Subject
agriculture
13
plant breeding
5
forestry
4
nitrate
4
nutrition
4
agricultural use
3
fertilizer
3
forest decline
3
plant physiology
3
renewable energy source
3
crop
2
cultivated plant
2
denitrification
2
ecology
2
economics
2
erosion
2
nitrification
2
soil water
2
statistics
2
sustainable use
2
terpene
2
tree
2
water pollution
2
water protection
2
GMO ( genetically modified organism )
1
bean
1
biotope
1
cattle
1
cellulose
1
corn
1
drinking water contamination
1
economic aspect
1
ecosystem
1
energy crop
1
environmental impact assessment
1
environmental law
1
environmental policy
1
environmental protection
1
fertilization
1
fuel
1
geography
1
green genetic engineering
1
greenhouse
1
historical aspect
1
history
1
lysimeter
1
nitration
1
nitrogen cycle
1
pea
1
pest
1
more ...