What is the experience of controlling sandstorms abroad?
After World War I, because of the high price of wheat, the United States began to immigrate to the Southern Plains for dry farming. The farmers opened up this vast virgin land on a large scale. In order to maximize profits, after the fertility of the cultivated land was exhausted, they immediately abandoned the land and turned to cultivate new unfamiliar land. As a result, with the wind erosion caused by successive droughts in the late 1920s and early 1930s, the process of desertification in reclamation areas was extremely rapid, which made the southern great plains a "sand nest" with frequent sandstorms, and 20 million hectares of grassland soil was scraped away with a sand layer of 1m thickness.
1934 The sandstorm in May was the strongest sandstorm in American history. On May 12 of that year, the black storm originated in Kansas, Sacramento and Colorado in the United States, and the dust covered the sky, forming a dust belt with a height of 3 kilometers, a length of 1.440 kilometers and a width of 400 kilometers, covering two-thirds of the United States. More than 300 million tons of soil was blown into the Atlantic Ocean hundreds of kilometers away, and160,000 farmers were forced to leave the Great Plains.
According to the statistics of the American Soil Protection Bureau, during the 40 years from 1935 to 1975, the area destroyed by sandstorms in the American Great Plains reached 400,000 hectares every year, with a maximum of 600,000 hectares. Due to the sandstorm, the annual replay area of cotton fields in South China reached 80%, and the livestock carrying capacity decreased from 20 million at the beginning to more than11million later.
In order to control land desertification and sandstorms in the Great Plains, the United States fought a protracted ecological defense war. After years of painful exploration, the United States has formed a set of all-round sand prevention experience, which has successfully reduced the occurrence of sandstorms. Generally speaking, the United States has "five tricks" to control sandstorms:
Trick 1: "heaven and earth are combined". Combination of weather forecast and foundation treatment. Before each gale comes, the meteorological department accurately predicts the path of the gale 48 hours in advance, and then sprinkles it on the exposed farmland in the area where it passes, making it moist and firm, cutting off the source of the sandstorm.
Trick 2: Sand fixation is good. Plant fiber, old newspaper pulp and sticky substances are mixed together and sprayed on the surface of dust with green dye, which not only fixes the dust, but also beautifies the environment. In addition, the viscous sand-dust curing agent can be sprayed on the desert, and its penetration can reach 1 cm. The surface layer is not afraid of pressure and is free from dust, so it can be used for walking and driving, and it is very firm. One spraying can lock the sand-dust 1~2 years, and the cost is much lower than that of planting trees and grass.
Trick 3: hell pays the bill. Land owners and homeowners in the desert artificially create dust around them or fail to take measures to control it. They are fined 500 dollars every day. Those who refuse to implement it will be fined $2,000 per day. The person in charge and employees of contractors working in the desert should have at least four hours of environmental classes before starting work, and they are required to use water to eliminate dust while working. If it fails to meet the requirements, it will be ordered to stop work or fined.
Trick 4: improve farming techniques. Intercropping, interplanting and stubble-keeping of crops at different maturity and sowing dates, vigorously promoting no-tillage method and using special agricultural machinery to shallow turn the land effectively prevented sandstorms.
Trick 5: Stop grazing and return to the forest. The government encourages farmers to return farmland to forests. In less than five years, the area of returning farmland to forests has reached15 million hectares, accounting for about 10% of the total cultivated land in China, and the area of soil erosion in the United States has decreased by about 40%.
Sow green sand in the former Soviet Union.
The grassland of North Kazakhstan in the former Soviet Union accounts for 1/5 of Kazakhstan's land area, and is called "the three fertile grasslands in the northern hemisphere" together with the grassland in northeast China and the Great Plains in the Midwest of the United States. The average annual precipitation in this grassland is 255 ~ 317mm, concentrated in May ~ September, while the annual evaporation is 650 ~ 750mm, and there are almost no windless days.
/kloc-before 0/954, the grassland population in northern Kazakhstan was still very small, with little cultivated land and few sandstorms. 1954 years later, the former Soviet Union proposed to establish an "Oriental Commodity Grain Base" here, and began a large number of immigrants to open up wasteland here. From 1954 to 196 1 year, 41500,000 hectares of grassland were reclaimed from the Ural Valley to western Siberia, and 6170,000 hectares were reclaimed in 1963.
1959, the population of grassland in northern Kazakhstan surged to 2.753 million, and then increased at the rate of 200,000 every year. They cut down many trees and planted grass as fuel for deep ploughing. The plunder of nature has finally turned this grassland with abundant water plants into one of the four major dust sources in the world. At first, the fertile black soil was rolled up here. After a long period of wind erosion and salinization, a unique white sandstorm has formed.
In order to control the sandstorm source area, the former Soviet government began to control sandstorms by planting trees, returning farmland to grassland and adjusting agricultural structure. They built a huge shelterbelt along the grassland and forest grassland. By 1985, about 5.5 million hectares of shelterbelts had been built. At the same time, the former Soviet government also took measures to control sandstorms by planting green planes and adjusting agricultural structure.
After so many years of control, although there are still sandstorms on the grasslands of North Kazakhstan, the frequency and scale of sandstorms have been greatly reduced compared with when land was reclaimed.
Australia revolves around pasture sand control
Australia is a vast country with a sparse population, and its agriculture is mainly animal husbandry, so it is called "the country riding on the back of sheep". Land desertification in Australia is mainly reflected in grassland degradation, and the vast plains are also the source of sandstorms in Australia. Therefore, the control of sandstorms in Australia is mainly around pastures.
Sand control in pastoral areas of Australia mainly includes the following "three axes":
(1) Strictly implement rotational grazing. In Australia, farms are generally divided into squares with cement columns and barbed wire, and different squares are different grazing areas. Australians usually don't graze continuously in the same pastoral area, but take turns to use different grazing areas so that the pasture has enough time to recover.
(2) Vigorously promote captive breeding. In order to prevent sheep from pulling weeds and destroying vegetation, the Australian government has also vigorously promoted captivity, especially in places with bad ecology. By mowing grass and keeping livestock in captivity, grass roots and stubble are retained, which also plays a role in sand fixation.
(3) scientifically match the number and species of herds. Animal husbandry in Australia is very strict, and it is not up to farmers to decide what to raise and how much to raise. The Australian government conducts a general survey of all pastures every year to determine the stocking capacity of the following year. In the same herd, the number of cattle and sheep is also scientifically calculated, thus realizing the organic combination of ecological benefits and economic benefits.
In addition, the Australian government has a sound legal system and strict law enforcement, and offenders are prosecuted, thus ensuring the smooth implementation of the above system.
Gold in the Middle East is paved with green.
The Middle East, including West Asia and North Africa, is also one of the four active sandstorms in the world. Due to the increase in population, the Middle East, where most of the land is barren, began to cultivate a large number of pastures. Deforestation, overgrazing and large-scale reclamation have led to the destruction of natural vegetation, accelerated desertification and frequent sandstorms.
In order to protect the fragile ecological environment, countries in the Middle East have taken some measures to prevent sandstorms according to their different situations.
(1) Formulate laws and regulations prohibiting grassland reclamation and establish grassland protection areas. At present, there are more than 60 such pasture reserves in Syria and Jordan alone. However, most of these plans have no obvious effect, and pastures continue to deteriorate. The main reason is that these ecosystems are easily destroyed, and the number of livestock far exceeds the land carrying capacity of this area.
(2) Vigorously invest in greening cities, which are mainly concentrated in oil-rich Gulf countries. It is understood that the GCC countries have spent billions of dollars in recent years to build gardens and green spaces inside and outside cities, and the GCC countries have spent the most on greening projects in the world. Per capita green area of GCC countries 12 square meters. In cities like Doha and Dubai, greening is very good, and the cost of greening and nursing is also very high. It is no exaggeration to say that every green land in the Gulf countries is a piece of gold.
(3) Planting trees. Algeria's "Green Dam Project" is an ecological construction project that attracts worldwide attention. In the early 1970s, a large-scale Green Dam project began to be built. The main project of this green belt is in the northeast of Algeria, and it is also a transnational project of Morocco, Algeria, Tunisia, Libya and Egypt.
(4) Water conservation and ecological protection are mainly in Israel. Unlike the Gulf countries, Israel is not rich in oil, but this desert country has made use of its powerful economic strength and cutting-edge agricultural technology to vigorously promote water-saving technologies such as drip irrigation, carry out ecological construction and agricultural production, and become a major exporter of agricultural products.