Good nutrient management is essential for promoting healthy, nutrient-rich crops, farm profitability and protecting the environment.
Crops require 17 essential minerals for optimal plant growth. These can be found in the soil and are called macronutrients in high amounts, or micronutrients in very small quantities.
What are micronutrients?
These are just as important as macronutrients and if any are absent from the soil, or are not adequately balanced, it can cause crop failure and abnormalities. Micronutrients that crops require include:
Micronutrients play an important role in plant growth, development, reproduction, and metabolism, including photosynthesis and respiration.
Understanding micronutrient deficiency in crops
In recent years, micronutrient deficiency in soil, and therefore crops, has become more common due to:
- High-yield crops remove micronutrients from the soil.
• Increased use of NPK (Nitrogen, Phosphorus and Potassium) fertilisers without the inclusion of micronutrients.
• Progressive fertiliser technology results in less residual addition of micronutrients.
• High soil erosion.
Micronutrient deficiency can affect not only plant growth, but also crops’ nutritional content and, in turn, human health.
In many countries, particularly developing ones, mineral deficiency in edible grains, known as ‘hidden hunger’, has become a big health problem.
Crop micronutrient deficiency testing and treatment
Thanks to soil and plant analysis, farmers can test for any micronutrient deficiencies that may be affecting their crops.
The results allow them to determine which nutrients are not being provided by the soil and which fertilisers, containing the necessary micronutrients, need to be applied to improve crop quality and productivity.
In turn, this information helps them protect the environment from over-fertilisation, which can result in water contamination.
Copper and zinc micronutrient deficiency
In the UK, copper and zinc are two trace elements commonly lacking in the soil.
Copper deficiency can lead to stunted plant growth, discoloured leaves and sterile pollen, which in turn causes poor grain formation and results in a poor yield.
Zinc is important for good early plant development and a high yield. A deficiency of it leads to fewer grains per ear, poorer grain quality and pale leaves.
Micronutrient seed treatment
In crop plants, fertilisers containing micronutrients can be applied to the soil, sprayed directly onto leaves, or added as seed treatments.
Seeds can be treated with micronutrients by either soaking them in a nutrient solution of the correct strength for a specified time, or by coating them with micronutrients.
Research comparing micronutrient seed treatment with soil and foliar applications found it ‘performed better or similar to other application methods’ and was ‘easy and cost effective’.
Benefits of micronutrient seed treatment
The benefits of micronutrient seed treatment are:
- Less is required so more cost-effective
• Easy to apply
• Improves seedling emergence
• Healthier root growth
• Vigorous plant growth
• Increased yield potential
• Grain micronutrient enrichment