Agriculture & Biology
biological soil crusts
100%
nitrogen compounds
78%
arid lands
70%
denitrification
31%
soil fertility
24%
wet deposition
21%
dry deposition
21%
nitrogen cycle
17%
ammonium nitrate
14%
topsoil
14%
arid zones
13%
deserts
12%
bioactive properties
11%
ammonia
10%
oxidation
9%
nitrogen
7%
soil
6%
water
5%
Earth & Environmental Sciences
soil crust
87%
arid land
84%
fixation
50%
fertility
27%
denitrification
23%
nitrogen
15%
soil cover
15%
wet deposition
15%
ammonium nitrate
14%
dry deposition
14%
biological activity
13%
arid region
13%
limiting factor
13%
rate
12%
topsoil
12%
respiration
11%
desert
10%
ammonia
10%
oxidation
8%
water
3%
Medicine & Life Sciences
Soil
70%
Nitrogen Fixation
67%
Denitrification
35%
Nitrogen
21%
ammonium nitrate
19%
Ammonia
12%
Contraception
11%
Fertility
10%
Respiration
9%
Water
7%
Population
4%