The 2010 ASHS Annual Conference

Currently, the application of fertilizer and water in orchard crops follows largely standardized practices with limited consideration of temporal, climatic and crop variability. This approach constrains our ability to improve management, results in loss of potential income and causes negative environmental impact. In this project we strive to address this issue by integrating 1) new approaches to determine crop demand with spatial and temporal accuracy, with 2) advanced methods of estimating current crop status and performance with 3) the development a new site specific orchard management platform. In this poster (#2 of 2), we discuss integrated approaches to define real time crop ‘status' for water and nutrients with high spatial and temporal specificity in deciduous perennial crops. In a partner poster we present advanced methods for crop ‘demand' determination. A series of 8 research sites were established in 2008 throughout California, New Mexico and Texas in Almond, Pistachio and Pecan. Multiple in-season determinations of crop water and nutrient (all essential elements) have been conducted across all sites using a variety of methods and at several spatial scales from individual tree analysis (>1,500 individual data points at each sampling), to within canopy, above canopy and remote (aerial and Satellite) imagery. Analyses that have been conducted include: tissue nutrients (tissue sampling and elemental analysis; leaf-canopy-remote spectral analysis); plant water (plant stem water; modeled plant water status/demand (Eddy CoVar modeling, Sebal modeling, Warf Modeling); soil water (neutron probe, soil conductivity and capacitance, direct sampling). Preliminary results will be presented on the following: Nutrient and water variability within and between orchards and time Comparative efficacy of nutrient analyses by multiple methodologies (leaf analysis, SPAD, Ping Meter, NIR, hyperspectral analysis) Comparative efficacy and cross validation of water determination in plant and soils by multiple methodologies (stem water potential, spectral analysis, modeled demand) Impact of fertilizer rate trials and irrigation methodologies on crop response