Questions Flashcards
Which three soil properties control available water?
- Pore sizes
- Structure
- Organic matter
What is porosity and how does the structure influence this?
- Porosity is the pore space in soil between mineral particles (and solid organic matter) filled with either air or water.
- Soil structure influences porosity because porosity depends on the size of the pores and soil structure includes the size of the pores.
How are gley soils formed?
Gleying: saturation of the soil pores with water, leading to grey and/or red-brownish colourations.
How are podzols formed?
chemical and physical processes of leaching transport, and precipitation of humus with iron and/or aluminium.
Why is it important to know a soil’s pH?
Soil pH affects the number of nutrients and chemicals that are soluble in soil water, and therefore the amount of nutrients available to plants.
What are the jobs of different bacteria?
- Decomposers: decomposition of organic material when moister levels are high.
- Nitrogen fixers: Fix nitrogen in the soil by inoculating legume seeds.
- Disease suppressors: disease suppression.
- Aerobes and anaerobes: produce toxic compounds that limit root growth and cause root diseases. 5. Actinobacteria: breaking down humates and humic acids in soils.
- Sulfur oxidizers: convert sulfides into sulfates
What is the relation between soil biology and SOM?
Soil organic matter plays a vital part in enhancing soil fertility and quality
How to increase soil health?
Limit disturbance
Keep it covered
Increase diversity
Keep a live root
Limit pesticides
Address compaction
Implement strategic grazing
What are the factors of land formation?
Weathering starts and bedrock starts to disintegrate
Organic matter disintegrates
Water percolates horizons form
A deeper profile is created, more humus, and a thicker horizon
What are the soil components?
Pore space:
20-30% water
20-30% air (gasses)
Soil solid:
45% minerals
5% organic matter
Explain the chemical and biological processes in soil formation and degradation
Chemical:
Transport of primary to secondary minerals
Chemically different
Biological:
Impact of Soil organisms
Tree roots growth in cracks
Name and give characteristics of four factors related to soil degradation
- Gleying: saturation of pores with water -> colouration
- podolization: the chemical and physical process of leaching
- browning: chemical and biological process in sandy soils with create erosion of iron -
> rusty colouring - Clay redistribution: chemical and physical mobilization transport and precipitating of clay