Looking at Soil Temperatures
As October transitions to November, Fall NH3 application will be ramping up soon. How soon depends on three key things which includes growers completing harvest, ground moisture suitable for application and ground temperature. The first two of these are more on the ‘operational’ side as getting the crop out is the key priority and ground that is too wet will cause many problems both in actual NH3 application and the subsequent season (poor seal; N-loss, knife tracks). Excessively dry soil conditions I don’t expect this area to see this fall as presently there is ample soil moisture. Soil temperature is what we closely monitor. See the image from the Innovation Farm weather station. This is a Data on Touch screenshot looking specifically at the 5 inch (orange line) and 10 inch (red line) soil temperature probe data from October 10 through today at 8:30am. The air temperature is the (yellow) line. I pulled data from four other weather stations including Crescent City and they were very closely matched. You can also see this on your phone or IPad ‘WeatherView’ App or the Davis ‘WeatherLink’ App. As can be expected for this time of year, we are seeing a downward trend with soil temperature. At a steady 50 degrees or less at the 4-5” depth, the conversion from the stable ammounium-NH4 to leachable NO3 (nitrate) is greatly reduced (nitrogen stabilizer is assumed). That is the soil temperature target and is one of our considerations to pulling the trigger on NH3 application. Take advantage of these informative phone Apps and pay close attention to the extended weather forecast!