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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8 thoughts on “Young Tree Nitrogen Fertilization

  1. Great presentation David – really good.

    I have a question about the nitrogen burn you are referring to in slide 15 (Presentation time 10:42 ). You call it a shepherd …… – i didn’t really understand the exact wording. What does that mean and what are the long-term effects ? Is the growth stunted or discolored?

    Thanks and well done again

    1. Shepherd’s crook was the term I used to describe branches that curl over on the top. Rapid uptake of nitrate – which often occurs on hot days after a fertilization– causes the tender tissues to die and wilt. Trees recover – usually relatively rapidly – and push new growth from behind the damaged wood.

      In my experience, it slows the growth of the trees, causes a bit of a scare, but usually by the end of the season, not much difference between affected and un-affected trees can be observed.

      Hope that aids in the clarification. I am glad that you enjoyed the presentation.

  2. Stupid question here. Can you do a post explaining exactly what “first leaf” and other growth stages actually mean? I can’t find any information on this online. It’s such a commonly used metric, a detailed explanation and diagrams would be very useful. Can you refer me to anything? Thank you.

    1. Daniel,
      Yes, it is a bit of a colloquial term. “First leaf” means the first time a tree has leafed out in the orchard. This is easy with bare roots – it is the year after planting. Gets a little more confusing with potted plants – if a dormant or spring planting, probably year planted. If a fall planted pot, the information provided above is probably relevant for the year after planting (i.e. planted in fall of 2015, first leaf would be 2016).

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