Fertilizer is a material, usually organic, that is added to soil to provide nutrients for plants. The three primary nutrients in fertilizer are nitrogen, phosphorus, and potassium. Fertilizer can be applied in several ways, including sprinkling it on top of the soil.
The main advantage of applying fertilizer by sprinkling it on top of the soil is convenience. It is much easier to simply sprinkle fertilizer on top of the soil than it is to dig trenches or holes and then bury the fertilizer in them. Also, if you have a small garden area, applying fertilizer by hand may be the only practical option.
However, there are some disadvantages to sprinkling fertilizer on top of the soil as well. One is that unless the granules are very small, they will not evenly distribute themselves and will tend to fall off to one side or clump together. This can result in areas of your garden getting too much or too little fertilizer. Another disadvantage is that if it rains soon after you apply the fertilizer, some of it may wash away before it has a chance to be absorbed by plant roots.