Essential Nutrients in Agricultural Systems
Plant growth and ultimately agricultural productivity depends on a relatively small group of essential elements working together in balance. Carbon (C), hydrogen (H) and oxygen (O) are supplied by air and water and make up most of plant material. The remaining nutrients are derived from the soil and are critical to how crops grow and perform.
These soil-derived nutrients are grouped by how much plants require. Nitrogen (N), phosphorus (P) and potassium (K) are the primary macronutrients, needed in the largest amounts and most likely to limit production. Calcium (Ca), magnesium (Mg) and sulphur (S) are secondary macronutrients, also essential, but typically less limiting, although their importance has increased in modern systems.
Micronutrients, including manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), iron (Fe), chlorine (Cl) and nickel (Ni), are required in much smaller quantities but remain vital for plant function. Some other elements, such as silicon (Si) and sodium (Na), may be present in significant amounts and can influence growth, but are not universally essential. In addition to plant-essential nutrients, animals also require elements such as sodium (Na), selenium (Se), cobalt (Co) and iodine (I), which are typically supplied through forage or supplementation.
The presence of nutrients in soil does not guarantee plant uptake. Soil pH is a key factor, influencing both availability and potential toxicity of different elements. This is further shaped by soil type, organic matter, drainage and biological activity, all of which affect how nutrients behave in practice.
