The Nitrate Form Of Nitrogen

The nitrate form of nitrogen is highly mobile in the soil. The way in which you apply it will determine how long the plants will have access to it.

- Bill Kerr

Being a negatively charged particle (an anion), nitrate is repelled by the soil colloids, which are also negative. This ensures that it remains in the soil moisture, where it is readily available to be taken up by the plants.

Unfortunately, this also means it is easily leached by heavy rain or over-irrigation, and is transported beyond the root zone. It also ends up contaminating underground water and streams.

When transplanting seedlings, whether bare roots or in plugs, frequent light irrigations are applied to establish the plants. Seedling plugs have a different texture to that of soil, so moisture does not move readily from the soil into the plug by capillary action, and the seedlings are only safe once the roots penetrate the soil itself. Frequent light irrigation carries the nitrate deeper than the shallow root system of such seedlings.