Basic characteristics and characteristics of the historical evolution of man-land relations in Ningxia

The increasingly serious environmental problems in the middle reaches of the Yangtze River are the result of the long-term accumulation of tensions between humans and the environment. If the evolution of the specific form and connotation of the conflict and confrontation between man and nature is taken as the main clue, the evolution of the relationship between man and land in the middle reaches of the Yangtze River in historical periods can be divided into three stages.

The first stage roughly lasted from about 10,000 years ago to the end of the Eastern Han Dynasty (early 3rd century AD), that is, the early stage of agricultural society. At this stage, the relationship between man and land in this area is mainly manifested in the harsh living environment, hard life, human reverence for nature and partial destruction of the natural environment.

In the early agricultural era, human life in this region was very difficult: material scarcity, a very fragile economic system, and extremely vulnerable to natural disasters, which even led to the decline of regional civilization. The key lies in the fact that human beings are very weak in resisting natural disasters, and this region is an area prone to frequent and serious flood disasters. During the flood period between 5800 and 5500 years ago, the Daxi culture in the hinterland of the Jianghan Plain suffered a devastating blow; between 5000 and 4800 years ago, the floods severely damaged the Qujialing culture. Humans living in such an environment have more psychological reverence for nature than a sense of closeness and harmony. Even with the successive use of bronze and iron farm tools, the basic pattern of the relationship between man and land in this region has not fundamentally changed. From the Shang, Zhou, Spring and Autumn and Warring States periods to the Han Dynasty, this area has always been famous for its "vast land and sparsely populated area" and "fire farming and water plowing". The harsh living environment and living conditions and the resulting human reverence for nature are still the reason. The mainstream of human-land relations during this period. The core problem is that humans basically do not have the ability to withstand floods. From the Spring and Autumn Period and the Warring States Period to the Han and Jin Dynasties, the Lianghu Plain and the Poyang Plain were mainly landscapes with interlaced rivers and lakes and dense lakes and swamps. Whenever a flood came, the Yangtze River's tributaries and its tributaries would flood, creating a vast expanse of water. After the flood receded, fevers would become prevalent. Such a natural environment is naturally not the most suitable place for human production and life. In the early days of agricultural society, the popular farming method of "fire farming and water plowing" in this area caused a certain degree of damage to the natural environment of the area. The damage caused by "mountain logging" activities was even greater, just because of the "land "It's vast but sparsely populated." These damages are still localized. The second stage spans from the late Han Dynasty and the Three Kingdoms to the middle of the Ming Dynasty (the mid-15th century AD). At this stage, the basic characteristics of the relationship between man and land in this area are: with the increase in population and the advancement of productivity, the amount and ability of human beings to claim the natural world is increasing day by day, and the ability of human beings to resist nature and utilize nature is gradually increasing, and the demand for nature is gradually increasing. The awe of people has decreased; at the same time, the impact and intervention on nature is gradually increasing. During this period of more than a thousand years, the area's population and socio-economic development have experienced ups and downs, and natural environmental factors such as climate, rivers, lakes, and mountains and forests have also shown complex changes under the influence of the dual factors of natural laws and human activities. evolution process. For example, in terms of population, although there have been twists and turns, from the Sui, Tang and Song dynasties to the Yuan and Ming dynasties, the peak population of this region has been increasing. In some areas, there has even been a phenomenon of "narrow land and dense people". But overall, the population has increased. The contradiction between the local areas is not very prominent. The increase in population has provided labor resources and promoted the progress of productivity, thus causing some changes in the relationship between man and land in this region. This is mainly reflected in three aspects: First, rice agriculture has gradually broken through the level of "fire farming and water plowing". Pitang irrigation technology has been greatly developed. The continuous cropping system has gradually replaced the abandonment farming system and developed towards the multiple cropping system. Advances in farming systems and technologies have increased the level of intensification, increased output per unit area, and enabled agricultural production to develop in the direction of intensive farming, thereby increasing the utilization rate of land resources and reducing the damage to the natural environment at the same population level. Second, embankments on rivers and lakes were gradually built, and farmland began to rise. From the late Han and Six Dynasties to the late Tang and Five Dynasties to the Song and Yuan Dynasties, some embankments were built intermittently on both sides of the Jingjiang River, the Han, Xiang, Yuan, and Gan rivers, and around Dongting Lake and Poyang Lake. By the middle and late Southern Song Dynasty, polders and field fields had sprung up in the Poyang Plain and the Lianghu Plain, thus solving the technical obstacles to the development of plain lake areas. However, these river embankments are only intermittently connected and have not yet formed a line; there are still many water diversion holes in the Jingjiang River and the lower reaches of Han, Hunan, Yuan and Jiangxi. During the flood period, floods often divert through the holes and the rivers are silted up. The intensification of pad and flood disasters is not yet serious; the development of polders and barrens in plain lake areas is still in its infancy, and a large number of water storage areas still exist. Therefore, the original river-lake relationship in the plain lake area basically maintains a relatively balanced state. The third is the development of terraces in hilly and low-mountain areas. Although the development of terraces destroys the original vegetation in hilly and low-mountain areas, it is a more advanced land use method because terraces can retain hillside water layer by layer and prevent soil from being washed away. However, during this period, slash-and-burn farming was prevalent in most of the low hills and hilly areas in this region. This extensive farming method has caused great damage to the forest vegetation in the area. However, these farmlands are mainly concentrated in low mountainous and hilly areas, and their impact on the ecological environment does not affect the overall situation. The third stage extends from the mid-Ming Dynasty to the Republic of China (and even to the present day).

Marked by the gradual formation of the embankment systems of the Yangtze River, Han Dynasty, Dongting Lake, and Poyang Lake, the high-level development of the farmland economy in the plain lake area, and the comprehensive development of the mountainous areas in the middle and upper reaches, the relationship between man and land in this area has gradually entered a state of comprehensive tension, mainly manifested in the human The activities began to cause comprehensive damage to the natural environment of the area and the revenge of nature on humans continued to intensify. The average annual population growth rate in this region during the Ming Dynasty was approximately 4.2 (per thousand), which was roughly the same as the national average growth rate. Although the social unrest in the Ming and Qing Dynasties caused a significant decline in the population of this area, after the "San Francisco Rebellion" was put down, the population of this area continued to grow, and soon exceeded the peak population of the Ming Dynasty (35.734 million), reaching 54.706 million in 1776. In 1850 it reached 77.048 million. Since the population growth rate was much faster than the growth rate of cultivated land, the contradiction between man and land became increasingly acute, and the per capita cultivated land area continued to decline. By the 25th year of Jiaqing (1820), the recorded per capita cultivated land dropped to less than 2 acres. Although this situation was alleviated in the late Qing Dynasty due to the population decline in the area caused by the Taiping Rebellion, it did not fundamentally change. Population growth not only provides abundant human resources for economic development in plains and mountainous areas, but is also an intrinsic driving force for embankment construction, field development, and diversified utilization of mountainous resources. It was against this background that from the period of Jiajing and Longqing in the mid-late Ming Dynasty to the mid-Qianlong period of the Qing Dynasty, the embankments on both sides of the middle reaches of the Yangtze River, the lower reaches of the Han River and other important tributaries gradually became a line, and most of the holes were blocked one after another, and the periodic flooding of floods gradually was brought under control; the two lakes plains also entered a period of comprehensive development. Although the development of its farmland economy was repeated during the Ming and Qing Dynasties, it still reached a climax in the middle of the Qing Dynasty and continued to develop, forming a vicious expansion; while in western Hunan and Hubei , southern Shaanxi, southern Hunan and other surrounding mountainous areas also experienced a development climax during the Qianlong period. Large-scale development has brought social and economic prosperity to the region, but it has also caused the deterioration of the ecological environment and intensified the tension between man and land. This is mainly manifested in three aspects in plain lake areas: (1) hanging rivers and river meanders are highly developed; (2) rivers and lakes are silted and the water system is disordered; (3) floods are becoming more and more frequent, and their degree of damage and affected area are also becoming more and more frequent. It has become a major obstacle to the socio-economic development of the region. In mountainous areas, the tension between man and land is mainly manifested in the following: (1) Forest resources and related biological resources are destroyed, and the disappearance of forests and the expansion of agricultural reclamation areas proceed at an alarming rate; (2) Water and soil erosion become increasingly serious , agricultural land resources are increasingly depleted; (3) climate changes in mountainous areas are abnormal, floods and droughts are more frequent, and some unprecedented droughts and floods have occurred. The deterioration of the natural environment, especially the intensification of floods and droughts, directly affected the socio-economic development of the region. From the late Qing Dynasty to the Republic of China, the region's socio-economic development was slow or even stagnant for a long time. 2

In the evolution of the relationship between man and land in this area during the historical period, population has always been the most active factor in the relationship between man and land. The growth of population is an important opportunity to trigger the upsurge of development in this area, and it is also an important factor in the development of this area. The fundamental factor in the evolution of the relationship between man and land; resource utilization methods (especially land use methods) are a concentrated expression of the relationship between man and land, and are also the central link in the evolution of the relationship between man and land; while the evolution of rivers and lakes and vegetation changes are the most important factors in the natural environment. Active factors are deeply affected by human activities. They are the result of the simultaneous interaction of natural evolution and human activities, and have a great impact on human survival and development. The frequency and intensification of drought and flood disasters are caused by human activities. A concrete manifestation of the deterioration of regional relations. Therefore, population changes, evolution of resource utilization methods, changes in rivers, lakes and vegetation, and intensification of natural disasters are the four most important factors in the relationship between man and land in this region and its evolution. (1) The evolution of population size and structure and the relationship between man and land. On the one hand, for thousands of years from the origin of agriculture to the end of the Han Dynasty, due to the harsh living environment and difficult life in this area, the population was relatively sparse. The tense relationship between man and land was mainly manifested in human beings' reverence for nature. Similarly, in the late Tang and Northern Song dynasties when economic and technical conditions were basically in place, the main reason why the Lianghu Plain was not developed was also due to the lack of labor. On the other hand, the needs of human survival and development are the fundamental motivation for the gradual development of resources in this region and the continuous development of social economy. Although the expansion of farming areas, the emergence and development of artificial embankments, and the destruction of forest vegetation in mountainous areas have greatly changed the natural geography and natural ecosystem of this area, it is also a means and method for humans to fight against nature for survival and development. result. Of course, continued population growth is also one of the sources of continued tension between man and land in this region since the Ming and Qing Dynasties. During the Ming and Qing Dynasties, the fundamental reason why people continued to move to the flood-prone lake areas and mountainous areas where tigers and wolves were infested was the increasingly serious population pressure; migration to uncultivated lake areas and mountainous areas became one of the most important ways to alleviate population pressure. one. After immigrants entered the lake area and mountainous areas, large-scale reclamation and other economic development activities prompted rapid changes in the original relationship between man and land, exacerbating the tension in the relationship between man and land in the region. (2) The evolution of resource utilization methods, especially land use methods, and the evolution of the relationship between man and land. In the process of increasingly tense relationships between man and land in this region after the mid-Ming Dynasty, population growth was a key factor; however, at least in theory, population growth does not necessarily lead to tense relationships between man and land and the deterioration of the ecological environment. The evolution of resources, especially land resource utilization, is a key link in the tense relationship between man and land. In the development process of the mountainous areas in this area, primitive and extensive reclamation methods are the fundamental cause of ecological deterioration, and the increase in population is only a driving force.

The relationship between man and land in most plain areas of this region is mainly characterized by the interdependence and contradictory relationship between man and water. The rise and fall of water conservancy projects is the most critical factor in the human-land relationship system in plain areas. The rise and fall of water conservancy also affects the specific manifestations of the relationship between man and land: in the Nanyang Basin, the widespread construction of farmland water conservancy has developed rice agriculture in this area, while the failure of farmland water conservancy has led to a substantial reduction in rice planting area and The increase in dry farming area; in the two lakes plain, the rise of farmland has brought about the comprehensive development of the plain lake area, but its excessive development and irrational use have caused damage to the ecological environment, and ultimately brought negative consequences to human survival and development. as a result of. This is not only reflected in the above-mentioned disordered river and lake systems and intensified waterlogging disasters, but also in the simplification of land use methods: Accompanying the great development of the farmland economy is the unilateral development of planting agriculture, which changes the agricultural economic structure. The use of land resources has become increasingly univocal, exacerbating the tension between man and land in the plain lake area. (3) The evolution of rivers and lakes, vegetation changes and the evolution of the relationship between man and land. The evolution of rivers and lakes is an important benchmark for the evolution of man-land relationships in plain lake areas. However, the evolution of rivers and lakes is the result of the simultaneous interaction of very complex natural evolution and human activities. It cannot simply correspond to the evolution of rivers and lakes and the evolution of the relationship between man and land. In particular, it is not appropriate to simply associate the changes in lakes in some areas with human activities. environmental degradation caused by the activities. Take the evolution of the Jianghan Lake Group as an example: the formation of the embankment systems of the Jingjiang River, the Han River and their important tributaries played a crucial and arguably decisive role in the development, expansion and decline of the Jianghan Lake Group; but it is believed that the embankments The construction of lakes does not necessarily lead to the shrinkage of lake area, and the relationship between the two should be further explored in depth and detail. Changes in vegetation, especially forest area, are an important criterion for measuring the relationship between man and land in hills and mountainous areas. Different from the evolution of rivers and lakes, the destruction of vegetation is basically the unilateral result of human activities. Therefore, the destruction of vegetation in the hills and mountains of this area is manifested by advancing from hills to low mountains, middle mountains, and medium to high mountains, that is, from the edge of the mountainous areas to the hinterland. process, and this process is consistent with the economic development process of the region. The direct consequence of the destruction of forest vegetation is the gradual increase in water and soil erosion, while the indirect consequence is abnormal climate change and the loss of floods and droughts. In addition, large amounts of sediment are released, exacerbating the siltation of downstream river beds and the obstruction of rivers and lakes. (4) The intensification of natural disasters and the evolution of the relationship between man and land. After the mid-Ming Dynasty, the frequency and intensity of disasters in this area continued to increase. Although there were natural reasons, the main reason was the negative effects of human activities. In fact, most floods and droughts that have had a significant impact on the region's social economy since the Ming and Qing Dynasties are closely related to human activities. Other disasters, such as flash floods and mudslides, are directly caused by unreasonable human activities. It can be classified into the category of "man-made natural disasters". Disasters and their impact on social and economic development are highly regional. In this region, floods are frequent disasters in the plain lake area and the middle and lower river valleys of the Han, Xiang, Yuan, and Gan tributaries. Droughts mainly occur in the upper reaches of the Han River in the north of the region and in the hills and low mountains around the plains. Loss and subsequent flash floods and climate anomalies are the most important disaster forms in the Qinba Mountains, western Hunan and Hubei, northeastern Hubei, and Hunan and Jiangxi mountains. As far as the impact of drought and flood disasters is concerned, generally speaking, drought has a wide range of impact and lasts for a long time. The so-called "flood is in one line, drought is in a large area", which has a more severe impact on the local economy; although the damage of flood disasters is often It is devastating, but the scope is small and the time is short. The disaster-stricken areas have strong self-rescue capabilities and the economy recovers quickly. Because of this, although there were frequent floods in the two lakes plains during the Ming and Qing Dynasties, especially in the late Qing Dynasty, they did not cause a comprehensive economic recession and were still able to maintain an advanced position in the region. However, the deterioration of the ecological environment in the Qinba Mountains and floods and droughts, especially droughts, The intensification has led to the overall decline of social economy.