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Geoecology
soils/biomes
Question | Answer |
---|---|
soil | a layer of natural materials on the earth's surface that is capable of supporting plant growth |
compositon of soil | 25% air 25% water 45% mineral matter 5% organic matter |
sandy soils | Large particles, some silt/clay, large pores, water drain freely. |
silty soils | between clay and sand, quite fertile, smaller pore, when wet heavy/poorly drained |
clay soils | small particles/stick together, waterlogged, sticky, very sticky, difficult to cultivate |
loam soils | perfect soil, roughly equal sand,silt,clay. retains some moisture, free drained, very fertile |
crumb structure | small, rounded grains, near surface, excellent for drainage and air movement |
platy structure | thin, flat particles, overlap, compacted soil, impede roots, hold up movement of water |
blocky structure | cube shaped particles, fit together, few pore spaces |
low ph (below7) | acidic soil, heavily leached, lack minerals, usually infertile |
neutral soils | PH level of 7 |
high ph (above7) | limey/high levels of calcium, develop on chalk or limestone region/desert or drought |
humus | organic matter in soils that is formed from decaying organic matter such as fallen leaves, grasses, animal waste etc. |
humus contrent | micro-organisms break down organic matter. makes soil look dark brown/black, reduce soil erosion, rich in nutrients |
soil moisture | enables plant roots to recieve nutrients in solution, influenced bytexture and structure of the soil |
brown/black soil | lot of humus/ very fertile |
grey soils | 'washed out' humus/nutrients leached, poor drainage/waterlogged naturally infertile |
red soils | presence of iron oxide, develop in regions warm/moist/tropical/equatorial climate iron breaks down and rusts low in nutrients/organic matter |