Agriculture & Biology
urea fertilizers
72%
environmental assessment
63%
cattle manure
60%
fertilizer application
50%
animal manures
49%
climate
36%
corn
32%
production technology
16%
runoff
14%
mineral fertilizers
13%
Great Plains region
10%
cattle finishing
9%
stover
8%
nitrous oxide
7%
greenhouse gas emissions
7%
fossils
6%
environmental impact
6%
clay
6%
life cycle (organisms)
5%
ammonia
5%
livestock
5%
urea
5%
phosphorus
4%
farms
4%
carbon
4%
nutrients
3%
energy
3%
nitrogen
3%
Earth & Environmental Sciences
environmental assessment
56%
urea
53%
cattle
52%
manure
50%
maize
46%
fertilizer
45%
plain
40%
production system
20%
simulation
11%
runoff
9%
nutrient loss
8%
energy use
6%
nitrous oxide
6%
livestock
6%
field experiment
5%
greenhouse gas emissions
5%
farm
5%
life cycle
5%
ammonia
5%
environmental impact
5%
methane
5%
fossil
4%
phosphorus
4%
nitrogen
3%
carbon
3%
loss
3%
trend
3%
comparison
2%
material
2%
rate
2%
analysis
1%
Medicine & Life Sciences
Manure
85%
Fertilizers
81%
Zea mays
65%
Climate
52%
Urea
49%
Cattle
42%
Fertilization
14%
Greenhouse Gases
11%
Clay
9%
Methane
9%
Livestock
8%
Nitrous Oxide
7%
Farms
7%
Ammonia
7%
Life Cycle Stages
7%
Phosphorus
6%
Carbon
6%
Nitrogen
6%
Nutrients
5%
Engineering & Materials Science
Urea fertilizers
100%
Manures
74%
Runoff
18%
Fertilizers
16%
Nutrients
8%
Urea
8%
Phosphorus
7%
Ammonia
6%
Gas emissions
6%
Greenhouse gases
6%
Clay
6%
Farms
6%
Environmental impact
6%
Methane
6%
Nitrogen
6%
Life cycle
5%
Oxides
5%
Carbon
4%
Experiments
2%