Was there a plague of locusts in the Tang Dynasty?

Yes, the following are related documents.

Locust plague is a kind of disaster that has great influence on agricultural society. According to the statistics of the new and old Tang books and Tang and Five Dynasties meetings, there were 45 locust plagues in 340 years from Tang to Five Dynasties, with an average of about 7.6 years. These factors include the occurrence of multiple locust plagues in the same year and the duration of locust plagues for up to two years. If the number of locust plagues in that year is counted as one year, and the disasters that span two years are counted as two years, then, according to the year, locust plagues occurred in 42 years, accounting for about 12% of the whole year, with an average outbreak of about once every eight years. According to Deng Yunte's History of Famine in China, the average locust plague occurred every 8.8 years in Qin and Han Dynasties, with 3.5 years in Song Dynasty, 1.6 years in Yuan Dynasty and 2.8 years in Ming and Qing Dynasties. In contrast, the plague of locusts in the Tang and Five Dynasties was not very serious, but it was difficult to accurately grasp the actual year of the plague of locusts in the Tang and Five Dynasties because of the incompleteness and fuzziness of the materials. For example, it is recorded in history that "the drought locust in Dali prefecture is still old" 1, and "still old" means continuous years, but the specific years are unknown.

In the past, people had a clear understanding of the accompanying situation of locust plague and drought, which was clearly reflected in the historical materials of the Tang Dynasty. Such as: "In June of the second year of Zhenguan (628), drought locust in Gyeonggi" 2; "In April of the first year of Xingyuan (784), since the spring drought, wheat has died, grain has no seedlings, and there is a locust plague in Guanzhong" 3; "In June of four years (839), there was a great drought, and locusts ate fields" 4 and so on. However, the great influence of flood on locust plague is often ignored. When investigating the floods in the Yellow River and Yangtze River basins, the author noticed that there were some internal relations between locust plague and floods. Next, the author wants to take the locust plague in the Tang and Five Dynasties as the main object, and try to discuss the chain relationship between locust plague and flood.

As far as the area where the locust plague occurred in the Tang Dynasty is concerned, according to the administrative division of the 15th Road in Kaiyuan, if the locust plague occurred on different roads in the same year is counted once each, we can know that there are four times in Guannei Road, eight times in Gyeonggi Road, eight times in Henan Road, eight times in Duji Road, five times in Hedong Road, 14 times in Hebei Road and 1 time in Longyou Road. It can be seen that there are 55 occurrences in the north and 13 occurrences in the south, and the frequency of locust occurrence in the north is obviously higher than that in the south. According to the current administrative divisions, the northern locust areas are mainly in Shaanxi, Shanxi, Hebei, Henan and Shandong provinces, and generally belong to the middle and lower reaches of the Yellow River. The south mainly occurs in Zhejiang, Fujian, Sichuan, Hubei, Jiangxi and other provinces, mainly distributed in the middle and upper reaches of the Yangtze River. The reason why these areas are prone to locust disasters is not only determined by local climate, topography, soil, vegetation and other factors, but also closely related to local flood disasters.

According to biologists' research, there are three kinds of locusts in China, namely Asian migratory locust, Tibetan migratory locust and East Asian migratory locust. As the name implies, the Tibetan migratory locust is distributed in Tibet, the Asian migratory locust is distributed in Xinjiang, Qinghai, Gansu and Inner Mongolia, and the East Asian migratory locust is distributed in other areas. Therefore, the locust disaster reflected by relevant historical materials should be the disaster of oriental migratory locust.

The reproduction and development of Locusta migratoria manilensis require that the daily average temperature be above 25℃ for more than 35 days. In winter, if the daily average temperature is lower than-10℃ for more than 20 days, or lower than-15℃ for more than 5 days, the eggs can't overwinter safely. The temperature was warmer in Sui, Tang, Five Dynasties and early Song Dynasty. In his masterpiece "A Preliminary Study on Climate Change in China in the Last Five Thousand Years", Mr. Zhu Kezhen designated this period as the third warm period in the history of China. According to the results of citrus reticulata in Tang Palace recorded in Youyang Miscellaneous Notes and Li Deyu's Ruiju Fu, it was proved that the temperature in winter was generally not lower than -8℃ at that time, because citrus reticulata could only resist it-therefore, it could completely meet the temperature requirements of locust eggs during the Sui, Tang and Five Dynasties.

It generally takes 60 to 200 days for locusts to develop into adults from eggs to larvae, which is called a life cycle or generation, or generation for short. Most migratory locusts mature in summer and autumn, with summer locusts as the first generation and autumn locusts as the second generation. The famine in the third year of Zhenguan (629) is a typical locust plague in summer and autumn. "Xuzhou locust" in May this year; "Autumn, Dedaikuo and other state locusts". Generally speaking, one or two generations can occur in a year, sometimes even three or four generations, so there are also cases of spring locusts and winter locusts. According to the data collected by the author, it is clear that there are 35 times of locust plague in season or month, including 3 times in spring, 6 times in summer/kloc-0, 5 times in autumn/kloc-0 and 0 times in winter. Summer and autumn are as many as 3 1 time, accounting for 60% of the total number of locust disasters from Tang Dynasty to Five Dynasties. Summer and autumn are the periods of frequent floods and droughts in East Asia, which are extremely beneficial to locust reproduction.

Locusts like to eat reeds, barnyard grass, white grass, dog tooth grass and Artemisia plants, in addition to shrimp grass and Salicornia bigelovii Torr mixed in coastal areas. Therefore, the areas suitable for the propagation and development of Locusta migratoria manilensis are generally distributed in plains, river valleys and low-lying areas along seashores and lakes below 200 meters above sea level. Ma Shijun and others divided the distribution area of Locusta migratoria manilensis in China into four categories, namely flood locust area, coastal locust area, lakeside locust area and waterlogged locust area. From the names of these four locust areas, we can easily find the close relationship between the growth and reproduction of locusts and soil water content. In fact, studies have proved that the incubation of locust eggs requires the soil water content to be kept between 8% and 22%. Adults of locusts naturally like high temperature and drought, but the growth of larvae must have a relatively humid environment. So after the flood, those flooded areas often become suitable areas for larvae. The most suitable condition is drought after flood, which ensures both temperature and humidity.

Biologically, the occurrence areas of migratory locusts are divided into three categories: 1. The place of occurrence, also known as the perennial place, has the best breeding environment for locusts, and spreads and migrates outward when the locust plague breaks out on a large scale; 2. The general occurrence area, also known as the suitable area, has the conditions suitable for the breeding of migratory locusts; 3. The temporary occurrence area of locusts is also called the spreading area or invasion area of locusts. The meaning and scope of locust area mainly refers to the occurrence base and the area suitable for living, but our folk custom also includes the temporary occurrence place.

Second, the situation of locust plague in the Yellow River Basin

The flood locust area mainly refers to the beaches and wasteland on both sides of the river. As far as the flood and locust disaster areas in the Yellow River basin in Tang Dynasty are concerned, they mainly include yu zhou, Bozhou and Dezhou in Hebei Province (now Daming in Hebei Province, Liaocheng and Dezhou in Shandong Province) located along the middle and lower reaches of the Yellow River. Henan Road, Slippery State, Zhou Pu and qi zhou (i.e. Puyang, Henan, southern Huimin, Shandong); Henan, Shaanxi, Guo and Duji provinces Zhengzhou (now Luoyang, Sanmenxia and Zhengzhou in Henan). Among them, Shaanxi, Slip, Wei, Qi and Bo were the key areas where the middle and lower reaches of the Yellow River flooded in the Tang Dynasty. In addition, in Duji province, tributaries of the Yellow River such as Yi, Luo and Gu near Luoyang sometimes overflow. Therefore, it is not surprising that this area has become the most serious locust plague area in northern China. According to records, there was a locust plague in 10, accounting for 23.8% of the total number of years of locust plague in China. Followed by Jingzhaofu, Tongzhou, Huazhou, qi zhou, Longzhou and other places along the Weihe River in Guanzhong (that is, Xi 'an, Weinan, Baoji and other areas in Shaanxi today), the locust plague occurred in this area for 8 years, accounting for 19% of the total number of years of locust plague in this period. These areas were important places where two large-scale locust plagues occurred in the Tang Dynasty. The first time was from the first year of Kaiyuan in Tang Wenzong (836) to the fifth year of Kaiyuan (840), covering Youzhou, northern Zhou Zhen (now northern and western Hebei), southern Chen Zhou (now Zhoukou in Henan), Hezhou, western Shanbi (now Yuncheng in Shanxi and Sanmenxia in Henan) and eastern seas. The second time was from three years in Xian Tong, Tang Yizong (862) to ten years in Xian Tong (869). This time, the disasters in Du Dong and Shanbi lasted for quite a long time, which can basically be regarded as the occurrence base, extending westward to Gyeonggi and its two neighboring states (Xi 'an and Weinan in Shaanxi) and southward to Huainan.

In addition to the above two areas, Hezhongfu (Zhou Pu) and Luze Jiangze (now Yuncheng, Linfen, Jincheng, Changzhi and other areas in Shanxi) located in the south of Hedong Road also belong to the type of waterlogging locust area. This area is just in a triangle with Tongguan as the apex, Shanxi-Shaanxi Yellow River and Shanxi-Henan Yellow River on both sides, bordering Gyeonggi Province in the west and the waterlogged locust area of Duji River in the south.

Generally speaking, after the spring flood, summer locusts are likely to occur in counties on both sides of the main tributaries in summer. If a river disaster occurs in the autumn of the previous year, it will also lead to locust outbreaks in the spring and summer of the following year. If the river overflows in summer, the possibility of autumn locusts will be higher. Here are two examples to prove the relationship between river disasters and locust disasters. First, in the summer of the third year of Tang Kaicheng (838), "The river broke, invaded Zheng and slipped out of the city" 7. In the autumn of that year, a large area of locusts broke out in Henan and Hebei. Secondly, in the sixth year of Tianfu in the Five Dynasties (94 1), "In September, Huazhou broke the river and all flowed eastward ... Yanzhou and Zhou Pu were drowned." In April of the following year, crops in Shandong, Henan and Kansai counties were hit by locusts. 10

The waterlogged locust areas are mostly low-lying areas, which are easy to accumulate water. The largest and most typical waterlogging locust area in China is that in southwest Shandong, which is equivalent to Cao Zhou, Yunzhou, northern Songzhou and southern Yanzhou in Tang Dynasty. Because this area is close to the river, the flood of the Yellow River often affects this area and even forms waterlogging. For example, in April (932), the third year of Changxing in the Tang Dynasty after the Five Dynasties, "Yunzhou said that the Yellow River overflowed its banks, with a width of 30 miles, and flowed eastward (eastward flowing into Yanzhou boundary)." 1 1 In June of the first year of the late Jin Dynasty (944), "Huazhou River was decided, Mian, Cao and Dan (Danzhou was set up at the end of the Tang Dynasty, about in the southeast, southwest of Yanzhou and northeast of Songzhou), and Pu and Yun were surrounded by Liangshan and Songzhou." 12 is the breach of this river, which made Juye Ze, which was originally in the south of Liangshan, expand in a large area due to yellow water irrigation, and incorporated Liangshan into the lake, forming the later famous Liangshan Lake. It can be said that this is the biggest flood disaster in Tang and Five Dynasties. From another point of view, it also has the nature of lakeside locust area. Therefore, the locust situation in this area is more serious. For example, in July (948) of the first year of Ganyou in the later Han Dynasty, states such as Yun and Cao all talked about their lives 13. In May of the following year, Yanzhou, Yunzhou and other states "played hard" again. 14 "slug" is a wingless larva of locust.

Third, the situation of locusts in the Yangtze River basin.

First of all, there are few historical materials of locust plague in the whole southern region during the Tang and Five Dynasties. A * * * only records eight years of disasters. Therefore, as far as the Yangtze River Basin is concerned, relevant information is even more scarce. Among them, the areas that can be determined are: Quzhou (now Daxian County, Sichuan Province); Deng, Tang, Jing and Xiang on Shannan East Road (now Nanyang and Biyang in Henan, Jingzhou and Xiangyang in Hubei); Hongzhou (now Nanchang City, Jiangxi Province) is on Jiangnan West Road. According to the number of times, it is four.

According to historical data, the types of locust areas in the Yangtze River basin are mainly river waterlogging locust areas and lakeside locust areas, and there are no typical examples in waterlogging locust areas.

Jiangyan locust area mainly includes Quzhou in Bashui Basin, a tributary of the Yangtze River. Deng, Tang, Xiang and other States are in the Hanshui River Basin and the Yangtze River Basin near Jingzhou. For example, in July of the first year of Huichang (84 1), "there are floods in the south of the Yangtze River, rotten rivers in the Hanshui River, and many houses in the equal state". Shortly after 15, "Zhou Huang Deng and Tang are equal to Shannan". 16 Dengzhouhe borders Xiang and County and is very close to the main stream of Hanshui River.

The lakeside locust areas are mainly Jiangzhou and Hongzhou around Poyang Lake, where a large area of locust plague broke out. For example, in the autumn of the third year of Changqing in Mu Zong (823), there was a "locust plague of 80,000 hectares" in Hongzhou. 17

As can be seen from the locust plague areas mentioned above, the locust plague in the middle reaches of the Yangtze River basin is more serious, which coincides with the flood-prone areas in the Yangtze River basin during this period. The author thinks that this situation is by no means accidental, and the internal relationship between flood and locust plague can not be ignored.