Essential Plant Nutrients
Carbon (C), Oxygen (O), Hydrogen(H)
Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulphur (S)
Boron (B), Chlorine (Cl), Copper (Cu), Iron (Fe), Manganese (Mn), Molybdenum (Mo), Nickel (Ni), Zinc (Zn)
Symptoms and their interpretation
Plants have their mechanism to express nutrient requirements by showing "symptoms" of deficiency or toxicity (over-feeding). In a sense, this is a plant's voice or body language that can even reveal to us which mineral is deficient. Many a times, similar symptom may occur due to deficiency of more than one essential elements. In such a case, observing, if the symptom first appeared in newer leaves and shoots or the older ones, can help in identifying the true cause of deficiency. This happens because some of the elements are mobile, meaning they can move from one part of the plant to another whilst the others are immobile.
- Mobile elements: N, P, K, Cl, Mg, Mo. If the mineral element is mobile, it's deficiency/toxicity appears in the older part of the plant first. This is because the nutrients travel from older leaves to the newer leaves where they are needed most.
- Immobile elements: S, B, Fe, Zn, Ca, Cu, Mn, Ni. If the mineral element is immobile, the nutrients can not move from the older to the newer leaves. Therefore, deficiency symptoms appear in the growing region of the plant first.
Signs/Symptoms of Different Nutrient Deficiencies
Leaves & stems of Phosphorus deficient plants are generally dark green. Older leaves turn yellowish with a pink/purplish margin.
Growing young leaves become yellow, and the terminal growing region dies. Additionally, we can see dark brown and irregular spots on the plants in case of severe deficiency.
Inter-veinal chlorosis, especially midway between the leaf margin and midrib. Plants with Zinc deficiency experiences severely stunted growth as Zinc helps in elongation of internodes, which will be affected. At critical stages, plant tissue becomes grey-white and eventually dies.