Excerpt from the article “Pistachio Nitrogen Nutrition: What do we know and how do we manage?” by Douglas Amaral, Orchard Advisor, Kings and Tulare Counties, UC ANR, and Patrick Brown, Professor, UC Davis on the San Joaquin Valley Trees and Vines website.

More than ever before, California pistachio growers have a wide selection of nitrogen (N) management tools at their fingertips today. Given that N fertilizer mismanagement have increased significantly and the Irrigated Lands Regulatory Program (ILRP) have implemented new regulations to prevent agricultural runoff from impairing surface waters, it only makes sense to use available tools to improve Nitrogen Use Efficiency (NUE).

In order to achieve maximum productivity and to reduce N losses to the environment, a close attention to the four R’s – Right Rate, Right Time, Right Place, and Right (re)Sources – is needed in all orchard fertility programs. Remember, you need to TRAP the N in the soil: TIME nitrogen application according to tree uptake patterns, identify/understand available nitrogen RESOURCES (fertilizers, composts, manure, cover crops, irrigation water), apply the AMOUNT needed according to tree demand, and PLACE N to the tree’s active root zone. Following the 4 R’s principle can be viewed as a balancing act with the goal of applying adequate N to supply tree demand for growth and fruit production.

For more information about what tools are available and how to use them to maximize NUE, see the full article on San Joaquin Valley trees and Vines.