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t+i #ta+* h-it*=

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Nitrogen.levels in soil impacted by nitrogenreleases. agricultural fertilizers. fossil fuel combustion. occult nitrogen accretion

. nitrogen fom atmospheric sources. nitrogen saturation point

. point beyond which any nitrogen added tosoil vvial not be incorporated into organicmatter and will remain in mobile form

$?i i

^! \ Itt.. 'lt i;v *+-' {

I\ d} i' 'H

lr*y+J--*l-\ L'\ f^'! a't -\' bl;*-.t^l+ yn$

, -:tk$y pH 4-8.5 (bacteria pH 6-8; molds anygffiic)

- hiuenced by

a.microbial metabolic activity

b.time of the year I Rain leaches bases )c.climate I soil acidic

d.previous cropping history e.g. type of litterand fertilizer

- Well-drained soil ) well aerated

- lnfluenced by ) soil particle size

€t*atl particles ) more sealed voids )r+*se*ial respiration occur ) O, decline,*= a*d other gaseous metabolites increase

+ +**l

c/N Ratios ilN <rytffi 7Y'

. C/N of 20 or less results in loss ofsoluble nitrogen from the system. soil said to have reached its nitrogen

saturation pointunder this low

. C/N above 20ammonium and nitrate to biomass

=E- -_