EE19-Soil Flashcards
what are the physical properties of soil?
crumb structure coherance - ability to form ball elasticity porosity permeability
What are soil groups determined by?
temperature and rainfall
What is humus?
dark organic material that forms from soil when animal matter decays
What are the 3 main nitrogen types in soil?
ammonia NH3
Nitrate N03-
Nitrite No2-
What are the levels of gasses in soil ‘atmosphere’?
same nitrogen
10-100x more CO2
less O2
in waterlogged - increased methane, ethylene, amonia and hydrogen sulfide.
What are soil profiles dependent on?
parental material climate living organims topography=surface structure duration of pedogenesis (age) (evo of soil)
What are the hydrologic soil groups based on?
run off potential
What are the 3 British soil types?
Podzol acid -soils high rainfall
Brown Earth - fertile soils
Chernozean - calcerous soils, low rain
What are soil groups influenced by?
water availability
temperature
geology -ph
What is a soil horizon?
layer parrallel to soil surface whose physical characteristics differ from those above and beneath
What is the cation exchange capacity of soil?
total no. of cations (+) that can be absorbed per unit weight of soil.
-exhibited by minerals, organic clay and humus
What do plants require in addition to H O C N?
P- nucleic acids ATP K- enzyme activation S - protein coenzymes Ca - membrane messages Mg - chlorophyl CaPS MgK
What are the 8 other micronutrients that plants require?
Fe - enzymes and chlorophyl Cl - photosynthesis Mn - enzymes B - Carbohydrate transport Zn - enzyme activation Cu - redox enzymes, electrons Mo - nitrogen metabolism Ni- nirtogen metabolism MnZn CuB MoNi FeCl CuZnNi = toxic at high levels
What are Calcicoles?
lime lovers, plants characteric of chalk/limestone soils
What are Calcifuges?
lime avoiders, plants characterised in soils low on calcium.
What does Calcium do in plants?
- neutralises acids
- alters pH values
- many physiological effects - catalyst ion uptake, membrane.
- Affects soil conditions.
- humification, soil formation ands structure
Why are soils important?
Soils determine the identity of the the dominant plant species.
Soil nutrient supply determines the net primary productivity
Soil pH influences soil chemistry, biology and resource availability.
