California Citrus Newsletter

February 2023


Not all nitrogen forms are the same - and your N choice has a great impact on your citrus trees' potential

Having a strong, balanced nutrition program is important when growing any agricultural crop. Providing all essential nutrients when the crop demands them is critical in order to achieve high yields, quality, and profitability. A balanced nutrition program will also ensure that you maintain overall tree and soil health. Keeping the 4R’s of Nutrient Stewardship in mind will also help to ensure the greatest crop yield and profitability with the least amount of environmental impact.

Now a little agronomic knowledge -- We are often told that 1 lb N = 1 lb N = 1 lb N and that all N sources are essentially equal. While all forms of nitrogen do supply nitrogen, they have different effects in the soil and in the plant, and these effects make all the difference! Choosing a fertilizer with an available form of nitrogen is critical to your citrus crop program this time of the year.

Most agricultural nitrogen fertilizers consist of one or more of the following forms of nitrogen:

  • Urea
  • Ammonium
  • Nitrate
Soil temperature (°F) Time for conversion (weeks)
40 6+
50 2+
75 1+

Vismeier and Amberger, 1980

Nitrate is the preferred form of nitrogen for almost all agricultural crops. Ammonium and urea do supply nitrogen, but these forms must be converted to nitrate before they are available to the plant. These are biological processes that must occur and are affected by many factors such as soil temperature, soil moisture, and soil pH. Something to consider, especially in the cooler spring months, is that cold soils slow ammonium conversion to nitrate. This means that it can take more than two weeks for ammonium to convert to nitrate when soils are around 50°F. In addition to soil temperature, extremely wet or dry soils can also slow the conversion of ammonium to nitrate. Acid soils also contribute to a slower conversion. Nitrate nitrogen from calcium nitrate is immediately available to the crop and promotes balanced nutrition by promoting the uptake of cations such as calcium, magnesium, and potassium.

amonium vs nitrate - cation uptake.png

Nitrate promotes cation uptake graph.png


Consider adding YaraLiva Calcium Nitrate to your citrus crop nutrition program this season

YaraLiva® CN-9®

10-20 gallons per acre per application is ideal, especially for the first soil-applied application in the spring. Depending on your variety and most recent tissue analysis, 50% of your annual N should be applied in February and March (weekly or bi-weekly). Then, 25% in April and 25% in May and June.

Refer to your most recent analytical soil-leaf tissue reports and a Yara Agronomist to help you put together a more targeted and efficient citrus crop program.

For a dry spreadable calcium nitrate product, choose YaraLiva® TROPICOTE®.

YaraLiva Calcium Nitrate products provide 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 and health for efficient water and nutrient uptake, and salinity management

crop stages image.png


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

Vanessa Vicencio

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


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