Jeffry Hill is a professional agronomist and agriculture consultant who is an expert on soil and fertilization. Fungi, bacteria and many other microorganisms that live in the soil are mostly made of nitrogen and carbon. This is why these two nutrients are so important for the living soil. Nitrogen stands out for one simple reason: it is a gas that is constantly on the move. It rarely stays in one place and in one form for a significant amount of time because of the soil chemistry. Soils do have an electric charge. It is negative in most climates. Most soil nutrients have a positive charge, which makes the nutrients stick to the soil. Nitrogen, on the other hand, has a negative charge just like the soil. This is why it can’t stick to the soil. Instead, it leaves the soil rapidly whenever it can, mostly with water. When the water drains out, nitrogen is gone forever. The quicker your soil dries after the rain, the sooner you lose nitrogen. To cope with nitrogen losses, you should be adding it exactly at the time when plants need it most. This usually happens during their fast growth periods. Sandy soils that can’t hold on to water because of their structure are known to suffer from the loss of nitrogen. Adding nitrogen two or three times instead of a one big dose helps prevent its loss and build a sustained supply of this essential nutrient. Since nitrogen leaches easily with water, you never want to add it right before the rain. Nitrogen can also easily escape through organic matter, which is why you always should cover compost and manure before adding nitrogen, notes Jeffry Hill.