Chapter 19 Section 2 Ecological Changes

The natural world is a rich food bank for human beings, but there is only one earth, and the land area is also limited.Although China has a vast land and abundant resources, it has a large population, and the contradiction between agricultural development and ecological imbalance has become more and more serious in the past thousand years.It was not until the founding of the People's Republic of China that this contradiction began to be gradually resolved.But there is still a long way to go to straighten out the relationship between agricultural production and ecological balance. The Yellow River Basin was the first area in China to be developed and the first dawn of civilization to emerge. Until the Yin and Zhou dynasties, most of the areas along the river were still lush and green.The hunting area of ​​the Yin and Zhou royal families is in the Central Plains. Every time the Yin king hunts large-scale fields, he hunts dozens of wild animals, the most of which are "moose", that is, four elephant deer, and others such as rhinoceros and elephant. Tigers, tigers, leopards, bears, deer, roe deer, monkeys, wild boars, etc., are frequent prey.According to oracle bone inscriptions, King Wuding of Yin once hunted more than 350 Sibuxiang deer, 71 rhinos and a large number of other wild animals. "Yu Zhou Shu" records that after King Wu destroyed Yin, he hunted on a large scale for the first time. He actually hunted more than 5,000 elephant deer, 12 rhinos, and countless tigers, leopards, bears, raccoon dogs, deer, yaks, etc.Until the Han Dynasty, the Jianghan River Basin was still forested and grassy, ​​just like the present Greater and Lesser Khingan Mountains, where many wild animals haunted it.In the future, with the increase of population and unrestrained agricultural development, the natural ecology will gradually lose its balance. Every step forward in the agricultural area, the natural food bank will shrink by a step.Before the Han Dynasty, there was still room for maneuver in agricultural development. This contradiction was not obvious. After the Han Dynasty, the natural food bank shrank intensified. The south retreated.In the Tang Dynasty, the Three Gorges "could not hold back the sound of apes on both sides of the strait"; in the Song Dynasty, there were still a large number of wild elephants in Lingnan.In recent centuries, except for apes in Xiangxi in the Three Gorges, Leshan in Sichuan, Lingshui in Hainan, Xishuangbanna in Yunnan, and parts of Guangxi, most of the other beasts mentioned above have long been extinct in the large areas south of the Yangtze River.It can be seen that for more than 1,000 years, due to the random reclamation of farmland and out-of-control deforestation, beasts and birds have been retreating, retreating to the Xing'an Mountains in the north, Qinghai Lake and Minshan in the northwest, retreating to Shennongjia in the Central Plains, and retreating to Wuyi Mountain and Mount Wuyi in the south. Hainan Island and Xishuangbanna, China's natural food bank, are the only green islands left. Some animals have become extinct, and some are on the verge of extinction. The remaining rhinoceros and wild elephants are only the habitat of the 3 million mu of virgin forest in Xishuangbanna. landed.In ancient times, the Sibuxiang deer, which was as numerous as a cow's hair, was originally a native animal in my country. It was extinct in the late Qing Dynasty, and it was only extradited from Britain in recent years.Of course, China has developed a large-scale agriculture and breeding industry, feeding the largest population in the world, and history has recorded the great achievements of our ancestors in conquering nature.The earliest ecological theory in the world is also found in Chinese historical records. Some ancient politicians and thinkers, such as Zhou Gong, Guan Zhong, Meng Ke, Xun Kuang, etc., have left glorious chapters in maintaining ecological balance.However, the ecological imbalance of nearly 1,000 years has left us with a heavy historical burden.

In addition to the shrinking of the natural food bank, some of the developed production bases in my country have degraded and even been swallowed by flying sand or yellow water, mainly in the northwest and yellow flood areas.During the Han and Tang dynasties, China's political center was in the Guanzhong Plain. During that time, the Silk Road was unimpeded and the Northwest region was full of vitality.In the prosperous Tang Dynasty, from the Hexi Corridor to the Gaochang area in the Tarim Basin, there were still "sangmayiye", "real estate and five grains", and "wheat and grains were cooked again" (see "New Tang Book" and "Song History·Gaochang Biography" ).However, after the political and economic center moved southward, the production and ecology of the entire northwest region were out of balance for a long time. Trees were felled, vegetation was destroyed, water and soil were lost, and the desert moved southward. Over the past few centuries, the ancient city of Gaochang has been submerged by sand dunes.

The Yellow River nurtured the ancient civilization of the Chinese nation, but also brought countless disasters to history.Over the past 2,000 years, there have been 1,500 recorded cases of the Yellow River overflowing, with an average of one flood in less than two years, and the downstream has been diverted many times.In addition to natural embankment breaches, there are also man-made embankment breaches. There are records of man-made embankment breaches, and the losses are very heavy. The earliest record can be found in "Historical Records·Wei Family". During Kaifeng), the Yellow River flooded the city, forcing the king of Wei to surrender, and the whole city of Kaifeng suddenly became a state of Ze, with corpses everywhere. After nearly a century, Sima moved to Daliang for inspection, but what he saw was still ruins.At the end of the Tang Dynasty, Zhu Wenjian, a warlord of the Five Dynasties, dug up the embankment of the Yellow River three times in order to prevent Li Keyong's cavalry from going south, causing severe floods in Henan and Shandong for many years, and countless losses. In the 1180s, in order to resist the Song army, Xixia broke the Yellow River embankment in Lingzhou and flooded the Song camp. Of the 87,000 middle route troops in the Song Dynasty, 74,000 people were drowned, and countless people were drowned (see "Song History Xixia pass").Ming history records that in the 15th year of Chongzhen (AD 1642), in order to intercept Li Zicheng's peasant army, the Ming Dynasty broke the Yellow River embankment in Zhujiazhai, and the flood rushed straight into Kaifeng, drowning 340,000 people.From these historical situations, it can be seen that for two thousand years, people's life, property and agricultural production in the Yellow River Flooding Area have often been seriously damaged.

For a long time, the Loess Plateau has been indiscriminately deforested, the distribution of agriculture, forestry, and animal husbandry is out of balance, and a large amount of water and soil have been lost. The large swaths of fertile soil opened up in the era of the well field system have become ravines where no grass grows, and the arable ground soil layer has been seriously washed out. It is estimated that the entire Loess Plateau loses about 1.6 billion tons of soil and 30 million tons of nitrogen, phosphorus, potassium and organic fertilizers every year.The average sediment concentration of the Yellow River is 37.5 kilograms per cubic meter, ranking first among the major rivers in the world.The riverbed in the middle and lower reaches is three to ten meters above the ground, turning into a "hanging river".It was not until after the founding of the People's Republic of China that it began to be fundamentally and gradually rectified. In the past 40 years, there has been no breach of the embankment. However, there is still a lot of work to be done to completely control the Yellow River and make the planting and breeding industries on the Loess Plateau develop in harmony with the ecological cycle.