Do plants have preference for the form of nitrogen as nutrient?

Question

In the nitrogen cycle (ecology), it is usually described that plants can use nitrogen in the form of ammonium. Do plants prefer one form of nitrogen over the other?

Answer 1

Do plants have preference for the form of nitrogen as nutrient ?

Yes, plants do have preferences for the form of nitrogen(N) they take up, but this preference depends on species, soil conditions, and environmental factors.

Forms of Nitrogen Available to Plants

1.Nitrate( NO3-) - most mobile in soil.

2.Ammonium ( NH4+) - less mobile, can accumulate in acidic soils.

3.Urea /Organic N - must be converted to ammonium or Nitrate before use .

Plant preferences

-Many crop plants ( e.g; wheat, maize )prefer Nitrate (NO3-) because:

-highly soluble and easily transported in xylem.

-Some plants (e.g; rice, tea, potatoes) prefer Ammonium (NH4+), especially in flooded or acidic soils where

nitrate is less available.

-Legumes can use both , but they also fix atmospheric nitrogen via symbiotic bacteria.

Environmental Influence

Aerated soils ---> nitrate uptake dominates.

Waterlogged/ acidic soils ---> ammonium uptake dominates.

Balanced supply of both forms often gives the best growth, since nitrate uptake raises rhizosphere pH and ammonium lowers it ----> together they stabilize root environment.

Thus plants do have preferences ---- some are nitrate - loving, some are ammonium - loving, but most grow best when both forms are present in balance.