The element absorbed both in cation and anion form is
A
Sulphur<br>
B
Nitrogen<br>
C
Calcium
D
Phosphorus
Correct Answer: Nitrogen<br>
Nitrogen, required in large quantities for healthy plant growth, is supplied either as a cation (ammonium - NH4+) or an anion (nitrate - NO3-). The ratio of these two forms of nitrogen in the nutrient solution can have large effects on both the rate and direction of pH changes with time.