This is in accordance with ‘Liebig's law of the minimum’ – which states that plant growth is controlled not by the total amount of available nutrients, but by the nutrient in shortest supply. Increasing the amount of the limited nutrient will ultimately result in improved plant growth.
Nitrogen (N) is an essential element in all living systems. It is the nutrient which is often required in the greatest quantity by crops and is primarily responsible for stimulating vegetative growth.
Phosphorus (P) plays a role in photosynthesis, respiration, energy storage and transfer, cell division, cell enlargement and several other processes in plants.
Potassium (K) is an essential nutrient for plant growth. K regulates the plant’s water intake and loss, increases drought tolerance and plays a vital part in photosynthesis.
With today's emphasis on high crop yields, there is an increased need for Calcium, Magnesium and Sulphur.
Calcium (Ca) is perhaps the most important secondary nutrient, necessary for the proper functioning of growing points, particularly root tips. Ca forms compounds that strengthen cell walls, helping to reduce bruising and disease in fruit and vegetable crops.
Magnesium (Mg) is the only mineral constituent of the chlorophyll molecule and, as such, is vital for optimum photosynthetic activity and the enzymes that support plant growth.
Sulphur (S) is an essential part of many amino acids and proteins.
Micronutrients are as important to balanced plant nutrition as primary and secondary nutrients, though plants don't require as much of them. They reinforce and supplement the strong plant growth and structures provided by major and secondary nutrients. A lack of any one particular micronutrient in the soil can limit growth, even when all other nutrients are present in adequate amounts.
Micronutrients include Boron (B), Copper (Cu), Iron (Fe), Manganese (Mn), Molybdenum (Mo), Zinc (Zn), and Chloride (Cl).
Soil and climatic conditions can limit a plant’s uptake of nutrients at key growth stages. Nutrients can also be lost from the soil by various processes. To obtain a reliable assessment, a soil test followed by the appropriate plant/leaf analysis is recommended.