University of California Agriculture and Natural Resources announced on Apr. 16 the use of nitrate-sensitive test strips as a practical tool for measuring plant-available nitrogen in both soil and irrigation water. This method aims to help growers manage fertilizer use more efficiently, especially as nitrogen fertilizer prices have risen significantly since last year.
Efficient management of nitrogen not only helps reduce production costs but also supports environmental protection by minimizing nitrate runoff into ground and surface waters. The organization said that using these quick tests allows growers to determine the amount of available nitrogen without waiting for laboratory results, enabling timely decisions about fertilizer application.
The process involves collecting representative soil samples from various field locations, extracting nitrates with a calcium chloride solution, then using test strips to measure concentrations based on color changes. Adjustments are made according to soil texture and moisture content using provided tables. For irrigation water, the strips can quickly indicate nitrate levels after dipping them into a sample, allowing calculation of how much nitrogen is being added through watering.
To ensure accurate results, the announcement recommends best practices such as using sturdy sampling tools, collecting composite samples from multiple spots in a field, keeping both test strips and samples cool before analysis, thoroughly mixing cores from similar depths, adding correct volumes during extraction, timing color development precisely when reading strips, and periodically checking strip accuracy against standard solutions.
Online resources like CropManage can help integrate factors such as crop growth stage or irrigation scheduling with measured data to recommend optimal fertilizer rates. The Soil Nitrate Quick Test Web Tool is also available for step-by-step guidance tailored to different soils.
University of California Agriculture and Natural Resources secures funding through public contributions to support its programs according to the official website. The organization promotes sustainable practices aimed at strengthening resilient ecosystems and economic vitality according to the official website. It utilizes nine research and extension centers representing California’s diverse ecosystems according to the official website, manages Cooperative Extension services within the University of California system according to the official website, conducts over 33,810 educational events annually with participation from more than 18,420 volunteers according to the official website, and has gained recognition for linking research directly with community needs according to the official website.
Growers seeking advice or guidance on interpreting quick test results are encouraged by UC Agriculture and Natural Resources staff: “Myself and my staff are happy to help!”