THE ROLE OF LEAF NUTRIENT ANALYSIS IN CROP MANAGEMENT OF SUBTROPICAL PERENNIAL CROPS
Subtropical perennial crops, such as mangoes and avocados, are vital to global agriculture, supplying food, fibre, and economic stability. These crops have unique nutritional needs that change throughout their extended growth cycles. Effective nutrient management ensures optimal growth, quality, and resilience against environmental stressors.
Leaf nutrient analysis provides valuable insights into a plant’s nutrient status, revealing deficiencies or imbalances before they affect yields. Unlike visual symptoms, which often appear too late for effective correction, early detection through leaf analysis enables timely interventions that can prevent crop loss and improve overall plant health.
Benefits of leaf nutrient analysis
- Early detection of nutrient deficiencies
Leaf analysis serves as an early warning system for nutrient imbalances that may not be visible in the field. Addressing these issues before they impact growth and yield ensures a more productive crop cycle.
. - Optimised fertiliser use
By tailoring fertiliser applications based on leaf analysis results, producers can reduce waste, lower costs, and minimise environmental impacts. This precision approach ensures that crops receive the right nutrients in the right amounts.
. - Enhanced fruit quality and marketability
Proper nutrient management directly influences the size, colour, flavour, and nutritional value of the fruit. Meeting consumer demands for high-quality produce starts with maintaining a balanced nutrient profile in the plant.
. - Improved Crop Resilience
Nutrient deficiencies weaken plants, making them more susceptible to diseases and environmental stresses. Regular leaf analysis helps farmers maintain crop health and productivity, even in challenging conditions.
. - Identification of environmental stressors
Leaf sampling can also detect issues such as soil pH imbalances, salt stress, and the presence of harmful elements like heavy metals. This allows for timely corrective measures to mitigate negative effects.
Best practices for leaf sampling
Leaf sampling, also known as foliar analysis, involves collecting leaves from plants to evaluate their nutrient content. To ensure accurate and useful results, it is essential to follow proper sampling procedures.
When to Sample
Leaf nutrient levels fluctuate with seasonal growth cycles, so timing is crucial. For mango trees, for example, the best sampling periods are:
- Summer: Shortly after harvest and before the first major vegetative flush.
- Winter: During the late autumn dormant period, before flowering. This is when nutrient levels are most stable and representative of the plant’s status.
If diagnosing an issue, collect leaves as soon as symptoms appear. When sampling outside the standard timeframe, take a second set of healthy leaves from nearby unaffected trees for comparison.
How to Collect Samples
To ensure consistency and reliability:
- Choose uniform sampling areas based on soil type, slope, variety, and irrigation design. Each area should not exceed five hectares.
- Collect leaves from the middle of the shoot, ensuring they are six to seven months old.
- Avoid collecting leaves from outer rows or trees at row ends.
- Sample at least four to five leaves from ten representative trees, creating a 40-50 leaf sample per block.
- Ensure leaves are healthy and free from visible nutrient deficiency symptoms. If testing a problem area, sample it separately and record its location for future reference.
Sending Samples for Analysis
Once collected, leaves should be placed in properly labelled sample bags and sent to an accredited laboratory. Advanced techniques such as inductively coupled plasma spectroscopy and ion chromatography are used to measure nutrient concentrations, providing accurate insights into the plant’s nutritional health.
Driving sustainability and profitability
Leaf nutrient analysis is a powerful tool for modern agriculture, bridging traditional farming practices with scientific insights. By incorporating this practice into regular crop management, farmers can make data-driven decisions that lead to healthier plants, higher yields, and more sustainable production systems.
As technology continues to advance, leaf nutrient analysis remains a cornerstone of efficient and environmentally responsible farming. By adopting this practice, producers can stay ahead in the competitive agricultural landscape while ensuring the long-term health of their crops and the land they cultivate.
For more information and recommendations for leaf sampling by crop type, read the full article in ROOTED magazine (Issue 5) at https://duroimultiplant.co.za/publications/