Spring weather is a critical time for many farming operations; your tillage and cover crop plans can influence your success. Although the weather forecast for your region can be helpful, the impact on your operation depends on factors like field management, soil conditions, farming system, timing, and equipment. The extended outlook may help identify an overall pattern for the region, but it should not replace proper planning and field-by-field adjustments.

Current Conditions and Outlook

We are coming out of a La Niña winter, which did not follow the typical La Niña pattern for many areas. What it did do was provide some precipitation relief for portions of the West, Central/Northern Plains, and Lower Delta. This will help with some soil moisture recharge, but many areas, such as portions of the Southern Plains, missed some of those events. The overall temperature pattern was colder than normal in the western half of the U.S. and warmer than normal to the east.

The West received much-needed precipitation and snow. This snowpack (Figure 1) helps recharge reservoirs and rivers. In addition to the immediate impact, mountain snow provides another source of moisture for the weather systems that move across the Rockies and into the Plains. It is also valuable for farmland dependent on snow melt for irrigation during the growing season.

Figure 1 - Map of the Western U.S. percentage of normal snow water equivalent as of March 15, 2023. Map from USDA/NRCS National Water and Climate Center. https://www.nrcs.usda.gov/wps/portal/wcc/home/snowClimateMonitoring/snowpack/snowpackMaps

La Niña conditions are expected to dissipate quickly and turn neutral by spring/summer (Figure 2); however, the ENSO (El Niño Southern Oscillation) cycle does not typically have strong influence on our springtime weather and is less useful for the extended forecast.

Figure 2 - Official ENSO probability forecast from the NOAA Climate Prediction Center. https://www.cpc.ncep.noaa.gov/

The Climate Prediction Center has released extended outlooks for the three-month spring period (April-May-June) and the overall pattern shows higher chances for wetter than normal in the Central/Eastern Corn Belt and drier than normal for the Southwest (Figure 3).

Figure 3 - Seasonal temperature and precipitation outlooks from the Climate Prediction Center. Outlooks show the percent chance of receiving above or below normal conditions. https://www.cpc.ncep.noaa.gov/products/predictions/long_range/

Temperatures may hold onto the cooler pattern in the northern region and warmer in the south and east. The outlook for the near term still has high odds for above-normal precipitation persisting in the western U.S., so this could indicate a quick shift the latter part of the spring period to drier conditions in that region.

Soil moisture coming out of winter is important for agronomic decisions, and there was improvement in some areas. Looking at the whole rootzone, there is still a lingering drought in the Western Plains and portions of the East Coast/Mid-Atlantic (Figure 4). The surface soil moisture is higher for many areas; however, this is extremely variable and can quickly change with a couple rain events. The forecast for increased chances of above-normal spring precipitation (it’s already the wettest season) in the Corn Belt increases the odds for wet fields at planting. Excessive surface moisture will have a significant influence on planting success, root growth, and overall field accessibility.

Figure 4 - The satellite-based root zone soil moisture map from March 13, 2023. Map from NASA - GRACE https://nasagrace.unl.edu/data/20230313/GRACE_RTZSM_20230313.png

The current soil temperatures across the primary growing areas are close to normal. The actual soil temperatures at planting will be influenced by air temperature, sunlight, soil moisture, and surface residue, among other variables. As we progress forward, those areas with higher odds for warmer-than-normal temperatures and areas with less soil moisture will warm faster than areas with wet soil and cooler temperatures.

Key Considerations This Spring

Excessive Soil Moisture:

Fields with heavy residue are likely to be wetter than tilled fields; however, conducting tillage now with wet soil can cause more compaction, crusting, and/or clods. Similarly, planting in wet soil can cause sidewall compaction, limit root growth, and cause unevenness. Strip tilling wet soil can cause the same issues as full tillage. Issues from conducting field work on wet fields will linger all season and should be avoided, if possible.

Cold Soil Temperatures:

Cold soil can delay germination and increase vulnerability to diseases, insects, and animal predators. The general rule for corn is to plant when soil temperatures hit 50°F at your planting depth. Soybeans can germinate in as low as 50°F soil temperatures, but warmer temperatures provide a more uniform emergence. Manual soil temperatures can be measured with a thermometer, but make sure to make the measurement at the same depth and time each day to get a running average. Your state may also have a weather network providing daily soil temperatures.

Air Temperature Pattern:

If you are terminating a cover crop with herbicides, the air temperature will influence your success. Cool temperatures can reduce the effectiveness of the termination, so be sure to check the herbicide product label for temperature guidelines. Learn more about terminating cover crops in this article by Iowa State University.

Also, consider the frost and freeze risk when planting your cash crops, especially if you are seeing an early season warmup. Early season crop growth followed by a strong cold snap could create freeze injury on crops that may be growing “ahead of schedule.” See Figure 5 for the median last date for a hard (28°F) spring freeze.

Figure 5 - Map showing the median last date for a hard freeze (28°F) for the U.S. Map from the Midwest Regional Climate Center. https://mrcc.purdue.edu/VIP/frz_maps/freeze_maps.html#frzMaps

List of Resources:

• Climate Prediction Center: https://www.cpc.ncep.noaa.gov/
• High Plains Regional Climate Center: https://hprcc.unl.edu/maps.php?map=ACISClimateMaps
• NRCS Snow Monitoring https://www.nrcs.usda.gov/wps/portal/wcc/home/snowClimateMonitoring/snowpack/snowpackMaps
• Jasa, P. (2019) Wait For Better Conditions Before Heading Out on Wet Soils. UNL CropWatch. https://cropwatch.unl.edu/2019/wait-better-conditions-heading-out-wet-soils
• Bauder, S. (2021) How Early is Too Early to Plant Soybeans. South Dakota State Extension. https://extension.sdstate.edu/how-early-too-early-plant-row-crops
• Ciampitti, I., Ducnan, S., Shoup, D., Ruiz Diaz, D., Presley, D. (2015) Considerations for corn planted under wet conditions. Agronomy eUpdates. Kansas State University. https://eupdate.agronomy.ksu.edu/article_new/considerations-for-corn-planted-under-wet-conditions-509-3
• Nielsen, R.L. (2019) Soil Compaction: The “Gift” That Keeps on Giving. Corny News Network. Purdue University. https://www.agry.purdue.edu/ext/corn/news/articles_19/SoilCompaction.html
• Nielsen, R.L. (2021) Soil Temperature and Corn Emergence. Corny News Network. Purdue University. https://www.agry.purdue.edu/ext/corn/news/articles_21/SoilTempEmergence-0412.html