Triomes example – students have 56 small triangles. They find a key term of which there are 14 (bold and underlined). They then make a larger triangle composed of 4 small triangles, the three outer directly relate to the key term in the centre. See example below. Soils Provide anchorage A medium containing water and nutrients Important in natural and agricultural systems

Soils Provide anchorage A medium containing water and nutrients Important in natural and agricultural systems Clay Particles < 0.002mm Slow to drain Contain –ve charged particles attracting +ve charged nutrients

Sand Particles between mm Large pore space aids drainage Roots penetrate easily but nutrients often lost Air in soil Provides gases for aerobic respiration If absent leads to anaerobic respiration – leaving inorganic matter eg peat Has a higher content in sandy soils

Soil water Needed for physiological function of plants Essential to replace loss through transpiration Required to help absorb nutrients Detritivores Feed on dead organic matter Earthworms, millipedes, woodlice Make organic matter available for decomposers

Living organisms Plants - hold soil together; provide humus and nutrients Decomposers – bacteria and fungi Nitrogen-cycle- bacteria and mycorrhizal fungi Peds Crumb – small and rounded structure allowing good drainage and rot penetration Blocky – block like; associated with clay minerals Platy – large and flat with slow drainage and reduced aeration

Factors effecting soil fertility / productivity Aeration, soil texture and structure Water drainage, infiltration and retention pH and thermal capacity Soil texture analysis Assesses proportion of minerals of different size categories Can use soil sieves to separate Can use sedimentation to separate by size

Soil pH analysis Uses barium sulphate to help soil particles to settle Uses pH indicator paper Can use test kits and compare a range of colours Soil water content analysis Estimated by heating water to make soil evaporate Sample is heated for 24 hours at 100 degrees [(wet soil mass - dry soil mass)/wet soil mass] x 100

Soil organic matter Can be estimated by heating the soil to burn off organic matter Uses a crucible to heat to 500 degrees [(dry soil mass – burned soil mass)/dry soil mass] x 100 Soil triangle Used to compare proportions of sand, silt and clay Must always add up to 100%