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Advanced Sensing & Management Technology in Specialty Crops

Pistachio Prediction Model

Update 2013 | Findings | Model

A New Tool in Nutrient Management

Muhammad Ismail Siddiqui and Patrick Brown

The Pistachio Prediction Model (PPM) uses nutrient analysis of spring leaf samples to predict late summer nutrient concentrations of nitogen (N) and potassium (K). Late summer sampling, which is currently the typical practice, provides the grower with little useful information on which to base fertilizer adjustments for the current season. Sampling and analysis early in the season offers management advantages on which the grower can base fertilizer adjustments for the current crop load.

PPM model development was based on data from three years (2009-2011) and across four geographical locations in California. The model uses the May sample data to predict the expected summer (July/August) nutrient (NK) values. The model adjusts for the foliar contamination of micronutrients and also calculates the Ca to Mg ratio.

The model is interactive; user input includes:1) Timing of the sampling. That is, Days After Full Bloom (DAFB) and, 2) Leaf nutrient concentrations for the following nutrients: N, K, P, Ca, Cu, Mg.

 

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Pistachio Prediction Model is an update released July 2014 in Excel format.

Leaf Sampling & Model Protocol

Spring Sampling

  • Collect leaves from non-fruiting, exposed branches
  • Collect 10 leaves per tree at 6-7 ft height, from around tree canopy
  • Sample at least 18 trees, at a distance of 25 yards from an orchard of average variability
  • Collected leaves may be pooled in one bag for analysis
  • Leaf samples should be collected between 30-45 days after full bloom

Analysis of plant nutrients required: N, P, K, Ca, Cu, Mg

To use the Model

Insert May nutrient concentrations (average) and days after full bloom (DAFB) in the May Values column

Summer Predictions of NK (%) will display in the Prediction column

For a pdf file providing protocol for use of the model: early-season leaf sampling and in-season N budgeting:
Pistachio Early-Season Sampling and In-Season Nitrogen Application Maximizes Productivity, Minimizes Loss

Contact regarding model: Muhammad Ismail Siddiqui

The model was validated in 2012 with data from 12 orchards in California, and  data from 10 orchards in Australia.