Southwest ND (8/25/11)

Rainfall in southwest North Dakota has been highly variable the past two weeks.  NDAWN indicated sites at Beach, Dickinson, Dunn Center, and Watford City all received less than a half inch of rain with Beach receiving the least in the region at 0.05 inches.  Bowman, Mandan, and Mott sites are all over an inch of precipitation with Mandan reporting 1.76 inches and Mott 1.57 inches for the two week period. 

                Winter wheat and canola harvest is nearly complete with some spring wheat fields beginning to be harvested.  Barley harvest is about half done. Second cutting of alfalfa hay is well underway. With spring wheat seeding occurring well into June we have received questions as to when this wheat will mature and be ready for harvest.  I can understand why the questions as the previous week, I saw some spring wheat fields that were just beginning to head. A wet spring caused may producers to delay seeding beyond the normal planting window for spring wheat. Growers will need to keep in mind the following. Standard maturity varieties require about 2400 growing degree days (GDD) from emergence to kernel hard stage (maturity) while early maturity varieties require about 2250 GDD. Both early and standard maturity varieties in the watery ripe stage need 755 GDD to reach kernel hard stage. As summer wanes the accumulation rate of GDD slows as temperatures fall. At Beach during the last half of August in a “normal” year GDDs accumulate at the rate of 30 to 35 GDDs per day.  From September 1 – 15 GDDs accumulated at the rate of 25 to 30 GDDs per day and the last half of September they accumulate at the rate of 20 to 25 GDD’s per day. 

So the question is when will wheat in the watery ripe stage mature?  The grower can take the days for the particular stage of development, in this case 755 GDDs needed for maturity and divide this number by the expected rate of accumulation for GDD, let us say 30.   The crop will need about 25 days.  If today is August 19 then by September 13 under normal temperature conditions the crop should mature.  The crop will require additional time in the field for grain to dry prior to harvest and storage. The time required to dry down is highly dependent upon humidity and temperature conditions at this point.

Additional information on growth staging can be found in “Use of Growing-Degree Days to Determine Spring Wheat Growth Stages,” EB37  by Baur, Fanning, Enz, and Eberlein. 

                This has been a year in southwest North Dakota where cover crops have been useful “tool” in soaking up the excess water.  A tour that maybe of interest to producers and others interested in agriculture is the Cover Crops, Coffee & Carmel Rolls tour Wednesday, August 31 at 8 am on the Ernie Holzemer Farm in Amidon.  This is a great opportunity to see a variety of cover crop options grown on clay soils and fine sands before heading out into the field for harvest.  You can also follow the progress of this cover crop demonstration seeded July 22 on the SW ND Agronomy Notes website  http://www.ag.ndsu.edu/swagronomynotes.

Roger Ashley - Area Extension Specialist/Cropping Systems

roger.ashley@ndsu.edu