GEOG 203 Lecture Notes - Lecture 10: Soil Structure, Biogeochemical Cycle, Sorption
7 Feb 2018
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Capacity of system to resist disturbance and recover is resilience. Input from and output to vegetation and atmosphere; soil storage and transformations of energy, water, nutrients and chemicals. Residence time is the mass divided by the flux. The calcium budget in a forest in southern england (more slowly released than nitrogen) 11 precipitation (input) and 11 in ground water loss (output) Relatively steady loss of calcium; varying in nitrogen (high in temperate deciduous and low in west coast) and little phosphorous. In undisturbed systems, cycling is tight with inputs and roughly equals outputs. In disturbed systems, cycling can be loose with outputs > inputs. Ease of loss generally n > k > ca > p. Base cations (ca, mg, k) on cation exchange complex (from clay and organic matter) Phosphorous (p) strongly absorbed on clays, fe-al oxides, hydroxides and. Nitrogen (n) has limited adsorption (as no3- anion in most systems)
