Macronutrient - Nitrogen (N) is a vital element for the growth of plants. Nitrogen is used in fairly high amounts by plants during the growing season for vegetative growth. It contributes to the chlorophyll molecule which is vital for photosynthesis.  Since it is highly water soluble, nitrogen moves through the soils rather quickly and is lost to the plants. That is why it needs to be applied each growing season.

Sources - The main source of nitrogen for home landscapes will be either granular or water soluble fertilizer. Other sources include organic matter, nodules from legumes and the atmosphere.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.