Subsoil moisture levels from 2011, 2012

November 18, 2020 2:44 PM
Blog Post

The question has been asked 'how does the subsoil moisture levels from the fall of 2020 compare to other dry falls'.

 A look back shows the following levels of fall subsoil moisture from 2011 and 2012 - for the six sites where I survey soil moisture in northwest Iowa.

Rainfall - for the sites at or near the sites below - from November 1, 2011 to April 21, 2012 was 6.5 to 7.0 inches.  

The amount of subsoil moisture recharge was around 3 to 4 inches (table 1) - so less than the rainfall that occurred during that time period.  I forget the specific weather conditions - but the soils may have been frozen when some of that rainfall occurred.  And therefore the rainfall did not contribute to subsoil moisture.  

 

Table 1. County subsoil moisture – fall 2011 and spring 2012.                                                                                                                                                                                  

                        County                                                            plant available moisture,

                        Fall                                                                  inches

County            average, in.     location                                   Nov. 1, 2011   April 23, 2012

 

Dickinson        5.7                   Spirit Lake                              1.4                   5.2

Emmet            5.9                   Estherville                               -

Clay                5.7                   Rossie                                     5.0                   7.8

Buena Vista    6.0                   Newell                                    -

Pocahontas      6.0                   Rolfe                                       3.3                   7.0

Sac                  5.9                   Schaller                                   -                       7.8

 

Rainfall - for the sites or near the sites below - from November 1, 2012 to April 23, 2013 was 5.0 to 6.0 inches.  The exception was Storm Lake - which only had 3.8 inches for this time period. 

Another way to view it - there was 7.0 to 9.0 inches of rain from September 1 of 2012 - or about the time of crop maturity - until April 23 of 2013.  Again - the exception was Storm Lake - which only had 5 inches during this time period. 

Keep in mind this soil moisture recharge occurred before the spring of 2013 gained the reputation it was about to gain.  

Table 2. County subsoil moisture – fall 2012 and spring 2013.                                                                                                                                                                                 

                        County                                                            plant available moisture,

                        Fall                                                                  inches

County            average, in.     location                                   Nov. 9, 2012   April 26, 2013

 

Dickinson        5.7                   Spirit Lake                              3.9                   9.5

Emmet            5.9                   Estherville                               1.4                   6.4

Clay                5.7                   Rossie                                     5.8                   10.3

Buena Vista    6.0                   Newell                                    4.3                   10.3

Pocahontas      6.0                   Rolfe                                       3.2                   7.2

Sac                  5.9                   Schaller                                   2.9                   8.9

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Paul Kassel Field Agronomist in NW Iowa

Paul Kassel provides research based crop production information to area farmers and agribusiness. Educational programs are available for farmers, agribusiness, pesticide applicators, and certified crop advisors.

Areas of expertise include soil survey, crop production, soil ferti...