human impact on soil Flashcards
what is organic soil made of?
partially decomposed leaves and grass
what is the function of organic soil?
limit temperature variation and water loss
what is top soil made of?
chiefly of rock and humus
what is the function of top soil?
-rich in nutrients, oxygen and water– plants get most of their nutrients from this layer
what is subsoil made of?
large rock with a little humus
what are the 2 functions of subsoil?
- fair amount of nutrient, oxygen and water
- plants that have deeper roots can get some nutrients from this layer
what is bedrock made of?
rock layer
what is the function of bedrock?
this is where the soil is formed from
what is humus?
decaying plant and animal matter
what is every soil type made of?
sand, silt, clay
what is loam soil made of?
sand, silt, clay
how large are spaces in loam soil?
large enough for air and water to flow in
can plants grow through spaces in loam soil?
yes
what is clay soil made of?
mostly clay
how large are spaces in clay soil?
no air and water can get in
can plants grow through clay soil?
no, they cannot push through it
what is sandy soil made of?
mostly sand
how large are spaces in sandy soil?
very big but does not hold water easily
can plant roots grow through sandy soil?
no, they cannot hold onto the soil
what is silt soil made of?
mostly silt
can silt soil hold water and nutrients?
yes
can plants grow through silt soil?
yes
silt soil is too light, so it ____ easily
erodes
most plants require a pH of ___
7
name 5 human impacts on soil
- acid rain
- people walking on soil
- fertilizer
- deforestation
- overgrazing
how does acid rain affect soil?
changes the pH of soil; washes away nutrients
how does walking on soil affect soil?
compresses space between soil particles; reducing air and water, killing plants
how does fertilizer affect soil?
changes the natural supply of nutrients; soil depends on fertilizer
how does deforestation affect soil?
the soil is exposed and erosion begins; the soil cannot sustain plant life
how does overgrazing affect soil?
the plant dies and soil is exposed
name 6 ways to minimize soil impact
- use less fossil fuels
- walk around soil
- crop rotation
- avoid clear cutting
- manage livestock effectively
- maintain ground cover