Young Tree Nitrogen Fertilization

In attempts to incorporate varying media within the website, here is my first go at using Google Hangouts to LiveCast a presentation. The recorded presentation below provides nitrogen fertilization considerations for  newly planted and developing orchards. Total length is around 15 minutes. A quick overview of the presentation: Nitrogen is nitrogen. Several studies within CA have indicated that there is no benefit in using different types of nitrogen for fertilizing young almond trees. Some fertilizers, however, may influence soil pH as well as be more prone to leaching; Studies within Merced and Colusa COunty have indicated that newly planted trees will maximally grow with actual nitrogen applications between 3-4 ounces. This has to be adjusted for tree density and application efficiency; Developing trees have developing rootzones which leads to inefficient applications. If fertigating, the best irrigation system would deliver nitrogen directly to the rootzone of the tree (e.g. single line drip with punched emitters). If not possible, controlled release fertilizer has been shown to grow as well as conventional fertilizer and have a lower labor cost (one application and done for the season). The 120 day controlled release blend in this trial was supplied by Agrium Technologies; Do not apply more than one ounce of actual nitrogen per application per year of growth. This helps reduce lanky growth and nitrate uptake toxicity; Take into account residual soil nitrogen and nitrogen within the irrigation water if using a well. In some cases, these may provide sufficient nitrogen; Finally, don’t start too early. Give the trees time to grow and draw down some of the moisture within the rootzone. Around 6″ of growth should be visible prior to the first fertilization. Here is a link for a pdf copy of the presentation.

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Fertilizing one-year old trees – be careful!

Nitrogen is the most important element we can apply to our tree fruit crops. Almond growth and productivity depend on the availability and uptake of nitrogen. Most fertilizer recommendations are based on making nitrogen available to our trees so that a nitrogen shortage does not limit tree growth or productivity. Young almond trees don’t require as much nitrogen as older trees. I like Wilbur Reil’s rule of “one ounce of actual nitrogen per year of age of tree”. That rate can be applied several times per season, but never more than that at any one application. Thus, a first leaf (first year in your orchard) almond tree should not receive more than one ounce of actual nitrogen per any application. A five year old almond tree should not receive more than 5 ounces of actual nitrogen per one single application. The University of California only recommends one ounce of actual nitrogen per one year old tree over the course of the season, but I have been told by many growers and PCAs that this rate is not enough for the growth they desire. So, if you want to put out five ounces of actual nitrogen per one year old tree, do so in five applications and not all at once! I have seen many trees burned by nitrogen, especially if liquid fertilizers like UN-32 (urea ammonium nitrate 32 %) or CAN 17 (a clear solution of calcium nitrate and ammonium nitrate) are used in single applications. These liquid fertilizers are very effective and easy to use but it doesn’t take much to burn young trees. I do not suggest using these liquid fertilizers on first leaf trees–I prefer to see triple 15-15-15 (15% Nitrogen – 15% Phosphorous – 15 % Potassium) fertilizers used on first leaf trees. I like to

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