Please help with information on the Arbor Day blackboard poster! Thanks! (*^__^*)

Care for vegetation and green the motherland

The Yellow River is the cradle of Chinese civilization and is respectfully called the mother river by descendants of Yan and Huang. However, such a mother river has been in trouble in recent years, and some people have even raised questions about what the mother river has brought us. Let's look at this set of figures: In 1841, the Yellow River broke through Xiangfu, Henan, flooding 23 counties in Henan and Anhui provinces, and the water surrounded Kaifeng City. Floods caused disasters in parts of the middle and lower reaches of the Yangtze River in Hunan, Hubei, Jiangxi, Anhui and other provinces. In 1843, there was a huge flood in the middle reaches of the Yellow River. The peak flow rate in Shaanxi County was 36,000m3/s, and 27 prefectures and counties in Henan and Anhui provinces were flooded. Local floods occurred in Hebei, Shandong, Sichuan, Jiangxi, Guangdong and other provinces. In 1884, the Yellow River burst into Shandong 38 times, with more than a million victims and more than a thousand casualties in Qihe County alone. This is only a small part. Faced with such a series of disasters, it is reasonable to ask questions. However, the occurrence of these disasters is ultimately our own fault!

The Yellow River imports 1.6 billion tons of sediment to the lower reaches every year. If the mud and sand were built into a long embankment of one meter high and one meter wide, its length would be three times the distance between the earth and the moon, and it could circle the equator 27 times. A large amount of sediment blocked the river channel, causing the Yellow River to burst many times. Where does so much silt come from? Simulated rainfall experiments show that the average soil infiltration rate and stable infiltration rate under annual vegetation cover are greater than those under perennial vegetation; the amount of soil loss under perennial grassland vegetation is significantly less than that of annual vegetation; for grassland vegetation types at the same stage, the soil loss increases with time. With the increase in vegetation coverage, the stable infiltration rate of the soil has decreased, and the amount of soil loss has also decreased. Surface biological crusts existing under perennial vegetation cover reduce soil stabilization infiltration rate. However, most of the vegetation on the Loess Plateau in the upper reaches of the Yellow River has been destroyed, resulting in massive soil and water loss. As a result, the Yellow River will of course flood many times.

From this point of view, if we want to solve the problem of Yellow River flooding, we must protect vegetation. The basic way to protect vegetation is to plant more trees. Now, our country has designated March 12 every year as Arbor Day, which is a positive manifestation. However, not only on Arbor Day, we must protect vegetation every day, so that our mother river can restore its former glory.