Peanut growers can benefit from the following article on irrigation for peanuts by David Hall, Cale Cloud, and Wesley Porter (UGA Extension Irrigation Team).
Unlike 2019 which was very hot and dry during May and June, 2020 has been cooler and wetter. We’ve received almost adequate, if not adequate rainfall to get the crop through the early season in most of the state. On top of the rainfall, unlike the high abnormally dry and hot weather with very high evapotranspiration (ET) rates during 2019, we’ve had much lower ET. Getting an acceptable stand has been challenging in many cases due to cool, wet and crusting soils. Planting dates have been strung out and in many areas and early June peanut plantings will occur. Keep this in mind when you are looking at the water use for your crop, as a single farm may have peanut maturities spread across a month’s time frame.
Keep track of the graph below or use our UGA Extension quick irrigation reference guide (https://extension.uga.edu/publications/detail.html?number=C1189) in the field throughout the month of June, stay on top of your irrigation requirements. Contact your local Extension office if you need a copy of the irrigation reference guide. If you planted your peanuts during late April or early May, most of these earlier planted peanuts will be beginning to bloom, so expect water usage to gradually increase. Peanuts will begin flowering on average around 40 days after planting.
Remember the water requirement is IRRIGATION and RAINFALL! Also consider irrigation efficiency especially on hot dry days. A typical pivot is 85% efficient, so don’t under-irrigate, but at the same time don’t over-irrigate either as research has shown reductions in yield just as significant for over-irrigating as for under-irrigating. Good record keeping and a sound irrigation scheduling strategy can aid significantly in increasing profitability in multiple ways, including reductions in irrigation applications, correlating to reductions in energy requirements, and potentially increases in yield.
A couple of quick reminders regarding irrigation of peanuts. Early irrigation applications can tell you very valuable information regarding your water application uniformity. If a Mobile Irrigation test was not
conducted, pay close attention to the way your soils dry out after an irrigation application. If your peanuts were planted into conventional tillage, this will be easy to see especially prior to full canopy closure. Visible bands drying out quickly or bands staying wet for longer periods are signs of poor uniformity. Go to these areas of your pivot and address them now. As the peanut canopy develops and laps, the obvious signs will not be visible. The hot dry weather last year made it easy to see if your pivot
was working properly due to the extreme heat and drought. The under applying nozzles were easy to see by the evidence presented as stressed crops in bands under the pivot. Doing the same thing twice expecting different results is never good.
Lastly, if you are using soil moisture sensors and have “weighted” the sensors, now is the time to balance the sensors because of increased root development and crop progression. Consider using other tools in conjunction with your moisture sensors. Irrigator Pro (https://irrigatorpro.org/) integrated with a soil moisture sensor system through UGA trials has repeatedly shown higher yields than the Checkbook method. For more assistance and information on Irrigator Pro usage, contact your local UGA Extension ANR Agent, The Irrigator Pro website includes a step-by-step video tutorial on how to download the app.