The most quickly available source of nitrogen to plants is Nitrate fertilizers.

Nitrogen is one of the essential nutrients required by plants for their growth and development. It is a major component of amino acids, proteins, nucleic acids, and chlorophyll. However, nitrogen in its elemental form (N2) is not readily available to plants as they cannot directly use it. They rely on different forms of nitrogen compounds to meet their nitrogen requirements.

Nitrate fertilizers are a commonly used source of nitrogen in agriculture. These fertilizers contain nitrogen in the form of nitrates (NO3-). Nitrate is an oxidized form of nitrogen and is readily available for plant uptake.

Reasons why Nitrate fertilizers are the most quickly available source of nitrogen to plants:

1. Water-solubility: Nitrate fertilizers are highly water-soluble, which means they dissolve easily in soil water. This solubility allows the nitrates to move freely with the soil water and reach the plant roots, making them readily available for uptake.

2. Plant uptake: Plants have specialized transporters on their root surfaces that facilitate the uptake of nitrate ions. These transporters actively transport nitrate ions into the plant roots, ensuring rapid and efficient absorption of nitrogen.

3. Conversion to amino acids: Once inside the plant, nitrate ions are converted into amino acids, which are then used to synthesize proteins and other nitrogen-containing compounds. This conversion process is relatively quick, allowing plants to utilize the nitrogen from nitrate fertilizers efficiently.

4. Minimal leaching: Nitrate ions are negatively charged and do not bind strongly to soil particles. As a result, they are prone to leaching, which means they can move downwards through the soil profile with water. This leaching can be advantageous as it helps to prevent nitrogen buildup in the soil, ensuring a continuous supply of nitrogen to plants.

In conclusion, nitrate fertilizers are the most quickly available source of nitrogen to plants due to their water-solubility, efficient plant uptake, rapid conversion to amino acids, and minimal leaching potential. Farmers and gardeners often use nitrate fertilizers to provide an immediate nitrogen boost to plants and promote healthy growth.