How Dry was the 2021 Growing Season at the Arlington UW-ARS?

 

This year, southern Wisconsin experienced dry conditions during the growing season. In spite of low precipitation, corn grain yields have been good to excellent for most farmers in the area.

The University of Wisconsin Agriculture Research Station (UW-ARS) at Arlington began collecting weather data in July of 1962. How did the 2021 growing season compare to the previous growing seasons at Arlington for precipitation? 

Growing season (April 1 to October 31) weather data (1963 to 2021) were obtained from the Midwest Region Climatological Center for the UW-ARS at Arlington. A 58-year average was calculated along with the standard deviation of the mean. The standard deviation was multiplied by 1.25 to get the wettest and driest growing seasons over this time period. The accumulated precipitation was compared to the average for each day during the study period. The daily deviations from the average accumulated precipitation are shown in Figure 1.

The wettest growing seasons during this time period were 2019, 2018, 2010, 2008, 2006, 1993, and 1980. The driest growing seasons were 2012, 1988, 1976, 1971 and 1963 (click on each year to see a more detailed weather summary). The 2021 growing season ranks as one of the driest on record for the UW-ARS at Arlington. Precipitation patterns can be localized varying dramatically even within a farm.

In spite of being one of the driest seasons on record, grain yield of the UW Corn Hybrid Performance Trial averaged 254 bu/A (see preliminary results here).

Figure 1. Seasonal precipitation deviations from April 1 to October 31. Years were selected using +1.25 standard deviation of the 58-year average.

 

Record grain yield years usually have the following characteristics:

1. Earlier than normal planting with adequate spring soil moisture to activate herbicides,
2. A mild moisture stress ("mini-drought") during early corn development that fosters deep root penetration into the soil profile with soil moisture eventually replenished to normal levels by pollination (1-inch of precipitation per week),
3. Corn development typically ahead of normal at some point during the growing season, 
4. A fall killing frost at the end of September or during October, and 
5. Dry fall harvest conditions.

The 2021 growing season  was typical of a record year, except that corn was challenged with a late-May frost event, rainfall of less than 1-inch per week during July to September, and a late incidence of Tar Spot. The lesson I learned from this season is that corn could get by with less than 1-inch of rain per week during July to September and still yield well. The efficient use of water might be attributed to the European Corn Borer transgenic trait grown in most modern hybrids.

Preliminary Grain Yields for the UW Corn Hybrid Evaluation Trials

Grain corn is rapidly being harvested across Wisconsin. Many farmers are reporting good yields at relatively dry grain moisture.

Preliminary grain yields of hybrids in the UW Corn Performance Trials averaged 224 bu/A at 22.3% moisture (Table 1). The highest yielding location was Fond du Lac at 260 bu/A. Good yields were reported at most sites in northeastern Wisconsin. Test weight ranged from 53 to 57 lb/bu. Little lodging was observed, although plant stalk quality is an issue. Hopefully high winds will continue to stay away through the rest of harvest. Tar spot was a significant disease at locations in the southern zone.

Table 1. Preliminary Grain Yields for the 2021 UW Corn Hybrid Evaluation Trials.

Final results will be available in November. Watch for the 2021 results at http://corn.agronomy.wisc.edu/HT/Default.aspx.

Preliminary Silage Yields for the UW Corn Hybrid Evaluation Trials

Corn harvest is well underway with 32% of Wisconsin corn acreage harvested for grain as of October 17 (USDA-NASS). Corn is mostly mature (96%) with 68% good to excellent.

Preliminary corn silage yield for hybrids in the UW Corn Hybrid Evaluation program averaged across all locations was 10.6 T DM/A at 62.9% forage moisture (Table 1). Good yields were observed in spite of drought conditions at many locations. The highest yielding location was Arlington at 12.0 T DM/A averaged across 195 plots. 

Corn silage drydown was faster than normal. Two weeks prior to harvest, we inspected all trials and determined a typical start-date for harvest. However,  forage moisture proved drier than normal at many sites, although the overall average of 62.9% which was close to our target moisture of 65%.

  Table 1. Preliminary Silage Yields for the 2021 UW Corn Hybrid Evaluation Trials.

 

We are currently grinding and running forage quality analysis on all samples collected. Final results will be available in November.