Gypsum Additive
to Improve Soil Condition, Moisture Infiltration,
and Crop Yields for Asotin County Sodic Soils
Doug
McMillan
with WA Conservation Commission, Brian Sangster, Gary Delaney,
Baird Miller, Jim Schroeder
Objective
To test the effectiveness
of the soil amendment gypsum in improving moisture infiltration, surface
texture, soil quality parameters, and crop yields for sodic soil conditions.
Location: Asotin
Co., WA - Cloverland
Average annual precipitation: 13 inches
Soil: Weissenfels-Nims silt loam 3-8%, with a depth of only 2'
Rotation: Winter wheat (Stephens in 1994)-fallow
Treatments
Check - no application
Gypsum at 1/2 T/ac
Gypsum at 1 T/ac
Comments
The field was chiseled
in the fall of 1992 following winter wheat harvest. In the spring of 1993
Roundup was applied and then in May the field was chiseled again. During
the summer fallow the field was cultivated and then rod weeded twice before
seeding. Fertilizer was applied during the summer including 45 lbs N/ac
and 10 lbs S/ac. The gypsum treatments were applied with a 40' barber
type spreader during the summer fallow and then cultivated to incorporate
the gypsum. The field was seeded with a press wheel drill on 10"
spacing on October 25, 1993. Starter fertilizer was banded with the seed
including "Super Starter" (micronutrient product with Ca, Cu,
Zn, Mg) 8-10 lbs P/ac and boron. The following spring micronutrients and
Uran were added to the herbicide application.
Data
Winter
wheat yield, bu/ac
| Treatment |
Rep 1 |
Rep 2 |
Rep 3 |
Rep 4 |
Average |
|
Check |
36.3 |
26.5 |
35.5 |
35.4 |
33.4a |
|
1 T |
28.7 |
36.4 |
40.4 |
35.2 |
35.2a |
|
1/2 T |
30.3 |
35.1 |
35.1 |
37.8 |
34.6a |
|
LSD (5%) |
|
|
|
|
7.25 |
|
CV |
|
|
|
|
12.2% |
Conclusion
Under the droughty
conditions of the trial no yield differences were found due to the applied
gypsum. The winter wheat crop looked good in the spring but showed moisture
stress during June. More time is required to evaluate gypsum's impact
on soil quality parameters and crop improvement.
|
