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K-State Agronomy eUpdates

Department of Agronomy

Kansas State University

1712 Claflin Rd.

2004 Throckmorton PSC

Manhatan, KS 66506

785-532-6101

agronomy@ksu.edu

Extension Agronomy

Wheat planting conditions as of mid-September 2016

Recent weather pattern

There have been significant rains throughout most of Kansas over last 30 days (August 16 - September 15), especially in central and eastern portions of the state (Figure 1). Most of the state received more than 4 inches of precipitation, and some regions received more than 10 inches in the period. Most of the state was at least 1.7 inches above normal for this period, with exception of southwest Kansas (Figure 2). While these rains can possibly translate into a “full moisture profile” going into the wheat growing season for most of the state, it can also provide some challenges for crop sowing and field operations.

Figure 1. Total cumulative precipitation (top chart) and departure from normal 30-day precipitation totals (bottom chart) for the period between August 16 and September 15, 2016. Map by K-State Weather Data Library.

 

Heavy rains continued during the period of Sept.6-12, with the emphasis on south central Kansas for the week ending on the 12th of September (Figure 2). Additional rains fell in the northeastern portion of the state on Sept. 14 and are not included in Figure 2. The heaviest rainfall reported was 13.4 inches in Clearwater, Sedgwick County. By contrast, the western divisions were all below normal for the period, averaging less than a quarter of an inch or about a third of normal for the period. The statewide average was 1.91 inches or 252 percent of normal.

Figure 2. Total cumulative precipitation in the period between September 6 and September 12, 2016. Map by K-State Weather Data Library.

 

With the heavy rains over the last 10-14 days, flooding concerns occurred in the eastern and central parts of the state, while lack of recent rainfall increased concern for sufficient topsoil moisture in southwest Kansas, as winter wheat planting begins.

Future forecast

The weekly precipitation forecast for Kansas indicates that the probability of 0.1 to 1.75 inches of precipitation for the next 7 days. Central and north central Kansas have the highest precipitation probabilities (Figure 3). This forecast indicates that the heavy rainfall pattern observed in recent weeks may occur again in the next seven days for most of the state, which could present challenges for producers wanting to sow wheat at this time.

Figure 3. Weekly precipitation forecast as of September 16, 2016. Precipitation probabilities in Kansas for the next 7 days range from 0.1 to 1.75 inches.

 

Possible challenges for wheat planting and crop establishment

The current wheat planted acreage in Kansas, according to the latest USDA-NASS Crop Progress Report, was 4% as of Sept. 12. This is slightly below the 1994 - 2016 average of 6.2% (Figure 4), but is not a delay to be concerned about.

Figure 4. Percent wheat area in Kansas planted by September 13. Data shown for the period 1994 – 2015 as reported by the USDA-NASS Crop Progress Reports (https://www.nass.usda.gov/Publications/National_Crop_Progress/).

 

There could be a further delay in planting progress compared to previous years, mostly due to excessively moist soil conditions.

Planting wheat under wet conditions can present either mechanical or biological challenges.

  • Mechanical challenges usually involve not being able to get equipment in the field to perform plowing or sowing operations, mudding up the equipment after field operations are started, and increased soil compaction due to machinery traffic in moist soils. Soil compaction can restrict adequate root growth, affecting plant anchorage and decreasing its ability to uptake water and nutrients.
  • Among possible biological challenges, planting wheat into wet and cold soils can delay the crop’s emergence, possibly increasing early-season disease and insect problems. In these situations, a fungicide and insecticide seed treatment might be a good option, especially if planting gets delayed.

 

In mid-September, we are still at the beginning of the optimum planting date for wheat for most of the state, so producers should not hurry and sow wheat into extremely moist soils. Waiting for the water to drain and/or evaporate so the soil dries adequately before performing the sowing operation would be the best option.

Planting wheat into a dry topsoil, as is the condition of many parts of southwest Kansas, can also be challenging. While a good seed distribution is generally achieved when sowing wheat into dry soils, the lack of moisture for germination can result in uneven stands and high within-field stand variability (Figure 5), which can ultimately impact resource-use efficiency and grain yield. Producers in southwest Kansas who are facing dry topsoil conditions have three main options:

  1. Sowing the wheat at normal seeding rate and depth, and hope for rain
  2. Plant deeper than usual to reach moisture
  3. Wait for rain before planting

 

As it is still mid-September and we are in the early portion of the optimum sowing date range, producers should consider options 1 or 3 before option 2 above. Warm soils, typical in mid-September, can reduce wheat coleoptile length, which can result in sub-optimal stands if wheat is sown deeper than usual. For more information on the advantages and disadvantages of each of the options above, please click here.

Figure 5. Uneven wheat stands from sowing into dry soils. Photo by Romulo Lollato, K-State Research and Extension.

 

Romulo Lollato, Wheat and Forages Specialist
lollato@ksu.edu

Mary Knapp, Weather Data Library
mknapp@ksu.edu