how does loess help with chinese agriculture

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Richthofen observed that the loess region of north China has been continuously cultivated for grain crops for over 4000 years almost without use of manure, and attributed the fertility to the porosity of loess, which enables it to absorb compound gases containing carbon and nitrogen from the atmosphere and to provide water and dissolved nutrients to plants by capillary rise in periods of dry weather.

Abstract. Loess soils are among the most fertile in the world, principally because the abundance of silt particles ensures a good supply of plant-available water, good soil aeration, extensive penetration by plant roots, and easy cultivation and seedbed production.

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Answer

What is the agricultural importance of loess?

 · The Loess Plateau is home to an estimated population upwards of 108 million, of which more than 70 % are reported to be living and working in agricultural areas (Wang and Li 2010).Agricultural land, including garden plots, forestland, and grassland, accounts for approximate 75 % of the total land area (An et al. 2014).Although the livestock production and …

What has been done to study loess in China?

Abstract: In the loess region of China efforts are made to stabilize the economy of the area by extensive afforestation and slope terracing. In Chung-hua district one fifth of the surface area is already covered with new woodland. Soil erosion has thus been reduced by about one half. Agriculture is intensified by melioration and organizational measures.

Where is loess found in China?

More dust slowly accumulates, and loess is formed. Loess often develops into extremely fertile agricultural soil. It is full of minerals and drains water very well. It is easily tilled, or broken up, for planting seeds. Loess usually erodes very slowly—Chinese farmers have been working the loess around the Yellow River for more than a thousand years.

Can China’s loess plateau be restored?

 · First Loess Plateau project: out of US$252 million (actual project costs), IDA contributed US$149 million; government/counterpart funding US$103 million. Second Loess Plateau project: IDA contributed US$50 million; IBRD US$99 million; and government/counterpart funding US$90 million. (China was still eligible for credits from the International …

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How does loess help China?

In the Loess Plateau, funding from the World Bank and the Chinese government helped restore 4 million hectares of land, more than doubling the incomes of local farmers, reducing erosion by 100 million tons of sediment annually, reducing flood risk, and dramatically increasing grain production.

Why is loess important in ancient China?

Loess often develops into extremely fertile agricultural soil. It is full of minerals and drains water very well. It is easily tilled, or broken up, for planting seeds. Loess usually erodes very slowly—Chinese farmers have been working the loess around the Yellow River for more than a thousand years.

How did loess help Chinese farmers?

This produced higher crop yields (79-80) and full utilization of natural rainfall to support dryland agricultural with water-saving irrigation (from 1997 to 2010). The system of water-harvesting has been greatly improved developed a new water- tank system with low cost specifically for the semiarid Loess Plateau (81).

How did loess affect China?

Home to more than 50 million people, the Loess Plateau in China’s Northwest takes its name from the dry powdery wind-blown soil. Centuries of overuse and overgrazing led to one of the highest erosion rates in the world and widespread poverty.

Is loess good for farming?

Loess soils are among the most fertile in the world, principally because the abundance of silt particles ensures a good supply of plant-available water, good soil aeration, extensive penetration by plant roots, and easy cultivation and seedbed production.

What is loess in China?

The Chinese Loess Plateau, or simply the Loess Plateau, is a plateau in north-central China formed of loess, a clastic silt-like sediment formed by the accumulation of wind-blown dust. It is located southeast of the Gobi Desert and is surrounded by the Yellow River.

What is the main crop produced in China?

RiceRice, China’s most important crop, is dominant in the southern provinces, many of which yield two harvests per year. In North China wheat is of the greatest importance, while in the central provinces wheat and rice vie with each other for the top place.

How do you say loess?

Many people pronounce loess the way it’s printed — LOW-ess. But that’s like pronouncing the word “island” like “IS-land” or calling Des Moines, Iowa “DEZ-mo-NEZ.” However, so many people say LOW-ess that in dictionaries it’s often mentioned as an acceptable pronunciation.

Does China have fertile soil?

Abstract. The black soil in northeast China is considered one of the most fertile soils in China. Consequently, the black soil region has become one of the most important regions for cereal grain production in China.

Where is China’s Loess Plateau?

Loess Plateau, Chinese (Pinyin) Huangtu Gaoyuan or (Wade-Giles romanization) Huang-t’u Kao-yüan, highland area in north-central China, covering much of Shanxi, northern Henan, Shaanxi, and eastern Gansu provinces and the middle part of the Huang He (Yellow River) basin.

What 3 physical features isolate China?

The large land was isolated from much of the rest of the world by dry deserts to the north and west, the Pacific Ocean to the east, and impassable mountains to the south. This enabled the Chinese to develop independently from other world civilizations.

What are loess soil deposits?

loess, an unstratified, geologically recent deposit of silty or loamy material that is usually buff or yellowish brown in colour and is chiefly deposited by the wind. Loess is a sedimentary deposit composed largely of silt-size grains that are loosely cemented by calcium carbonate.

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Where is the Loess soil experiment?

One of the oldest field experiments on a loess soil (chernozem) in Europe is the Static Fertilization Experiment at Bad Lauchstädt in Germany (Körschens and Müller, 1993). This was started in 1902 in one of the driest areas of Germany (mean annual rainfall 489 mm), and has a range of fertiliser treatments with and without farmyard manure as well as a nil (untreated) plot. Over the last 90 years, yields of winter wheat grown continuously have increased on all plots, including the nil plot, principally because of better cultivars, more advanced plant protection and increased deposition of nitrogen compounds from the atmosphere. Over the decade 1983–1992, the yields on the nil plot were 43–94% of the yearly maxima obtained with any fertiliser/manure treatment (Table 2). By comparison, in the Broadbalk Experiment at Rothamsted (UK), where the soil is derived from a much thinner loess layer over Clay-with-flints (Catt, 1969), the yields of the nil plots in continuous wheat were only 8–26% of the maxima obtained with fertilisers or manure in the same years (1983–1992) (Table 2). Most of the year-to-year variation in yield at Bad Lauchstädt is related to seasonal rainfall, and Körschens and Müller (1993) suggested that the large yields of the nil plot compared with those of other soils result from (a) deeper root penetration (2+ m) leading to more efficient use of water and available nutrients, and (b) weaker tillering without fertiliser, which gives more efficient utilisation of water in periods of drought.

How does the Chinese soil maintain fertility?

Free (1911) added that the long-term fertility of the Chinese loess is “partially explained by the prevalent use of night soil , and even more largely by the habit of spreading each year on fields located on the steps of the loess terraces fresh material dug from the perpendicular face of the next higher terrace. A certain amount of new soil material is thus regularly supplied. The material supplied by the frequent dust storms is no doubt also a factor in the maintenance of fertility; in fact the beneficial action of these storms is well known to the inhabitants both in China itself and in Central Asia”. He also reiterated earlier opinions that loess soils have “a peculiarly good physical texture…which allows the free movement of and absorption of water, aids the maintenance of a good tilth, and encourages a proper sanitary condition of the soil.”

Why are loess deposits so difficult to identify?

Because they have been weathered (decalcified), disturbed, mixed with other deposits beneath and extensively redistributed either by solifluction during the later episodes of the Devensian cold stage or by slopewash and streams during the Holocene, British loess deposits are often quite difficult to identify in the field, and soil analyses such as particle size distribution and mineralogy are necessary to confirm their presence Catt, 1978, Catt and Staines, 1982, Catt et al., 1971, Catt et al., 1974. In areas where other pre-Holocene surface deposits are virtually silt-free, the presence of quite small amounts of loess (10%) in soil horizons can be confirmed by analyses at ϕ (−log 2 mm) or even coarser size intervals Avery et al., 1959, Harrod et al., 1974. Similarly the coarse silt (16–60 μm) fraction of the Late Devensian loess in southern and eastern England contains a characteristic mineral suite, which can be used to identify a loess component in mixed soil or sediment horizons Catt et al., 1971, Catt et al., 1974, Gibbard et al., 1987, Recio Espejo et al., 1992, to distinguish the Devensian from older loess components (Avery et al., 1982) or to distinguish the loess from silt derived from other sources such as weathered Palaeozoic shales (Catt and Staines, 1982).

Where is the loess belt located?

Britain lies at the western margin of the main European loess belt, and has thin but quite extensive loess deposits. The thickest of these (up to 4 m locally) occur in southeastern areas close to the European mainland, mainly in north Kent, the west Sussex coastal plan and southeastern Essex (Fig. 2). Thinner accumulations (0.3–1.0 m) are more widespread but become patchy and sparse in northern and western areas. Their distribution in Fig. 2 is based on the 1:250,000 soil map of England and Wales (Soil Survey of England and Wales, 1983). Loess is almost unknown in Scotland. Most of the British loess was deposited in the Late Devensian Stage between approximately 18,000 and 13,000 BP Catt, 1978, Catt, 1988, Wintle, 1981, Parks and Rendell, 1992. It consequently occurs at or close to the present land surface, and is often the main parent material of soils on that surface.

What crops grow in the Nebraska loess?

Alway et al. (1917) showed in pot experiments that the raw calcareous loess subsoil of Nebraska grew leguminous crops, especially alfalfa, almost as well as the more organic and nitrogen-rich topsoil. However, non-leguminous crops such as corn were unproductive on the subsoil until its nitrogen content had been built up by growth of alfalfa for several years; this occurred through decay of the roots, which bear the nodules containing nitrogen-fixing bacteria, the alfalfa hay having been regularly harvested and removed. The fertility of the Nebraska loess subsoil for legumes contrasted with the virtual sterility of subsoils from more humid regions, even when the legumes grown in the latter subsoils were inoculated with extracts containing nitrogen-fixing bacteria. This difference was attributed to the greater availability to legumes of phosphorus and/or potassium in the unleached subsoil of the Nebraska loess. Alway et al. pointed out that early recognition of this could have influenced agricultural practices in drier regions even since prehistoric times. If so, it may partly account for the fertility attributed to loess soils in some drier areas.

How to restore yellow soil?

Attempts to restore the fertility of the “yellow” soils by growing nitrogen-fixing leguminous crops such as alfalfa or clover as green manures were often successful but locally revealed the further problem of acidity in some Illinois loess-derived soils. This was often difficult to treat with ground limestone because it extended into the deeper subsoil, probably in areas where the deeply leached Sangamon interglacial soil lay close to the ground surface. Accelerated erosion also proved to be a problem with the “yellow” soils, which have too little organic matter to bind the silt particles together.

Is loess soil erodible?

It was also recognized that loess soils are much more erodible than many other types. Consequently, on slopes the topsoil is often thinner (Schmidt et al., 1964) and contains less organic matter and total nitrogen (Aandahl, 1948) than on flatter sites. There were attempts to stabilise loess soils using fungal inoculations (Downs et al., 1955), solutions of salts with polyvalent cations (Rosen, 1968) and other “soil conditioners” to improve aggregate stability, permeability and infiltration. However, management techniques such as grass leys, conservation tillage processes Wicks and Smika, 1973, Fenster and Wicks, 1977, Siemens and Oschwald, 1978, Johnson and Moldenhauer, 1979, contour ridging, terracing and windbreaks (Skidmore and Hagen, 1977) have proved more successful in restricting water and wind erosion.

Where are loess deposits found?

Extensive loess deposits are found in northern China, the Great Plains of North America, central Europe, and parts of Russia and Kazakhstan.

How thick is loess?

Loess ranges in thickness from a few centimeters to more than 91 meters (300 feet). Unlike other soil s, loess is pale and loosely packed. It crumbles easily; in fact, the word “loess” comes from the German word for “loose.”. Loess is soft enough to carve, but strong enough to stand as sturdy walls.

What causes dust to settle in the desert?

On the far side of the desert, moisture in the air causes the particles and dust to settle on the ground. There, grass and the roots of other plants trap the dust and hold it to the ground. More dust slowly accumulates, and loess is formed. Loess often develops into extremely fertile agricultural soil.

Is loess a fertile soil?

Loess often develops into extremely fertile agricultural soil. It is full of minerals and drains water very well. It is easily tilled, or broken up, for planting seeds. Loess usually erode s very slowly—Chinese farmers have been working the loess around the Yellow River for more than a thousand years.

What is the purpose of the Loess Plateau restoration project?

Two projects set out to restore China’s heavily degraded Loess Plateau through one of the world’s largest erosion control programs with the goal of returning this poor part of China to an area of sustainable agricultural production.

How much did the Loess Plateau project cost?

First Loess Plateau project: out of US$252 million (actual project costs), IDA contributed US$149 million; government/counterpart funding US$103 million. Second Loess Plateau project: IDA contributed US$50 million; IBRD US$99 million; and government/counterpart funding US$90 million. (China was still eligible for credits from the International Development Association, the World Bank’s fund for low-income countries, when the projects were approved.)

How has sedimentation of waterways been reduced?

Sedimentation of waterways was dramatically reduced: The flow of sediment from the Plateau into the Yellow River has been reduced by more than 100 million tons each year. Better sediment control has reduced the risks of flooding with a network of small dams helping store water for towns and for agriculture when rainfall is low.

How did terracing affect food production?

Terracing not only increased average yields, but also significantly lowered their variability. Agricultural production has changed from generating a narrow range of food and low-value grain commodities to high-value products. During the second project period, per capita grain output increased from 365 kg to 591 kg per year.

What natural resources were protected by the Plateau?

Natural resources were protected: Uncontrolled grazing, subsistence farming, fuel wood gathering and cultivation of crops on slopes had left huge areas of the Plateau devastated. The project encouraged natural regeneration of grasslands, tree and shrub cover on previously cultivated slope-lands. Replanting and bans on grazing allowed the perennial vegetation cover to increase from 17 to 34 percent.

How many people were lifted out of poverty in China?

More than 2.5 million people in four of China’s poorest provinces – Shanxi, Shaanxi and Gansu, as well as the Inner Mongolia Autonomous Region – were lifted out of poverty. Through the introduction of sustainable farming practices, farmers’ incomes doubled, employment diversified and the degraded environment was revitalized.

How many people have benefitted from the China project?

The projects’ principles have been adopted and replicated widely. It is estimated that as many as 20 million people have benefited from the replication of the approach throughout China.

What are the environmental problems of the Loess Plateau?

By the end of the 20th century, the area was so ravaged that one could ride for miles without seeing more than a few scattered trees and some small clumps of grass. Erosion on the Loess Plateau has come to be viewed as one of China’s most significant environmental problems. It is estimated that an average of 0.4 inch (1 centimeter) of loess is lost from the surface of the entire plateau each year. The Loess Plateau contributes 90 percent of the sediment load of 1.6 billion metric tons per year for the Huang He. This massive silt load dramatically affects river navigation, seasonal flood events, and urban-industrial water quality for the middle and lower portions of the Huang He. It also represents the loss of a precious soil resource that the people of the Loess Plateau can ill afford to lose. Agriculture is by far the most important economic activity in the region. In part because of the severely degraded environment, the Loess Plateau is one of the poorest regions of China. Since the late 20th century, increased efforts have been made to combat soil erosion in the area by replanting forests and terracing large areas of hillside.

What was the landscape like in the Loess Plateau?

In early historical times, the landscape of the Loess Plateau was quite different than it is today. Much of the land was covered with dense forests and grasslands. Over thousands of years, poor land management practices and long-term extensive timber harvesting left much of the plateau denuded, which, in turn, accelerated the rates of erosion.

How long has the Loess Plateau been logged?

Portions of the Loess Plateau have been logged and cultivated for 7,000 years. Large sections of the region were opened up for agriculture and timber harvesting during the Han Dynasty (206 bc – ad 220). During the Han period, much of the plateau was a very important agricultural region that provided grain, lumber, and livestock to the expanding Chinese empire centered on the Wei River and the Huang He—the cradle of Chinese civilization.

Where is the Loess Plateau located?

Loess is distributed throughout many areas of northern China, but the greatest concentrations of loess are found in central China north of the Qin Mountains along the middle reaches of the Huang He (Yellow River). This area, the Loess Plateau, covers an area of roughly 150,000 square miles (400,000 square kilometers). It is the largest continuous deposit of loess in the world. Its thick layers of loess originate thousands of miles away on the steppes of Central Asia. The plateau’s loess, which has been eroding into the rivers and streams of the region for thousands of years, gives the Huang He its characteristic yellow color.

How deep is the Loess Plateau?

The loess forms an almost continuous deposit on the land, ranging from about 165 to 260 feet (50 to 80 meters) in depth in most places. In some parts of the plateau, however, the loess deposits are as much as 1,000 feet (300 meters) thick. Because of its unconsolidated nature, when bare loess is soaked with water, significant erosion can occur. This is particularly a problem during the summer, when this normally dry region receives bursts of intense rainfall. Water erosion has created deep ravines, gorges, and barren, furrowed hills in much of the landscape.

What is a loess?

Loess ( US: / lɛs, ˈloʊ.əs, lʌs /, UK: / lɜːs /; from German: Löss [lœs]) is a clastic, predominantly silt -sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of Earth’s land area is covered by loess or similar deposits.

Why is loess rich?

Soils underlain by loess tend to be excessively drained. The fine grains weather rapidly due to their large surface area, making soils derived from loess rich. One theory states that the fertility of loess soils is due largely to cation exchange capacity (the ability of plants to absorb nutrients from the soil) and porosity (the air-filled space in the soil). The fertility of loess is not due to organic matter content, which tends to be rather low, unlike tropical soils which derive their fertility almost wholly from organic matter.

What is the use of radiocarbon dating in Loess?

Besides luminescence dating methods, the use of radiocarbon dating in loess has increased during the past decades. Advances in methods of analyses, instrumentation and refinements to the radiocarbon calibration curve have enabled to obtain reliable ages from loess deposits for the last 40-45 ka. However, the use of this method relies on finding suitable in situ organic material in deposits such as charcoal, seeds, earthworm granules or snail shells.

What are loess ridges called?

In several areas of the world, loess ridges have formed that are aligned with the prevailing winds during the last glacial maximum. These are called “ paha ridges” in America and “greda ridges” in Europe.

Why are the Loess Hills fertile?

The Loess Hills of Iowa owe their fertility to the prairie topsoils built by 10,000 years of post-glacial accumulation of organic-rich humus as a consequence of a persistent grassland biome. When the valuable A-horizon topsoil is eroded or degraded, the underlying loess soil is infertile, and requires the addition of fertilizer in order to support agriculture .

Where is the largest loess deposit in the United States?

The largest deposit of loess in the United States, the Loess Hills along the border of Iowa and Nebraska, has survived intensive farming and poor farming practices. For almost 150 years, this loess deposit was farmed with mouldboard ploughs and fall tilled, both intensely erosive.

How thick is loess?

Loess deposits may become very thick, more than a hundred meters in areas of Northwestern China and tens of meters in parts of the Midwestern United States. It generally occurs as a blanket deposit that covers areas of hundreds of square kilometers and tens of meters thick. True Loess often stands in either steep or vertical faces. Because the grains are angular, loess will often stand in banks for many years without slumping. This soil has a characteristic called vertical cleavage which makes it easily excavated to form cave dwellings, a popular method of making human habitations in some parts of China. Loess will erode very readily.

What is the largest loess plateau in China?

Loess Plateau, Chinese (Pinyin) Huangtu Gaoyuan or (Wade-Giles romanization) Huang-t’u Kao-yüan, highland area in north-central China, covering much of Shanxi, northern Henan, Shaanxi, and eastern Gansu provinces and the middle part of the Huang He (Yellow River) basin. Averaging about 4,000 feet (1,200 metres) in elevation and covering some 154,000 square miles (400,000 square km), it is the world’s largest loess plateau. The region is overlain by a mantle of fine-grained, wind-deposited, yellowish alluvium known as loess, which is also carried in suspension by the Huang He. The loess layers average 165–260 feet (50–80 metres) in thickness and mask the detailed relief of the underlying surfaces. The loess is highly subject to erosion because of sparse vegetation, heavy precipitation in summer, and gullying. The government has conducted programs to control erosion through afforestation and terracing on an extensive scale to permit better agricultural use of the land. Grain is the major crop on the plateau.

Why is the Loess Plateau subject to erosion?

The loess is highly subject to erosion because of sparse vegetation, heavy precipitation in summer, and gullying. The government has conducted programs to control erosion through afforestation and terracing on an extensive scale to permit better agricultural use of the land. Grain is the major crop on the plateau.

How tall is the Loess plateau?

Averaging about 4,000 feet (1,200 metres) in elevation and covering some 154,000 square miles (400,000 square km), it is the world’s largest loess plateau. The region is overlain by a mantle of fine-grained, wind-deposited, yellowish alluvium known as loess, which is also carried in suspension by the Huang He.

Where is the Loess Plateau?

Loess Plateau, Chinese (Pinyin) Huangtu Gaoyuan or (Wade-Giles romanization) Huang-t’u Kao-yüan, highland area in north-central China, covering much of Shanxi, northern Henan, Shaanxi, and eastern Gansu provinces and the middle part of the Huang He (Yellow River) basin. Averaging about 4,000 feet (1,200 metres) in elevation …

What is the major crop on the plateau?

Grain is the major crop on the plateau. Loess Plateau, Shanxi province, China. This vast plateau of some 154,000 square miles (400,000 square km) forms a unique region of loess-clad hills and barren mountains between… This article was most recently revised and updated by Amy Tikkanen, Corrections Manager.

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