In citrus, managing nutrients effectively is a must for optimal production, especially in the era of citrus greening. Nutrients enhance plant growth, boost fruit quality, and increase a tree’s resilience to a variety of stresses. What allows a citrus grower to manage nutrients effectively? Soil sampling and leaf tissue analysis. These two tools allow us to see what nutrients are in the ground and what nutrients are being taken up by the tree, and Florida citrus growers should be using both to create the best citrus fertilization program possible. Over-fertilizing or under-fertilizing will both have negative effects on yield. Thankfully, the experts at UF/IFAS have shared tips on using both soil sampling and leaf tissue analysis.
Tips for Soil Sampling
Soil testing can tell growers many things, including soil pH and salinity, the availability of essential macronutrients like potassium phosphorus, calcium, magnesium, and sulfur, and various micronutrients.
Tips for taking soil samples include:
- Take soil samples at least once a year, usually in late fall or early spring, before a new fertilization cycle.
- Conduct soil testing before planting to guide fertilizer applications in new groves.
- Split your grove into sampling areas that share features like soil type, management history, or crop performance.
- Soil samples should be taken using a soil probe or auger, and you want to go eight to ten inches of soil deep.
- For each soil sample in a given sampling area, take soil from five different places in the soil and combine to make up approximately one pint of soil.
- Mix the combined soil in a clean bucket and transfer to a labeled soil sample bag.
- Send the samples to a reputable laboratory for testing.
Tips for Leaf Tissue Analysis
Leaf tissue analysis tells growers the nutrient status of the plant at the time the samples were taken for nutrients like nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, zinc, manganese, iron, boron, and copper. The test lets growers know which nutrients are being taken up by the plant and at what levels; it’s important to ensure citrus trees are absorbing optimal nutrient levels for growth and fruit development and that nutrient levels are neither deficient nor toxic.
Tips for taking leaf samples for tissue analysis include:
- Use mature, non-fruiting spring flush leaves that are on growth that is 4 to 6 months old.
- Do not use immature leaves as their composition changes too quickly.
- Collect 20 to 30 leaves per sample area, complete with the petiole, or leafstalk.
- Do not collect leaves that are damaged, diseased, or dusty.
- Store collected leaves in a clean, labeled sample storage bag.
- Send the sample to a reputable laboratory as quickly as possible.
This column is sponsored by Griffin Fertilizer Co., and the opinions expressed herein may not reflect those of CFAN or of its advertisers.
BIO: Mike Roberts is the Vice President of the Frostproof, Fla.-based Griffin Fertilizer Co. Roberts joined the company in November 2011. He has spent the majority of his career in the fertilizer/agchem industry. Roberts earned a Bachelor of Science degree in citrus production from Florida Southern College in Lakeland. For more information, visit griffinfertilizer.com.