Natural regions II: temperate grasslands and Mediterranean lands

Detail

1. Temperate grasslands: where they are and why

• Temperate grasslands are wide, treeless or nearly treeless lands covered with grass. They lie in the mid-latitudes, about 30°–55° N and S, deep in the interiors of continents, far from the sea.
• Why the interior matters:
• They are far from the ocean, so moist sea winds lose most of their water before they arrive.

• The result is a continental climate: hot summers, very cold winters and a wide yearly range of temperature.

• In the Köppen scheme (a way of grouping world climates by temperature and rainfall), the drier edges of these grasslands fall under BSk. BSk means a cold, semi-arid steppe climate.

2. Climate, soil and natural vegetation

Feature	Detail
Rainfall	25–75 cm a year, mostly in spring and early summer, often as convectional showers
Winter	Very cold. Snow lies on the ground and frost is common
Summer	Warm to hot, and short
Soil	Chernozem (Russian for "black earth") and the chestnut soils at the drier margins
Vegetation	Tall grass in the wetter parts and short grass in the drier parts. Trees grow only along rivers

• Chernozem: a deep soil with a thick black top layer that is rich in humus (rotted plant matter). It is among the most fertile soils in the world [4].
• It forms where 450–600 mm of rain falls each year, mostly in spring or early summer, with cold winters and short, hot summers [4].
• Chernozem covers about 230 million hectares worldwide, mainly in the steppes of Eurasia and the plains of North America [4].

• How it forms:

  • Grass roots die every year and add a lot of humus to the soil.
  • Low rain means little leaching (water washing nutrients down and out of the soil).
  • Calcium and humus therefore stay in the top layer, and the soil becomes black and crumbly.

• Why there are few trees:

• Low rain: there is not enough water for deep-rooted trees.
• Frost: hard winters kill young trees.
• Fire: dry grass burns often. Grass grows back from its roots, but tree seedlings die.
• Grazing: wild animals such as the bison, and later cattle and sheep, eat young shoots.

3. Economy: extensive grain farming and ranching

• Extensive commercial grain cultivation: farming on very large, machine-run farms to grow grain (mainly wheat) for sale. The land is huge and labour is scarce, so the work is done by tractors and combine harvesters.
• Low yield per hectare: each hectare gets little fertiliser and labour, so it produces less.
• High yield per worker: one farmer with machines handles hundreds of hectares, so output per person is very high.

• The main limit is the harvest season. Winter wheat is grown in milder areas and spring wheat in colder areas.

• Livestock ranching: keeping large herds of cattle or sheep on big fenced farms (ranches) to sell meat, wool and hides. It is common in the drier parts that are not good for ploughing.

• Railways opened these lands. Trans-continental railways carried settlers in and took grain out to ports. Without them, the interiors had no route to world markets.

4. The six major temperate grasslands

Grassland	Continent / country	Location anchor	Key facts
Prairies	North America: USA, Canada	Interior plains east of the Rockies. Canadian Prairie Provinces: Alberta, Saskatchewan, Manitoba	The "wheat basket" of the world; wheat and maize; opened by trans-continental railways; Chinook wind
Pampas	South America: Argentina, Uruguay	Around the Rio de la Plata estuary	Wheat and beef from large estancias (big ranch-farms); South America's densest rail network, which spreads out from Buenos Aires
Steppes	Eurasia	From Ukraine across southern Russia and Kazakhstan to Mongolia	Wheat exported through Black Sea ports; traditional home of pastoral nomads; Soviet Virgin Lands campaign of the 1950s
Velds	Africa: South Africa	South African plateau. The high veld is about 1,200–1,800 m high, around Johannesburg and Pretoria	Maize, wheat, merino sheep; gold of the Witwatersrand
Downs	Australia	South-eastern Australia, mainly the Murray-Darling basin	Wheat, merino sheep; artesian wells
Canterbury Plains	New Zealand	Eastern South Island, in the rain shadow of the Southern Alps	Grain and sheep (Canterbury lamb)
Puszta	Europe: Hungary	Great Hungarian Plain, in the middle Danube basin	Wheat and maize; once a cattle and horse grazing land

Prairies

• Chinook: a warm, dry wind that blows down the eastern slopes of the Rockies in winter and spring.
• Moist air rises over the Rockies, cools and drops its rain or snow on the western (windward) side.
• The now-dry air sinks down the eastern side and warms up as it is squeezed.

• The warm wind can melt snow in hours. It is called the "snow eater". It clears pastures for grazing and makes early sowing possible.

• Wheat belts: spring wheat is grown in the colder north (Canada, North Dakota) and winter wheat in the milder south (Kansas). Maize is grown on the wetter eastern side.

• Dust Bowl (1930s):
• Cause: farmers ploughed up the prairie grass to plant dryland wheat. As demand for wheat rose, millions more acres were ploughed [6].
• Trigger: a severe drought hit the south-western Great Plains between 1930 and 1940 [6]. NASA research links it to unusual tropical sea-surface temperatures, made worse by land–air feedback [7].
• Result: the bare, overused soil blew away in dust storms, some reaching the Atlantic Ocean. About 400,000 people left the Great Plains [6][8].
• Lesson: keep grass cover, use shelter belts (rows of trees that break the wind) and practise contour ploughing (ploughing across a slope, not up and down it).

Pampas

• The soil is deep and fertile and the land is flat, with mild winters. Both wheat and alfalfa, a fodder crop for cattle, grow well.
• Refrigerated ships (from the late 19th century) let chilled beef be exported to Europe. Railways bring grain and cattle to Buenos Aires and Rosario.

Steppes

• The black-earth belt of Ukraine and southern Russia is one of the world's main wheat-exporting areas. Grain leaves from Black Sea ports such as Odesa.
• Pastoral nomads: herders who move with their animals (horses, sheep, camels) to find grass, for example the Kazakhs and the Mongols.
• Virgin Lands campaign: a Soviet plan under Nikita Khrushchev, started in 1953 and officially launched in March 1954. It ploughed up the grasslands of northern Kazakhstan and western Siberia for wheat, worked by Slavic settlers [9].
• Result: grain output rose at first. Over the following decades, soil erosion led to an ecological disaster [9].

Velds

• The high veld is high up, so summers are mild even at about 26° S. Rain falls in summer.
• Witwatersrand ("ridge of white waters") around Johannesburg holds the world's richest gold-bearing rocks. Mining, farming and industry together make this South Africa's economic core.

Downs

• Artesian well: a well where water rises by itself under pressure. The water-bearing rock layer is fed by rain on higher ground far away.

• In Australia this water comes from the Great Artesian Basin. It supplies water to stock (sheep and cattle) on the dry Downs. The water is often too salty for crops.

• The Murray and its tributary the Darling drain the main wheat-sheep belt of New South Wales and Victoria.

Canterbury Plains

• Rain shadow: the dry side of a mountain range.
• Moist westerly winds from the Tasman Sea rise over the Southern Alps and drop their rain on the west coast.

• The dry air descends on the east side, so the Canterbury Plains are dry. Grass grows there, not forest.

• Mixed farming of grain and sheep. Canterbury lamb is exported in frozen form. The main town is Christchurch.

5. Why the grasslands matter: world food security

• These grasslands produce most of the world's traded wheat and maize. A drought, war or price shock here raises food prices worldwide.
• 2022 Ukraine war:
• Russia's invasion blocked Ukraine's Black Sea ports, and world grain prices jumped.
• The Black Sea Grain Initiative was agreed in July 2022 between the UN and Türkiye, with Ukraine and Russia as signatories. It ran until July 2023 [2].
• It moved nearly 33 million tonnes of grain and food from three Ukrainian ports to 45 countries [2].
• Maize (corn) was the largest item, over 16.8 million tonnes, followed by wheat at 8.9 million tonnes. China was the largest buyer, at about 8 million tonnes [2].

• About 40% of the wheat went to low- and lower-middle-income countries [2].

• Dust Bowl: an early warning of how drought and overuse of the soil can damage these lands. Climate change is expected to make such risks worse.

6. Exam trap: temperate vs tropical grasslands

Temperate (mid-latitude)	Tropical (low-latitude)
Prairies (North America)	Savanna (Africa, especially East Africa)
Pampas (Argentina)	Llanos (Orinoco basin, Venezuela and Colombia)
Steppes (Eurasia)	Campos (Brazilian Highlands)
Velds (South Africa)	Tropical grassland in northern Australia
Downs (Australia)
Canterbury Plains (New Zealand), Puszta (Hungary)

• Temperate grasslands have cold winters and short grass. Tropical grasslands are hot all year with a wet and a dry season, and have tall grass with scattered trees.

7. Mediterranean lands (Köppen Cs)

• Mediterranean climate (Cs): a warm-temperate climate with a dry summer ("s" = summer dry). It occurs between about 30° and 45° latitude on the western sides of continents.
• Where:

Region	Continent	Local scrub name
Lands around the Mediterranean Sea	Europe, North Africa, West Asia	Maquis
Central California	North America	Chaparral
Central Chile	South America	Matorral
Cape region of South Africa	Africa	Fynbos
South-western Australia (Perth, Adelaide)	Australia	Mallee scrub

• Why the rain falls in winter:
• Summer: the subtropical high-pressure belt moves towards the pole. Dry, sinking air gives hot, clear, dry summers.

• Winter: the belt moves towards the equator. The westerlies (winds blowing from west to east in the mid-latitudes) and their cyclones bring mild, rainy winters.

• Vegetation: evergreen, drought-resistant scrub and trees such as the cork oak and olive.

• Their small, thick, waxy leaves lose less water.
• Their deep roots reach water far below the surface.

• Their thick bark helps them survive fire.

• Economy: the "orchard lands of the world"

• Fruit: olives, citrus (oranges, lemons), grapes and wine, figs.
• Winter wheat grows in the rainy winter.
• Tourism: sunny summers draw visitors to the coasts of Spain, Italy, Greece and California.

• Summer is dry, so irrigation is needed for fruit and vegetables.

• Rising problems:

• Summer wildfires: dry scrub plus hot, windy summers make a ready fuel. Examples are California and Greece.
• Water stress: rain comes in the wrong season (winter), and cities, farms and tourism compete for water. Warming is making the summers longer and drier.

Prelims Hooks

• Chernozem = "black earth". It is the soil of the Steppes, Prairies and Pampas. It forms under 450–600 mm of spring and early-summer rain with cold winters.
• Chinook = a warm, dry "snow eater" wind on the eastern slopes of the Rockies, in the Prairies. Do not confuse it with the Foehn (Alps).
• Grassland–country matches: Pampas → Argentina/Uruguay, Velds → South Africa, Downs → Australia, Canterbury → New Zealand, Puszta → Hungary, Steppes → Ukraine to Mongolia.
• Trap: the Llanos (Venezuela/Colombia), Campos (Brazil) and Savanna (Africa) are tropical. The Prairies, Steppes, Pampas, Velds and Downs are temperate.
• The Canterbury Plains are dry because they lie in the rain shadow of the Southern Alps.
• Artesian wells of the Great Artesian Basin water livestock on the Australian Downs. The Witwatersrand gold field lies in the high veld.
• Extensive grain farming = low yield per hectare, high yield per worker.
• Black Sea Grain Initiative (July 2022): brokered by the UN and Türkiye. Maize was the largest export under it, not wheat.
• Mediterranean scrub names: maquis (Mediterranean Sea), chaparral (California), fynbos (Cape). Rain falls in winter, from the westerlies.
• The Virgin Lands campaign (launched 1954, Khrushchev) ploughed the steppes of northern Kazakhstan.

Mains Points

• Grasslands as global breadbaskets (GS-I/GS-III):
• These lands have huge flat areas, fertile chernozem, mechanised farms and railways to ports. Together these give a large exportable surplus of grain.

• The world's dependence on a few such lands makes the food supply fragile. The 2022 Black Sea blockade raised prices for import-dependent countries in Africa and West Asia.

• Human misuse and land degradation (GS-III):

• The Dust Bowl (1930s USA) and the Virgin Lands campaign (Kazakhstan) show that ploughing semi-arid grassland without soil conservation leads to wind erosion, crop failure and people leaving the land.

• Lesson for India's dry lands in Rajasthan and the Deccan: keep grass cover, plant shelter belts and match farming to rainfall.

• Mediterranean lands under climate stress (GS-I/GS-III):

• Hotter, longer dry summers bring more wildfires, groundwater depletion and conflict between farms, cities and tourism over water.

• Responses include drip irrigation, desalination, fire-break management and drought-tolerant crops.

• Distribution logic (GS-I):

• Grasslands lie in continental interiors with summer rain. Mediterranean lands lie on the west coasts at 30°–45° with winter rain.
• Both patterns follow from distance from the sea and the seasonal shifting of the pressure belts.