesticides and herbicides. Fish waste is equivalent to applying organic fertilizer to rice fields, and finally people get fish and rice. The protein of animals and plants is complete.
Perhaps for cultural or other reasons, rice has never attracted western consumers in Europe. It is just a multifunctional and cheap substitute or supplement for daily food. It is mainly used to feed homeless groups-soldiers, orphans, sailors, prisoners, the poor and so on. To make up for or replace more delicious food. Rice has other uses. It is often used to feed animals and has many industrial uses, but rice has never been regarded as a daily necessities.
But in China, rice is regarded as flour and rice, at least its contribution is no less than that of wheat. Since it was domesticated and planted about10,000 years ago, rice has been the main food in the eastern world. It not only feeds a large number of people, but also subverts the law that agriculture must destroy the environment in a sense, because planting rice does not necessarily cause soil erosion. Therefore, it supported the continuous development of dense population and feudal society, economy and culture in the south after Ming and Qing Dynasties.
It is precisely because of rice, the only high-yield aquatic food crop, and the use of low wetlands that Chinese civilization will continue in the era after Sui and Tang Dynasties, unlike some civilizations that were interrupted for ecological reasons. Imagine what would happen if China in the East didn't grow rice? Wheat can only be grown in dry land. The output of millet is far less than that of rice. They couldn't feed so many ancient Americans. Corn, potatoes and potatoes were introduced from China in the Ming and Qing Dynasties, but they can't replace rice. Only rice with high yield can keep water and soil. The hero who supported the later development of Chinese civilization was mainly rice. Therefore, we should thank God for giving rice to the people of China. High-yield rice feeds a huge population and relieves the tense relationship between man and land.
The utilization of rice is a great contribution to the development of Chinese civilization. Fish farming in rice fields forms a rice-fish system, which pushes rice civilization to a higher level. At the same time, it also harvested high-quality animal protein, which made up for the vegetarian structure defects formed by single planting structure since Qin and Han dynasties in China. Thirdly, it is a three-dimensional "interplanting" form, which saves land and relieves the tension between man and land for a long time in history; Fourthly, because of the birth of rice and fish, the dependence on pesticides is reduced, the existence of biodiversity is maintained, and the value of weeds living in aquatic environment is enhanced. Biodiversity is a scarce product of our time, which can restrain the negative effects of chemistry and petroleum agriculture and help us achieve the goal of harmonious coexistence between man and nature.
6. "Fish farming in paddy field" and "Duck farming in paddy field" and their modern significance.
Although rice cultivation has no aggravating effect from the perspective of soil and water conservation, rice cultivation, even terraced fields, will not cause soil erosion. Reclaiming paddy fields in the south only occupies geometric space when floods come, so it is impossible to discharge floods, resulting in floods. When chemical fertilizers and pesticides are not used in large quantities, it will not cause water pollution. However, today, due to the extensive use of chemical fertilizers and pesticides, the rice field ecosystem has been destroyed, and the harmful substances in the soil in arid areas are only.