Poor red
soil
0
Clay stone
Hard
Low
Medium
Low
No change
Sandy red
soil
0(<10)
Silt tone
Hard
Low
Medium
High
Poorer rapid
Red soil
mixing
rock
~25
Silt stone,
conglomerate
Medium
(rock)
Medium
Medium
Low (rock)
Poorer – rapid
Yellow
soil
Sandy
yellow
soil
0(<10)
Alluvium
Soft
Medium
High
High
Poorer – rapid
Poor yellow
soil
0(<10)
Quartz gravel
Medium
Medium
High
Low
Poorer
Yellow soil
mixing
gravel
>50
Quartz gravel
Hard
Low
High
Medium
Poorer – rapid
2 Beyond the Horizons: Challenges and Prospects for Soil Science and Soil. . .
69