Development of Leaf Sampling and Interpretation Methods and Nutrient Budget Approach to Nutrient Management in Almond (Prunus dulcis (Mill.) DAWebb)

In the following we report the results of a series of large integrated field studies conducted in almond from 2008-2012. One of these projects principal goals was the systematic reexamination of both current leaf-sampling protocols and the application and interpretation of established critical values. A second principal goal of this project was to quantify whole orchard nutrient budget analysis and nutrient demand. A reanalysis of the use of leaf sampling and critical values in almond suggests that leaf samples can be collected approx. 40 days after full bloom (DAFB) and that algorithms can be used to interpret nutrient concentrations with respect to a previously established critical value even if that standard was established at a different sampling date. Measurements of multi-site yield and nutrient analysis has been used to establish crop demand curves and patterns of nutrient uptake throughout the season. In almond more than 80% of the total N is accumulated in fruit by mid-June more than two month prior to harvest. Yield and N concentration determine N demand which varies with fertilizer application rate. A 1000 kg kernel yield exports 59 kg N for 309 kgN/ha application.