Soil Health
Fertilizer Guidelines for Vegetable Crops in Arizona
Special Sections (4)
Plant Tissue N Monitoring (4.2)
In 1990 Doerge, Roth, and Gardner published a document outlining protocols and criteria for using a nitrogen (N) tissue testing method as an aid in N management (7). This document was prepared to assist growers to stay in compliance with the requirements of state mandated best management practices (BMPs) for N fertilizers (Section 4.8). However, studies conducted by the current author in the Lower Colorado River Region, where vegetable crops are primarily irrigated with furrows and most in-season N requirement is applied through the sidedress method, showed that soil nitrate-N testing is a more reliable prognostic tool (Section 2.1). Furthermore, in a cropping system that uses the sidedress method, the first N application sometimes occurs at early crop growth stages, before the plant part to be sampled for tissue analysis is fully differentiated from the rest, and therefore plant tissue test cannot be made. However, plant tissue tests are useful diagnostic tools for all systems and have been reported to have prognostic applications in buried drip fertigation systems (77). Thus, links to publications by Doerge et al. (7) on plant tissue testing methods related to each vegetable crop of interest are provided next.
Cauliflower:
https://acis.cals.arizona.edu/all-publications/publications-view/nitrogen-management-guide-for-cauliflower