1 Subjects: “...nitrogen use efficiency...”

2 Subjects: “...carbon and nitrogen stable isotope ratios...”

3 Subjects: “...photosynthetic nitrogen use-efficiency...”

4 Subjects: “...nitrogen dioxide...”

5 Subjects: “...leaf nitrogen monitoring...”

6 Subjects: “...nitrogen...”

7 Subjects: “...nitrogen...”

8 Subjects: “...nitrogen...”

9 Subjects: “...nitrogen...”

10 Subjects: “...ammonia nitrogen...”

11 Subjects: “...migration of nitrogen forms...”

12 Subjects: “...nitrogen...”