This study evaluated the effectiveness of applying gypsum at different rates (0, 300, 500, 1000 lbs/acre) on water infiltration rates and crop yields on poorly drained soils in northwest Missouri over four years. The application of gypsum did not increase water infiltration rates or crop yields of corn compared to the untreated check. Educational outreach events were held to communicate the research results to over 250 local growers and discourage the use of gypsum based on the findings.

1. Evaluation of The Effectiveness of Gypsum Applications on Water Infiltration
Rates and Crop Yield
Flanary,*W.E.1;Chapple, R.W.2 Crawford, J.J.W.3
Graves Chapple 1Agronomy Specialist, University of Missouri Extension, Oregon, Mo 64473
Agricultural
Experiment Station 2Retired Ag Engineer, University of Missouri Extension, Rockport, Mo 64482
3Farm Coordinator, University of Missouri Extension, Rockport, Mo 64482
Abstract
Gypsum is promoted to increase water infiltration and increase crop yields on poorly drained soils in northwest Missouri. A gypsum rate of a check, 300, 500 and 1,000 pounds of commercially sold gypsum was applied to a randomized complete block design
experiment. Typical rates are 300 pounds of material per acre because of cost. Rates were increased to 1,000 pounds per acre to determine if a higher rate would provide the desired impact. Crop yields were measured along with water infiltration rates. The
application of different rates of gypsum did not result in an increase of water infiltration rates compared to that of the check. Crop yields were measured for four years and gypsum did not significantly increase crop yields. The educational impact of this experiment
resulted in growers discontinuing their use of the product. The research results were communicated to growers during the Graves-Chapple Farm field days with attendance in 2006 of 146. Data were published in the Graves-Chapple Farm annual reports of 2004 and
2005. Copies were distributed to 250 growers per year. Summary data were presented in Agricultural update meetings to growers in 15-county Northwest Missouri Extension region in 2007.
Introduction Table 2. Effect of Gypsum Application on 2004 Corn Yield Table 4. Effect of Gypsum Application on 2006 Corn Yield
Gypsum is marketed to increase water infiltration rates 200
200
resulting in increased crop yields. Gypsum is used to 180
180
correct saline and sodic soils in Oklahoma and Kansas
160 160
(Lamond et. al., 1992; Zhang, et al, 2009).
Yield, bu. per(Bu/A)
140
Corn Yield acre
140
Yield,bu per acre
120
Yield, bu. per acre
120
Objectives 100
80 100
To determine if the application of gypsum at different rates 60 80
would increase water infiltration rates and crop yields. 40
60
20
Educate growers the about the use of gypsum. 40
0
0 300 500 1000
20
Gypsum, lbs per acre LSD .05 = NS
Materials and Methods 0
0 300 500 1000
Location: Graves Chapple Resaarch Farm, Corning, Mo. Gypsum, lbs per acre LSD .05 = NS
Soil: Salix Silty Clay Loam.
Treatments: 0, 300, 500 and 1,000 pounds of gypsum.
Table 5. Effect of Gypsum Application on 2007 Soybean Yield
Randomized complete block with five replications. 80
70
Results and Discussion 60
Yield, bu. bu per acre
Yield, per acre
50
The application of different rates of gypsum did not increase 40
water infiltration rates (Table 1). Also, the use of gypsum did 30
not increase corn yields in year one (Table 2).
20
No significant differences in yields were measured in 10
soybean, 2005 (Table 3); corn yield, 2006 (Table 4) and 0
soybean yield, 2007 (Table 5). 0 300
Gypsum, lbs per acre
500 1000
LSD .05 = NS
Missouri soils do not have the characteristics that would
benefit from the application of gypsum. The application of
gypsum would benefit soils where large amounts of sodium
are absorbed. The application of gypsum is used to loosen
the sodium from the soil particles so it can be leached. Summary
The application of gypsum did not increase infiltration rates
and crop yield.
University of Missouri Extension provided applied research
Table 1. Effect of Gypsum Application on Water Infiltration and education to more than 850 growers over a four years.
45 Table 3. Effect of Gypsum Application on 2005 Soybean Yield Area growers discontinued the use of gypsum.
40 80
35 70
Literature Cited
Infiltration, minutes
Infiltration, minutes
30 60
Soybean Yield (Bu/A)
Yield, bu. Per acre
25 22.5 50 Lamond, R.E., D.A. Whitney, 1992. Management of Saline
20 17.25 40
and Sodic Soils, MF-1022, Kansas State University
15 12
14.75
30
Agricultural Experiment Station and Cooperative Extension
10 Service.
20
5
10 Zhang, H. 2009. Reclaiming Slick-Spots and Salty Soils,
0
0 PSS-2226, Oklahoma Cooperative Extension Service.
0 300 500 1000
0 300 500 1000
Gypsum, lbs per acre LSD .05 = NS
Gypsum, lbs per acre LSD .05 = NS