Environment Many environmental factors affect the need for various nutrients. Higher concentrations of plants increase the competition for nutrients. The plant species also influences the need for fertilizers. Grasses use large amounts of nitrogen and potash and leaves smaller amounts available for the trees. Vegetables and bulbs use large amounts of phosphorus.
Soil type influences the amount of fertilizer needed.
In sandy soils, nutrients are leached, move quickly into and through the root zone. Clay soils have more ability to hold these nutrients until plants can absorb them. Younger, more vigorous trees use more nutrients than do older, slower growing trees. Fertilizers can be applied for several different reasons and desired effects. One reason may be to increase the growth of plants.