Subject
isotope application
13
tracer technique
9
isotope geochemistry
6
plant soil relationship
4
soil physics
3
stable isotope
3
radioisotope
2
agricultural use
1
agriculture
1
autoradiography
1
climatic change
1
environment
1
isotope production
1
labeled compound
1
nitrogen cycle
1
paleoclimatology
1
plant metabolism
1
radioecology
1
soil science
1
weed
1