Nitrogen is one of the key nutrients required by the flora; however, it is also scarce in the topsoil of tropical rainforests. So how do the flora get their nitrogen-based nutrients? Decomposition of organic matter, such as animal tissues and dead plants, produces ammonia which then mixes with the soil to produce nitrites and nitrates. These compounds are then taken in as nutrients by the delicate roots of the flora. The remaining ammonia undergoes nitration and is released into the atmosphere. During the next rainfall, water containing nitrogen compounds pours down. (See illustration below).

   Because tropical topsoils are so thin, nutrient stocks must be held within the biomass (leaves, roots, etc). In fact, the plants themselves are the true nutrient reservoirs; when they die, they release nutrients to other plants nearby.