Measuring soil nitrogen (N) prior to fertilizing can improve N fertilizer management. The soil nitrate quick test is a simple and low-cost test. It provides a ballpark estimate of the soil nitrate-N concentration in the rootzone. Nitrate is a highly plant-available form of nitrogen. Using the soil nitrate quick test when N fertilizer decisions are being made will help define a range of fertilizer rates appropriate for that field. This can provide several benefits. These include improved N use efficiency, lower input costs, improved grain yield or grain protein, and reduced N loss to the air or below the crop rootzone.
Over the past several years UCCE agronomists have been developing and refining information about the accuracy of the soil nitrate quick test compared to laboratory tests across different soil types and users. Based on more than 300 samples taken from 19 sites across California, we have developed a strong quantitative relationship between the value measured from an in-field soil nitrate quick test and an estimate of fertilizer equivalence.
We are excited to share several new extension resources based on this work. These resources are now available at a new UC Small Grains Agronomy and Research Information Center website:
Here users will find an interactive webtool, a video, and a printable document. Each of these provides step-by-step instructions for how to carry out the soil nitrate quick test. Links to the materials needed to conduct the test and information on how to interpret test values are also included. The webtools are notable because they provide automated conversion of quick-test values to fertilizer equivalence based on map-enabled, site-specific soil information.
Our goal for developing these resources was to simplify and improve the process of measuring and interpreting soil nitrate values so that soil nitrate testing would become a more widely used tool when fertilizing California small grains. Please take a few minutes to interact with these resources and consider incorporating them into your agronomic toolkit. If you have any questions about the resources or using the soil nitrate quick test, reach out to the authors of this blog post or any of the individuals listed at http://smallgrains.ucanr.edu/Contact_Us/.Also, stay tuned to this blog space for upcoming posts on other topics related to optimizing N fertilizer management in California small grain crops. This information is being produced by a statewide group of UCCE agronomists with the support of the CDFA-FREP and NRCS-CIG programs. Project contacts are: Taylor Nelsen, Nick Clark, Michelle Leinfelder-Miles, Konrad Mathesius, Sarah Light, Thomas Getts, Giuliano Galdi, and Mark Lundy.