Black soil and forests
What black soil is
Black soil is dark because it has a lot of humus, which is rotted plant and animal matter. Humus holds water and food for plants. Northeast China has one of the few large black soil regions in the world. The dark layer can be tens of centimetres thick.
Why it formed here
- Cold winters slow the rotting, so plant matter piles up.
- Thick grass grew on the plains for thousands of years.
- Summer rain helps plants grow well.
Forests
The Greater and Lesser Khingan and Changbai hills carry big forests of pine, larch and birch. China's timber industry started here. Today many forests are protected, because trees hold soil and keep rivers clean.
A grain base
The Northeast Plain is wide, flat and has deep soil, so machines can work easily. Summers are warm and rainy, which suits crops, but the growing season is short, so there is only one crop a year.
- Corn in the central and southern plains.
- Rice in wetter areas, famous for good taste.
- Soybean and other crops in the north.
- Farms are large and use many machines.
The region sends a large share of China's grain to other parts of the country, so it is called a commodity grain base.
The risk
Years of heavy ploughing, wind and rain wash away black soil. Farmers now use conservation tillage: leave stalks on the field, plant tree belts, plough along the slope contours.
Heavy industry and revitalisation
Heavy industry makes big, heavy goods: steel, machines, ships and vehicles. The Northeast had everything for it: coal, iron ore, oil (for example from Daqing), forests and railways.
- Anshan: steel.
- Shenyang: machines.
- Changchun: cars.
- Daqing: oil.
Why it needed renewal
Old factories used old machines and the mines ran low. Many were slow to compete, and many workers lost jobs.
Revitalisation
Since the early 2000s, the region has been renewing: upgrading machines, building robots and new energy (wind, solar), growing food processing and tourism (snow and ice festivals), and training workers for new jobs.
Try it: protect the soil
- In the 3D, drag the "years of ploughing" slider to 100 with no protection. Write the grain index.
- Now tick "Protect soil". Slide to 100 again. Write the new number. Which is higher?
- At home: plant seeds in two pots. Leave one pot soil bare. Cover the other with dry leaves. Water both lightly from above. In which does the soil wash out less?
Key formulas and definitions
- Black soil: dark soil rich in humus, found on the Northeast Plain
- Humus: rotted plant and animal matter that feeds the soil
- Commodity grain base: area that sends large amounts of grain to other regions
- Heavy industry: making heavy goods such as steel, machines, ships and cars
- Revitalisation: renewing an old industrial area with new technology and jobs
- Conservation tillage: farming that leaves cover on the soil to stop erosion
Worked examples
1. Why is black soil black?
It has lots of humus, rotted plant matter. Cold winters slow rotting, and grass grew here for ages, so humus piled up and made the soil dark and rich.
2. Why does Northeast China grow only one crop a year?
Winters are long and freezing and the warm season is short. Only one crop can finish growing and ripening, such as corn, rice or soybean.
3. Give two reasons heavy industry grew in Northeast China.
It has coal, iron ore and oil close by, and railways that carry heavy goods. Early factories could use these on the spot.
Common mistakes
- Thinking black soil is black because of volcanic rock. Here, the dark colour is from humus.
- Believing the region grows two or three crops a year like the south. The cold means one crop a year.
- Forgetting black soil can be lost. It is rich, but ploughing, wind and water can thin it.
- Thinking "revitalisation" means closing the industry. It means renewing it with new machines and jobs.