Weekly Crop Water Use Report -- Example Sheet

Sherburne Soil & Water Conservation District Ph: (763) 241-1170 ext.3

Allowable Soil Water Deficit specifies the maximum amount of soil water to be used from the rooting zone before scheduling the next irrigation event to reduce the probability of incurring crop moisture stress.

Example → Allowable Soil Water Deficit = 60%(0.60)

Available water capacity in root zone = 3.5 inches

0.60 X 3.5 = 2.1 inches

 

 

 

 

 

Rain Reports

7 day rainfall total .45 inches

April 5.91"       August 2.49"
May 3.39"       September
June 2.29"       October
July 1.06

* Rainfall from Crescent Lake Climate Station,
Clear Lake.
Irrigation Information
Crop:

Corn

Potatoes

Soybeans

Kidney Beans
Planting/Cutting Dates:

4/23/01

4/17/01

5/15/01

5/28/01
Stage of Growth:

1/2 milk

harvest

full maturity

harvest
Allowable Depletion(%):

60%

60%

 70%

 60%
* ET Conversion Factors:
* Percentage of Potential ET being used by crop



Rate that water vapor would be lost from densely vegetated soil if soil water content were kept at an optimal level. Potential ET (PET) varies in relation to changes in:

                                      ·temperature
                                      ·wind speed
                                      ·relative humidity
                                      ·solar radiation
An estimate of plant water usage, calculated by adjusting the potential ET for crop type and stage of growth.

 


Climate Information
          Solar Average
  Daily Temps Humidity Radiation  Wind

Day

 High (F) Low  (F) High(%) Low(%) (Langleys) (MPH)
09/17/01

67

 67 99 71 145 1
09/18/01

64

 64 100 76 115 1
09/19/01

67

 		67 100 71 146 1
09/20/01

62

 		62 100 86 133 1
09/21/01 70 70 100 56 315 2
09/22/01 57 57 100 82 89 2
09/23/01 57 57 98 53 221 4

Daily Evapotranspiration (ET's)

Actual Crop Water Use (inches)

        Kidney
Potential Corn Potatoes Soybeans

Beans
ET ET ET ET ET
0.05

0.04

 0.03 0.02 0.01
0.04

0.03

 0.02 0.02 0.01
0.05 0.04 0.03 0.02 0.01
0.04 0.03 0.02 0.01 0.01
0.08 0.06 0.05

0.03

 		0.02
0.02

0.02

 0.01 0.01 0.01
0.06

0.05

 0.03 0.02 0.02
Measurement based on the mean daily air temperature; within the range of 50º F to 86ºF.
4 Day Avg.
7 Day Total
Running Total
0.05 0.04 0.03 0.02 0.01
0.34 0.26 0.19 0.12 0.09
23.64 15.57 16.24 13.97 11.99

 

Growing Degree Days (GDD’s 50/86)
    Current GDD's Normal GDD's Departure from Normal
Starting April 1 2429 2356 73
Starting May 1 2303 2234 69

 

Used to calculate the current growing degree days.
  Daily GDD's
09/17/01 10
09/18/01 7
09/19/01 9
09/20/01 6
09/21/01 10
09/22/01 4
09/23/01 3
Accumulated growing degree days from the start of the growing season to date; used to estimate the growth and development of plants and insects during the growing season.

Call Sherburne SWCD at (763) 241-1170 ext. 3 to request a weekly summary of the ET’s.