Pistachio Prediction Model
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.
Leaf Sampling & Model Protocol
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:
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.