Nitrogen Use Efficiency, Nitrogen Fertilizers, NUE, Nitrogen and the EnvironmentNitrogen Cycle

Nitrogen Cycle NUENitrogen Cycle NinjaLightning, Nitrogen

N Cycle
N Cycle Animated
N Cycle, Dr. Robert Mullen
N Cycle (dial)

NASA, Global Warming (current CO2 level)
We do not have a "companion earth" to test this against.
We have to get it right the first time. 
Bumper Sticker, Nitrogen Cycle and Global Warming
407CO2 Nitrogen Cycle and Global Warming  Amber_CO2 Glenn_Garcia  Global Warming CO2 413 CarBurnDioxide    Nitrogen Cycle Simplified  Green_Kezar  Austin  Alserae  Electric Cars How big is your footprint  Joao CO2 Michaela

Nitrogen Cycle Poem (2014)
N metabolism, plant N loss
Oklahoma State University, NUE Raun et al. (1997). Nitrogen cycle ninja, a teaching exercise. J. Nat. Resour. Life Sci. Educ. 26:39-42 (pdf)
Carbon-Nitrogen Cycles, SOIL 5813 Class

FACTS

2015, USA  (source USDA ISSN 1949-1522)
Population 323 million
Cattle Inventory 95 million
acres
Corn 88.9 million
Soybean 85.1 million
Wheat 56.1 million
Cotton 9.0 million

World Nitrogen Use Efficiency for Cereal Production is 33%,
Agronomy Journal 91:357

NITROGEN Publications from Oklahoma State University