Winter Wheat Varieties For Waterlogged Soils

Steve Lyons and Steve Jones

Washington State University, Mount Vernon Research and Extension Center

 

The “excess” wet weather we usually experience in the late fall in northwestern Washington causes many fields to flood or become waterlogged. Waterlogging occurs when the soil profile becomes fully saturated to the point that standing water may appear on the soil surface. Rarely will an entire field be waterlogged; usually it is only seen as ponded areas in the lower lying areas of a field where water can no longer move through the soil profile.

 

Basically, waterlogging is when water replaces the air in the soil pore spaces. Among other problems, waterlogging causes 1) lack of oxygen in the soil, 2) restriction of aerobic respiration by the growing roots, 3) changes in soil chemical properties and the availability of soil elements and 4) decrease in nutrient uptake. Under warm soil conditions when plants are actively growing, damage may occur after being underwater for just a few days. But when they are dormant and soils are frozen or very cold as they are in the late fall or winter of northwestern WA, the plants survive for much longer because the amount of oxygen required for root respiration is greatly reduced.  Literature contains many references showing varietal differences exist in the response of small grains to waterlog situations, but studies conducted under controlled conditions often obtain results contrary to what actually happens in the field. Predicting the effect of environmental stresses in the field is an inexact science.  The best information is that which is collected in field trials on or near your farm where the soil and environmental conditions are similar to yours.

 

Over several years, general observations of the winter wheat variety testing trials at the Washington State University – Mount Vernon location occasionally noted that a variety, located in a small waterlogged area of the field, may have had a better plant stand coming out of the winter than the varieties surrounding it.  So in the fall of 2014 a winter wheat nursery was planted in a low-lying area of a field (known for water ponding) to specifically identify the response of winter wheat varieties grown in waterlogged soil.

 

 

 

Nineteen varieties were planted on October 13, 2015 in a randomized complete block with four replications.  The seeding rate was approximately 100 lbs/acre, no fall fertilizer was applied, and the herbicide Diuron was applied preemergence two days later. During the two weeks prior to emergence, 3.25 inches of rain fell causing many of the varieties to emerge into standing water. On March 17 and April 2, a split application of NPKS was applied totaling 110 lbs N/acre. Maestro 2EC and Harmony Extra SG were applied at labeled rates for weed control.

 

The nursery was harvested on July 23 and the results were as follows:

 

 

 

This data are one year’s results under the field and environmental conditions experienced during the 2014-15 crop year.  However, the rankings seem to confirm the anecdotal observations of years past. This study will be continued for at least the next two years in order to obtain multi-year data and observe longer term varietal response to waterlogged field conditions.

 

 

For questions, contact Steve Lyon at slyon@wsu.edu.

 

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Images: Fall 2014 (left) and Fall 2015 (right).

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