Differences and Effects of Natural and Synthetic Fertilizers At the core of the growth and germination of plants lie the nutrients they receive from the soil. The nutrients required for growth are classified into two groupings, macronutirents and micronutrients. Macronutrients are those that are needed in very large amounts, and whose absence can do a great harm to the development of the plant life. These nutrients include calcium, nitrogen, phosphorus, and potassium, and are very sparse in most soils, making them the primary ingredients in most fertilizers.