Fertilization is effective then, when fertilizer can; be taken up by the plant. Therefore, each fertilizer should be placed in the soil in the zone of hair roots. The location of these roots varies and depends not only on the type of root system, but on the type of soil, how to cover it, various elements of armament, etc.. When choosing the method of fertilization, one should remember, that not every component of a fertilizer mixture moves at the same rate through the soil. Nitrogen fertilizers reach the roots the fastest, slower potassium and very slowly phosphorus. In heavy soils, clayey, the movement of fertilizers is slower than in loose soils, sandy.
The surface fertilization is effective then, when fertilizer can be mixed with the surface layer of the soil or when it can be introduced into the soil by abundant watering. However, such opportunities are rarely found in green areas. Most often we have d,o dealing with surfaces that are sodded or covered with impermeable or semi-permeable surfaces.
The introduction of fertilizers through the pans around trees growing on the sidewalks is very ineffective, especially with insufficient watering. In older trees, the hair roots are located in a very remote zone. The surface fertilization by the turf of the lawn will primarily be the fertilization of the lawn, because shallow roots of grass plants will absorb these fertilizers the fastest. Under these conditions, methods of deep fertilization are the most effective. They consist in placing dry fertilizers in the soil in the depth holes 30-60 cm, spaced apart 60-100 cm, or pouring into the soil under pressure (injection) fertilizer solutions. The latter method is simpler and more effective, because the fertilizer can be taken immediately. For this purpose, larger sprayers can be used or special light vehicles with properly prepared tanks can be used.