Drought is becoming an increasingly serious challenge for farmers across different regions. Climate change is bringing more unpredictable weather patterns, while dry periods are becoming longer and more severe.

Moisture deficiency is not only a source of physical stress but also disrupts physiological processes in plants. An adequate supply of macro- and micronutrients in the right proportions helps plants better prepare for drought and minimize its effects.

It is impossible to determine “by eye” or based solely on yield what nutrients are actually lacking in the soil. Only laboratory soil analysis can show how much of each nutrient is available to plants. Applying fertilizers without this information may be ineffective.

Key Nutrients Responsible for Plant Drought Tolerance

Potassium (K). Potassium is the main regulator of plant water balance. It controls the opening and closing of stomata — microscopic pores on leaves through which water is lost through transpiration. Under drought conditions, an adequate potassium supply allows stomata to close more quickly, minimizing moisture loss. Potassium also accumulates in cells, increasing their osmotic pressure. This helps cells maintain turgor and prevents wilting, while also enabling roots to absorb water from the soil even when its availability is low.

Boron (B). Boron is essential for the formation and strength of cell walls. It also affects carbohydrate transport, ensuring their movement to the roots. The root system requires energy for growth and functioning, which is critical for water uptake.

Copper (Cu). As a component of enzymes, copper helps protect cells from oxidative stress. Copper also contributes to lignin synthesis — a substance that strengthens cell walls and the vascular tissues responsible for water transport, helping plants maintain their structure under dehydration.

Zinc (Zn). Zinc affects the synthesis of auxins — growth hormones responsible for root system development. Therefore, adequate zinc nutrition promotes the formation of well-developed roots, which are a key factor in water uptake.

Other nutrients also indirectly contribute to crop drought tolerance through their roles in plant growth and physiological processes.

Phosphorus (P). Phosphorus is critical for root system development. An adequate supply of this nutrient promotes the formation of strong and deep roots capable of reaching moisture in lower soil layers that may be inaccessible to a weak root system. This is particularly important during prolonged periods of drought.

Nitrogen (N). Nitrogen has a dual effect on drought tolerance. On the one hand, an adequate nitrogen supply is essential for the synthesis of proteins, enzymes, and chlorophyll, supporting plant growth and functioning. On the other hand, excessive nitrogen stimulates vigorous vegetative growth, which can make plants more vulnerable to drought.

Calcium (Ca). Calcium strengthens cell walls and increases their resistance to deformation during water loss, allowing tissues to function under low turgor conditions. Calcium also participates in intracellular signaling, activating appropriate protective responses.

Magnesium (Mg). As the central component of chlorophyll, magnesium enables plants to maintain efficient photosynthesis when supplied at adequate levels.

Sulfur (S). Sulfur is a component of amino acids involved in the synthesis of antioxidants that neutralize free radicals produced in plant tissues during drought..

Iron (Fe). Iron deficiency causes chlorosis, reduces photosynthesis, and increases plant vulnerability to stresses, including moisture deficiency.

Manganese (Mn). Manganese increases the water-holding capacity of plant tissues, reduces transpiration, and is involved in enzymes that neutralize toxic compounds.

Thus, each nutrient plays a role in building plant resilience, and mineral nutrition can be a powerful tool in managing drought stress. However, for this tool to be effective, it must be used strategically. Applying fertilizers “blindly” may fail to deliver the desired result and can even be counterproductive.

How can this be addressed? Conduct a soil analysis. This allows you to:

• Identify deficiencies: determine which specific nutrients are lacking to support plant water balance and root system development.
• Balance crop nutrition: select the appropriate fertilizer composition and adjust application rates to provide the plant with a complete set of nutrients needed for its protective mechanisms.
• Allocate resources efficiently: avoid spending money on nutrients that are already sufficiently available in the soil and focus on those that actually need to be applied.

If you are dealing with the effects of drought every year, it is time to change your approach! Start with soil analysis — it is the first step toward understanding what is actually preventing your fields from reaching their full potential. The team of specialists at AgriLab can help.