To address nitrate pollution of groundwater, the Central Valley Regional Water Quality Control Board has initiated a regulatory program requiring growers to utilize nitrogen management practices that mitigate nitrate loading. Because nitrogen plays such a critical role in in the growth and development of avocado trees — and because it can be difficult to ensure trees are receiving the optimal amount of nitrogen — the University of California Department of Agriculture and Natural Resources has created the Nitrogen Management in Citrus and Avocado publication.
This document is designed to optimize growers’ application of nitrogen while reducing nitrogen leaching by focusing on applying nitrogen at the right rate, at the right time with the right placement and from the right source (otherwise known as the four R’s of nutrient management). The guide provides specific examples for the rate of application based on the age, alternate bearing status and vegetative state of the tree and discusses the optimal spring/fall application periods. In addition, the document provides guidance on how to conduct leaf analysis and what optimal concentration percentages to look for.