Calcium Products - Andrew Hoiberg, Ph.D.
Calcium Product 98G


Andrew Hoiberg, Ph.D.

Andrew Hoiberg, Ph.D.

SuperCal SO4 on Soybeans with White Mold

Plot Map


• Planted soybeans (Stine 2500) on May 16, 1998 at 50 lbs/A
• 20 acre field
• 5 Replications
• 2 Treatments

CaSO4 Soybean with White Mold Yield Map 1998



The average of the areas receiving SuperCal SO4 yielded 48.4 bushels, the areas that did not get treated averaged 38.6 bushels, which was a difference of 9.8 bu/A. At $10 soybeans that is a return of over $65 per acre.


SuperCal SO4 and Nitrogen Utilization on Corn

SuperCal SO4 was applied to a high pH 7.5 field with corn at Cedar Falls, Iowa in 2002. Four replications of six treatments were arranged in a randomized complete block design. This was an excellent year for corn and good yields were noted throughout the area. A moisture stress period was noted in midsummer, but timely rains contributed to good yields.

Yields increased from 207.6 bu/A for control to 221.8 bu/A with 300 lbs/A SuperCal SO4 applied at planting. A base rate of 140 lbs/A nitrogen (N) was applied as anhydrous ammonia to soybean ground, considering a rough credit 50 lbs. N/A for the contribution of soybeans in the rotation. However, the addition of 80 lbs N/A at sidedress time resulted in only a 2.1 bu/A yield increase over the 140 lbs N/A areas. One could speculate that the maximum nitrogen response rate had been reached with 140 + 50 + 80 = 270 lbs/A N with soybean credits. Yields did not increase with 300 lbs/A SuperCal SO4 plus 80 lbs N/A at sidedress time, and it is speculated the plants may have grown too much prior to the moisture stress period. Early application of SuperCal SO4 at planting may have contributed to promoting plant growth at the right time, and resulted in increased partitioning of photosynthates into the kernel.



SuperCal SO4 with Field Corn

Project Code: 99-61240
Location: Hollandale, MN
Sponsor: Calcium Products, Inc.
By: Agri-Growth, Inc.



• Field corn (Novartis NK3030) planted May 29, 1999 at 35,000 SPA
• Treatments applied prior to planting
• Treatments:
       o SuperCal SO4 at 50 lbs/A (banded 6" deep) and Urea at 30 lbs/A actual N
       o SuperCal SO4 at 50 lbs/A (banded 6" deep) (only)
       o Urea at 30 lbs/A & actual N (only)
       o Untreated control
• Five replications




Yield bu/A

SuperCal SO4 and

50 lbs/A
30 lbs/A actual N

151.2 a

Urea (only)

30 lbs/A actual N

148.7 b

SuperCal SO4 (only)

50 lbs/A

145.5 bc

Untreated Control


141.3 c

Yield means followed by the same letter do not significantly differ (P=.05 Duncan's)


SO4 on Corn and Soybean

A two treatment trial where two treatments are paired together in adjoining strips is a type of a randomized complete block design. This trial had ten paired strips, each containing one strip each of the two treatments.





Corn Harvest Analysis

This type of trial can be analyzed using a t-test, which determines if numerical difference between treatments are legitimate. Following is a "cookbook" approach to analyzing the data from a trial with up to ten double strips, each containing one strip each of the two treatments. The second and third columns are labeled "yield," but any type of data can be analyzed this way.


The difference between the two treatments is given in Cell 3. The number in Cell 8 is called the "t value" (be sure to record it without the negative sign, if Cell 3 us a negative number, that is, if treatment B has a higher yield than treatment A). We assess whether the difference between treatments (Cell 3) is real or whether it's due to random chance using the following test:

We're 90% sure the treatments really differ if Cell 8 is larger than: 1.860

We're 95% sure the treatments really differ if Cell 8 is larger than: 2.306

Therefore, the statistical confidence that there is a difference between these treatments is greater than 95%. So, the plots treated with  SO4 produced a significantly higher corn yield than those that were not treated.


Soybean Yield Analysis


For the soybean analysis, the statistical confidence appears to be less and the resulting conclusion is that the difference is not explained by the statistical model, meaning that there is not a real difference between the two yield values, despite the roughly 3 bu/A increase when using gypsum.


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