The SSJV MPEP Committee is developing and compiling online tools and resources for growers and advisers. The following links provide information related to nitrogen management planning.
This calculator can be used to estimate N removed (R) and the ratio of N applied (A) to N removed (A/R). Results can be calculated from inputs for a single crop or for multiple crops. The conversion factors were developed by Dr. Daniel Geisseler based on best available information, and will be refined as additional research results become available. Calculations may be completed online or offline.
California Fertilization Guidelines (California Department of Food and Agriculture)
These fertilizer guidelines were written by scientists from the University of California, Davis, with support from CDFA FREP. Fertilizer guidelines are available for 28 crops.
Nitrogen (nitrate and ammonium N) in irrigation water is as readily available to crops as N in chemical fertilizers. So, when growers account for N in irrigation water, they can reduce rates of fertilizer N application. This calculator converts nitrate and ammonium found in irrigation water, as measured by a laboratory or other method, into pounds of N applied per acre. A fact sheet is available here.
This link includes a directory of publicly available tools and resources related to nitrogen management planning.
Created by Created by Irfan Ainuddin, Patricia Lazicki and Daniel Geisseler, of the Department of Land, Air and Water Resources at the University of California, Davis. The values calculated on this website are estimates based on literature data for N uptake. They are not recommendations. Weather conditions, management and variety selection all can affect N uptake and availability. It is therefore important to monitor the N status of the field during the season with soil or leaf analyses and to make adjustments to the fertlizer program. The calculator does currently not work on Internet Explorer. Please use Firefox or Chrome.