December 2020

Macronutrient deficiencies symptoms

The deficiency symptoms of macronutrients are wide and have different severity according to various‑related factors.

Each crop has a specific susceptibility to lack or scarcity of one or more nutrients and the negative effects, which not always are immediately and easily visible, have sure effect on the metabolic pathways.

Nitrogen

The main deficiency symptoms are lack or stunted growth of plant, leaves and fruits, yellowing and falling of the leaves (the first symptoms are visible on the older leaves) and purplish coloration due to accumulation of pigments such as anthocyanin.

The symptoms can be more severe in case of reduced presence of organic matter in the soil and high carbon residues (straw) onto soils.

In plant physiology, Nitrogen is essential for the synthesis of nucleic acids, coenzymes, amino acids and proteins, chlorophyll and ATP.

Phosphorus

The main deficiency symptoms are reduced rooting and flowering, production of dark-green leaves, reddening or yellowing of leaf margins and necrosis of older leaves, reduced tillering in cereals and storage potential on various horticulture crops and fruits.

The symptoms can be more severe in case of reduced presence of organic matter in the soil, soil with extreme conditions of pH (acidic or very alkaline), low temperature and wet conditions, high Calcium concentration.

In plant physiology, Phosphorous is crucial for energy transferring, synthesis of nucleic acids and protein and in several components of the cell membrane.

Potassium

The main deficiency symptoms are mottled chlorosis and necrosis (especially at tips and margins between veins and in older leaves), weak stalks in cereals and reduced ripening in fruits.

The symptoms can be more severe in case of high rainfall combined with leaching and in clay soils.

In plant physiology, Potassium is involved in the enzymes and coenzymes activation, in protein synthesis, in stomata functioning and turgor potential.

A number of agronomic strategies can be implemented in order to manage and overcome these deficiencies, which need to be adapted according to crop, climate and a variety of external factors (type of agronomic management, etc).