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May 23, 2011 Agriculture Column

Howdy!!!!

Well, I am not sure if we lucked  out or not.  Any rain is too much, but many forecasts indicated a good chance of more rain than what we received.  Some might say give us much more to get the process moving downstream and others are just thankful that we did not to allow some field work.  The field work is very different in the county this spring.  The northeastern part of the county did not receive the snow that the Devils Lake area received thus had less problems this spring.  There was still problems but that corner of the county was definitely drier than the rest of the swamped county.

 

Small Grain Development and Growth Staging

 

Early Growth Staging in Small Grains

Growth stage scales have been developed and are commonly used by researchers when describing experimental methods and results in scientific publications but less so in communicating recommendations to farmers.  Though the timing of early-season management recommendations are most commonly based on leaf numbers or other visible characteristics of the plants, Table 1 lists the most commonly used growth staging scales and highlights some of the key growth stages in wheat.  

 

Predicting Leaf Stages in Small Grains

Sometimes it is useful to be able to estimate or predict when a certain growth stage will be reached.  Plant development is closely correlated to the accumulation of heat units or Growing Degree Days (GDD), much more so than calendar days.  Based on plant emergence and historic temperature trends, you can fairly accurately predict when a crop will reach a certain developmental stage.  Growing degree days are readily available for a number of locations in North Dakota using the NDAWN website.

Except for the first leaf which requires only 70 GDDs, wheat requires about 140 GDDs and barley about 100 GDDs to produce a leaf.  The actual number of GGDs required can vary between varieties, but these values will give estimates that will be accurate enough for most applications.  Be sure to use GDD that were calculated for small grains, which use a base temperature of 32 degrees.  Other base temperatures are used for corn and sunflower and certain pests. 

 

Table 1. Comparison of  terminology of  various growth stage systems at certain key growth stages, and  approximate growing degree day (GDD) accumulation needed to reach that stage in wheat (based on the 32 degree F base temperature)(shaded area = after emergence)

 

Wheat

Stage

Staging System

Accumulated GDD Needed

Feekes

Zadoks

Haun

Emergence

----

09

0.0

180 to emerge

1st leaf

1

10

0.5-1

70 after emergence

Tillering

2

21

3.5

360 after emergence

Jointing

6

31

6.3

715 after emergence

Boot

10

45

10.5

1360 after emergence

Anthesis

10.51

65

11.4

1571 after emergence

 

Further information about growth staging is available at the following web sites: 

For wheat: http://www.extension.umn.edu/distribution/cropsystems/dc2547.html

For barley: http://www.extension.umn.edu/distribution/cropsystems/DC2548.html

 

Growing degree day information associated with the NDAWN weather stations may be found at:  

http://ndawn.ndsu.nodak.edu

 

 

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