Plants need soil because it contains 16 chemical elements that are essential to a plant’s growth. These chemical elements are categorized into mineral and non-mineral groups.
Plants typically develop by acquiring nutrients from the soil. Their capability to absorb nutrients depends on the soil’s nature. The factors that affect the amount of nutrients available to plants are soil texture and acidity.
Soil texture refers to the amount of organic matter, sand, silt and clay the soil contains, and it affects the soil’s retention of water and nutrients. Compared to sandy soils, clays and organic soils can keep a higher amount of water and nutrients. The best type of soil consists of equal parts of organic matter, sand, silt and clay.
Soil acidity, or soil pH, measures the acidity of soil, and this affects the accessibility of nutrients. Soils with low pH levels often have fewer macronutrients, whereas soils with high pH levels contain fewer micronutrients. Soils ranging from 6 to 6.5 pH usually have more readily available nutrients. However, ericaceous plants, such as heather, prefer more acidic soils, and some plants thrive in more alkaline soils. Some of the macronutrients plants need to obtain from soil include nitrogen, phosphorus, potassium, calcium and magnesium.