PRIMGHAR, Iowa — It seems that almost every discussion between agricultural producers starts with weather. The temperature, the wind direction, how hot it is, when it will rain – they all make a difference in how good the crop will be this year. A person tends to pay close attention to issues that affect their income!
In this column, I want to share some resources I use to follow the trends of weather’s impact during the growing season. First up are the soil moisture samples I take about November 1 each year. I go to specific sites in the nine counties I serve and pull soil samples to a depth of five feet. Corn and soybean roots grow to at least five feet deep in this region in most years. I pull those samples and calculate how much water the soil is holding that the corn or soybean crop can draw on during the next growing season. When at “field capacity” – the maximum amount the soil can store for the crop – we have about 11 inches of water that the crop can use. Corn and beans need about 22 inches during the growing season, so having a full amount available in the soil when the crop starts demanding it greatly reduces the risk of crop failure. Fall rain in 2017 has given us moisture levels at all sites I monitored in the region above the long-term averages, and all will likely be near field capacity by early June. That is a great start for 2018!
I am certain that almost everyone who has a smart phone has a weather app on it, or a weather website. My preferred weather site to monitor the local forecast is weather.gov. This is the website of the National Weather Service, but I believe most other commercial sites use the same data that comes from them in most cases. For weather junkies, do a web search for “Iowa Mesonet” and explore the data available for almost any digitally archived weather-recording network in the state of Iowa. However, you had better schedule some time for there is a huge amount of information available there. Click on the tabs at the top of the page and start exploring.
When monitoring weather conditions for agriculture in NW Iowa, I often go to the “Iowa Soil Moisture Network.” These weather stations collect wind and rain information, along with sunlight data for each day. Additionally, these stations have sensors in the soil to collect temperature and moisture information at 4”, 12” 24” and 50” depths. I often use the “plot time series” option to see how we are progressing during the growing season. Just select a site near you and then choose the time period you want to review.
Finally, search for “Iowa Mesonet Automated Data Plotter,” select the first option on the drop down list; followed by any selections you want on that next page, then click the make plot button and the charts will appear. I use this website to monitor growing and stress degree-days during the summer, comparing that and rainfall to normal – and to other years that seem similar.
There is lots to watch. Try some of these sites and explore!
— Joel DeJong, Field Agronomist, Iowa State University Extension and Outreach
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