Row crop planting progress and conditions in Kansas

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For all row crops, planting progress in Kansas is further along this year than it was at the same time last year. Corn is the furthest along, but air and soil temperatures during this last week (May 12-16) did not help progress the crop. Because of the slow progress of the crop, differences in planting date of about one week or even more will be hard to notice at the end of the season. For both soybean and sorghum, planting progress is ahead of last year, and the coming weeks will be critical in shaping the potential yield.

Corn status in Kansas

The most recent Kansas Agricultural Statistics (KAS) crop progress report estimated that almost three-fourths of the Kansas’ corn crop had now been planted as of earlier this week, ahead of the average (63%) and well above last year’s corn planting progress (29% for 2013 season). KAS also reported that 35% of the corn is already above the ground, compared to the 5-yr average (30%). Last year at this time, only 5% of the corn had emerged.

One of the most critical factors for corn during emergence is the uniformity of the seedlings. Uneven corn stands causes yield losses. For example, when 25-50% of a corn stand emerges between one to three weeks late, yield losses can be close to 7-10%, according to published research by Emerson Nafziger and colleagues at the University of Illinois. Yield losses increased as the difference in emergence in the corn stands are exacerbated.

The main factors controlling the uniformity in corn are soil moisture, soil temperature, seeding depth, and good seed-soil contact. In addition, planting dates can affect uniformity of emergence in corn. In a demonstration experiment planted this year, early (March 21) vs. “normal” (April 16) planting dates resulted in differences in plant emergence uniformity. This was related to the soil temperature at each planting time. For the early planting date, soil temperature measured at 4 inches was 46°F; while for the normal planting date was 52°F (Figure 1).

Figure 1. Corn planting dates affected stand uniformity in this test. Photo by Ignacio Ciampitti, K-State Research and Extension.

Soybean status in Kansas

The overall planting progress of soybean in the most recent Kansas Agricultural Statistics report was 16%, well ahead from the last year’s 1%, but within the average of the last 5-year planting conditions and progress (15% average). The overall emergence for soybean takes place between 5 to 20 days after planting, depending on soil moisture, soil temperature, and seeding depth among other critical factors.

After planting, acceptable soil temperatures for proper soybean emergence and establishment are around 50 °F. Although soybean can emerge at lower temperatures, stand uniformity and final number of plants can be compromised. A research study at Purdue University showed that the number of days from planting until emergence will be reduced as the planting date gets later, related to higher soil temperatures, which is not surprising. Still, final plant stand (success of emergence) was highest when all plants emerged within two weeks after planting and soybeans were planted when soil temperatures were not too cool. A planting date experiment is currently underway in Kansas for diverse locations from central to eastern areas. For Manhattan, the first planting date was April 22nd with soil temperatures around 59 °F (Figure 2). Plants emerged after 20 days and stand uniformity was not especially good, related to the lower temperatures that occurred last week.

Figure 2. Early planting of soybean and stand uniformity. Photo by Ignacio Ciampitti, K-State Research and Extension.

Sorghum status in Kansas

Kansas Agricultural Statistics projected that 3% of sorghum crop in Kansas was planted as of May 11, ahead of last year’s pace (1%), but slightly below the 5-yr average (4%).

Optimum soil temperatures for sorghum are around 50-55 °F. If the crop is planted when the soil temperature is below 50 °F and in wet soils, failure in emergence can be expected (Figure 3). In a demonstration plot, sorghum was planted in late March (March 21) and just few plants were coming out 4 to 5 weeks after planting. In contrast, when plots were planted during the first week of May, when soil temperature were above 60 °F (measured at 4”), both corn and sorghum emerged about one-week after planting (Figure 4).

Figure 3. Sorghum vs. corn emergence when planted early on March 21. Photo by Ignacio Ciampitti, K-State Research and Extension.

Figure 4. Sorghum vs. corn emergence when planted at a “normal” planting time, May 6. Stand uniformity was similar in the two crops. Photo by Ignacio Ciampitti, K-State Research and Extension.

Thus, soil temperature is a much more critical factor for sorghum then corn. In a planting date experiment, sorghum planted during the first week of May showed excellent uniformity of emergence and final plant stand (Figure 4). Plants emerged a week after planting.

Figure 5. Sorghum stand uniformity when planted about the first week of May, with a soil temperature at 4” of about 65 °F. Photo by Ignacio Ciampitti, K-State Research and Extension.


As the growing season progresses, the low temperatures during this week will minimize the difference in emergence and seedling development that might normally be seen with different planting dates. Emergence and early growth has been unusually slow this spring so far due to a lack of growing degree units (GDUs). For example for Silver Lake, the GDUs accumulated from May 9-15 were 90; while for the same period in the last year, the GDUs were close to 110 (almost 20 units more in just one week). In general, for corn, 125 soil GDUs are required from planting to emergence.

One important factor to be considered is residue cover. Even though we noticed better soil moisture under more residue, the emergence process can take longer (under the current temperatures) with heavy vs. low residue. Those differences will show up within the same field as uneven crop stands.

Lastly, the low temperatures overnight on May 15-16 (mid-30s), will delay the progress of the crop, with a potentially much larger impact on the crop that was recently planted.

For more information about early season crop topics, check the following resources:

Diagnosing corn early-season growth problems (eUpdate #454, May 2nd):

Soybean seeding rates and optimum plant populations (eUpdate #453, April 25th):

Freeze effects injury on corn (eUpdate #452, April 18th):


Ignacio A. Ciampitti, Crop Production and Cropping Systems Specialist