Micronutrient deficiencies can be tricky to diagnose and treat. By knowing your soil type, considering crop requirements and the season, and supporting this knowledge with diagnostic tools and strategies, effective management is possible.

Key points

• Micronutrient deficiencies are best determined by looking at the overall situation: region, soil type, season, crop and past fertiliser management.
• Soil type is useful in deducing the risk of micronutrient deficiencies.
• Tissue testing is the best way to accurately diagnose a suspected micronutrient deficiency.
• When tissue testing, sample the appropriate tissues at the right time. Plant nutrient status varies according to the plant’s age, variety and weather conditions.
• The difference between deficient and adequate (or toxic) levels of some micronutrients can be very small.
• When applying fertiliser to treat a suspected deficiency, leave a strip untreated. Either a visual response or tissue testing can allow you to confirm whether the micronutrient was limiting.