Garfield County Cooperative Extension

North Central Oklahoma Research Station Tour

Rick Nelson Extension Educator, Ag/4-H

Plans for the 2016 North Central Research Station Wheat Tour located one mile west of Lahoma on US Highway 412 have been finalized for Friday, May 13. Registration will begin at 8:40 am. Coffee and doughnuts are sponsored by Oklahoma Wheat Growers for the first three hundred registrants that morning.  The trailers will load at 9:00 for 25 minute stops at four different locations hosted by various Oklahoma Agriculture Experiment Station researchers and Oklahoma Cooperative Extension Service specialists. Dr. Kim Anderson will be detailing when wheat prices will increase; Dr. Brian Arnall will be discussing nitrogen management; Dr. Josh Lufton will be presenting the latest on canola production; Dr. Brett Carver will be covering his wheat breeding program; Dr. Bob Hunger will provide a wheat disease update; Dr. Dr. Jeff Edwards will discuss the wheat variety trial on station; Dr. Randy Raper will lead a tour of the newly constructed Raymond Sidwell Research facilities; Dr. Tom Royer will provide an update on aphids on both wheat and grain sorghum; Dr. Jason Warren will discuss soil health after continuous cropping. Lunch will be provided by Farm Credit of Enid for those who RSVP to 580-237-7677 no later than May 9. A complete tour agenda is available at

 How efficiently can wheat use available water?

In regions where yield is limited by water, water is generally used more efficiently and yield potential can be calculated using a water-use efficiency coefficient. This is true for regions where growing season precipitation is generally less than about 13-15 inches, and precipitation distribution plays a very important role in determining the crop’s water-use efficiency.

Previous studies performed in the Southern Plains and other water-limited regions of the world, such as Australia, have shown that wheat can yield as much as 8.3 bu/acre for every additional inch of precipitation in the growing season when water is used most efficiently. This very effective use of water occurs only when precipitation is very timely and falls during critical periods for grain yield determination - such as stand establishment and tillering, spring greenup, and grain filling.

Although 8.3 bu/acre/inch is the potential transpiration efficiency of wheat, this extremely high water-use efficiency value only occurs when all conditions (management- and weather-related) lead to increased grain yields. This is very seldom observed under field conditions. For instance, any limitation due to suboptimal management, such as disease or pest incidence, nutrient deficiency, or weed pressure, will decrease the efficiency with which wheat uses the available water. Likewise, heat stress during later stages of grain filling will result in shriveled grains and will reduce the crop’s water use efficiency.

As a consequence, wheat water-use efficiency values in the 3 to 5 bu/acre/inch are more often observed under field conditions. A study looking at 11 site-years in

central Oklahoma resulted in water-use efficiency ranging from 2.9 to 4.8 bu/acre/inch, meaning that an average water-use efficiency of about 4 bu/acre/inch may be a fair number to use for wheat.

Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Oklahoma Cooperative Extension Service is implied.


Oklahoma State University, U. S. Department of Agriculture, State and Local governments cooperating.  Oklahoma State University in compliance with Title VI and VII of the Civil Rights Act of 1964, Executive Order 11246 as amended, Title IX of the Education Amendments of 1972, Americans with Disabilities Act of 1990, and other federal and state laws and regulations, does not discriminate on the basis of race, color, national origin, gender, age, religion, disability, or status as a veteran in any of its policies, practices, or procedures."


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