Important N Species NH 3 ammoniagas, volitization NH 4 - ammoniumatmospheric form of NH3, nutrient N 2 H 4 hydrazinecarcinogenic, rocket fuel NH 2 0HHydroxylamineamines, opiotes N 2 dinitrogen atmospheric N N 2 Onitrous oxidebrown cloud, greenhouse gas, denitrification NOnitric oxidetailpipe emissions, smog HNO 3 nitric Acidenergy emissions NO 3 - nitratenutrient, acidification
Problems With NH 3 Volatilization Acid Atmospheric Deposition raises pH of rainwater, more SO 2 dissolves ammonium sulfate forms - oxidizes soil releases sulfuric & nitric acid Eutrophication water and land Loss of N to farmers Lowers N:P
Sources of NH 3 on Livestock Farms Manure Application Animal Housing Manure Storage Grazing Fertilizer Application Crops Descending Order of Importance Bussink & Oenema, 1998
Relative to carbon dioxide the other greenhouse gases together comprise about 27.63% of the greenhouse effect (ignoring water vapor) but only about 0.56% of total greenhouse gas concentrations. Put another way, as a group methane, nitrous oxide (N2O), and CFC's and other miscellaneous gases are about 50 times more potent than CO2 300x more active than CO 2
Immobilization/Assimilation Incorporation of inorganic N to organic N Plants/microbes can use only inorganic N (NH4 and N O3) to produce organic matter However, new evidence suggests “tasty” organic N (primarily amino acids) can be utilized by plants/microbes.
LEAKY FAUCET HYPOTHESIS Persistent “leak” of DON from catchments DON is decoupled from microbial demand for N. DON export coupled to soil standing stock of C, N Lag between N inputs and DON export