California Citrus Newsletter

June 2022


Stay Ahead of Nutrient Deficiencies with Soil and Tissue Analyses

Visible symptoms of nutrient deficiencies in your citrus trees are never fun to find, but there are ways to avoid seeing these pop up throughout the season. Having a well-balanced nutritional program for your citrus is a great way to try and stay ahead of deficiency issues. Tissue analysis is a great tool for citrus growers to mitigate deficiency issues also, by helping detect problems and adjust fertilizer programs. Most times you won’t need to adjust your programs too dramatically from season to season, but it is always good to have tissue samples pulled at least once a year to be sure you have the most efficient program for your crop.

Leaf nutrient concentrations are a good indicator of the overall nutritional status of citrus trees. Tissue analysis can determine if the tree has a sufficient supply of essential nutrients. An analysis can confirm if there are any deficiencies, imbalances, or toxicities. Not all deficiencies will show up as visible symptoms, another reason why tissue analysis should be done at least once a year. Tissue samples have to be taken at the correct time of year because nutrient concentrations will change throughout the growing season. The best time to pull samples is sometime between July and August. Newly emerged leaves will have higher concentrations of nutrients versus leaves that have matured. These matured leaves will have more stable concentrations of each nutrient.

Another helpful tool that growers can utilize is having soil samples pulled and analyzed to see what the soil health is in their orchards. Soil analysis measures the organic matter, pH, and extractable nutrients in a soil. If your soil is in good shape, there is no need to pull samples more than once a year.

The most useful soil test in a citrus field is for pH. The reason for this is because a soil’s pH greatly influences the availability of nutrients. Many nutrient deficiencies can be avoided by simply maintaining soil pH between 6.0 and 6.5. Combining tools such as soil analysis and tissue analysis can help identify problems and build more effective, efficient citrus crop programs.

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Potassium deficiency in citrus

There are many nutrient deficiencies that may be visible throughout the season, especially as the crop matures through the summer. Potassium is a nutrient that is commonly deficient in both soils and plants. Leaf potassium levels should be at least 1.2 to 1.7% and even as high as 1.8 to 2.4%. Use your most current leaf analysis, along with soil analysis and historical crop production to determine potassium needs and crop requirements. A five-year study of foliar applied potassium nitrate 13-0-46 (KNO3) in ‘Sunburst’ Tangerine conducted by UF, IFAS found that 3 applications (Pre-Bloom = February, Post-Bloom = April and Summer = July/August) resulted in a greater number of larger fruits. Foliar rates applied were 25 pounds potassium nitrate in 125-250 gallons water per acre per application. The larger fruit correlated in increased yield (boxes per acre) and better price per box based on larger fruit size. Sunburst is typically harvested in November through January. Use of annual leaf analysis and foliar, fertigation and soil applied potassium can be an effective program in increasing fruit size, and most likely grower returns.

Potassium uptake by the tree/crop peaks from late spring thru early summer after fruit set and early sizing occurs. Root nutrient uptake coincides with favorable root growth conditions and increasing transpiration stream.

Typical Uptake Curve - Citrus

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New in the market: YaraTera® NITRAKAL™

YaraTera NITRAKAL 5-0-7 with 3.4% calcium provides a balanced formulation of nitrogen, potassium and calcium that are immediately available for uptake by vegetable crops, fruit, and nut trees. Nitrogen and potassium are essential to achieving high marketable yields, uniformity of ripening, and proper brix in fruits and vegetables. Calcium is vital for improving tree and vegetable crop quality, health, growth, firmness, and shelf-life. Calcium is key to good soil quality. Immediately available nitrate nitrogen and water-soluble calcium.

  • Nitrate nitrogen increases plant growth by enhancing the uptake of other essential nutrients such as calcium, magnesium, and potassium
  • Water-soluble calcium promotes proper cell division for larger fruit and less chance of disorders such as creasing
  • Readily available calcium promotes root growth for efficient water and nutrient uptake

Add YaraTera NITRAKAL to your citrus fertilizer program.


Contact your local Yara representative to find a YaraTera NITRAKAL distributor near you.

Vanessa Vicencio

Sales Agronomist at Yara North America - South Central Valley, California



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