soil problems and management

Question 1

define soil erosion

Answer 1

wearing away of the topsoil

Question 2

why is the thin topsoil layer important

Answer 2

most fertile layer, provides nutrients and structure for agriculture

Question 3

what does the FAO estimate about productive land?

Answer 3

5-7 million hecares of productive land is lost every year to erosion + degradation

Question 4

what are 2 ways that soil erosion can damage the environment?

Answer 4

-deposition of sediment onto roads, drainage ditches etc.
-damage to quality of water bodies, through excess inputs of sediment, may lead to eutrophication

Question 5

3 types of water erosion

Answer 5

rill + gully erosion
riverbank erosion
sheet erosion

Question 6

main method of controlling water erosion

Answer 6

reduce amount of surface flow water

Question 7

3 methods of managing water erosion

Answer 7

contour ploughing - reduces overland flow
field drains + ditches
manure to stabalise topsoil

Question 8

4 types of wind erosion

Answer 8

saltation -bouncing
creeping - wind rolls the particles
suspension - in air
attrition - lifted and drop

Question 9

3 methods of managing wind erosion

Answer 9

planting trees as wind breaks eg. Great Green wall in Niger
organic matter to improve soil cohesion + structure
increasing plant cover

Question 10

what is waterlogging

Answer 10

soil becomes oversaturated with water
can be surface fed or groundwater fed

Question 11

what can waterlogging cause and why

Answer 11

lack oxygen in root zone, plants cant respire aerobically, root tissue can decompose

Question 12

what is salinisation

Answer 12

build up of salt in soil to a toxic level for plants

Question 13

where is salinsation most common

Answer 13

hot semi arid areas

Question 14

two negatives of salinsation

Answer 14

reduce root water uptake
affects around 10% of all arable land

Question 15

management and criticism of salinsation

Answer 15

flush out soil with lots of water
causes salinisation wherever the flush water goes

Question 16

2 causes of structural deterioration

Answer 16

reduction in organic matter
soil compaction

Question 17

one way of managing a reduction in soil organic matter (struc det.)

Answer 17

planting trees as litter to replenish organic matter

Question 18

what is soil compaction caused by

Answer 18

livestock and farm machinary

Question 19

two ways of managing soil compaction (struc det.)

Answer 19

not working soil when wet
low tyre inflation of machinery