Using Calcium Sulfate as a Soil Management Tool

Agricultural Uses of Gypsum and other FGD Materials Workshop

September 12-14, 2006

Who is Soil Solutions? • Formed company in May 2002• Owners are Kevin Heck, Dale Ronfeldt, Bob

Hecht; based out of Holstein, IA• Contracted with PGLA-1 to market their calcium

sulfate as “PRO CAL 40” and the biomass as NUTRABIO.

• Trucking Co., Consulting Co., Marketing Co., Farming Operation.

• Market PRO CAL 40 in seven states.• Currently employ 14 people.

Where are the Sources of Calcium Sulfate?

“PRO CAL 40” As Pure As Snow!!

Liming should be the start of any Fertility Program on a low pH soil.

Calcium Sulfate should be the start of any Total Soil Management Program. Maintain Good Air-Water Exchange

Brings more microbial life back into the soil

Reduces Soil Erosion

“PRO CAL 40”

• Contains 99.5% Gypsum & <0.5% lactic acid• pH of Fresh material is 3.2-4.2• pH of Stockpiled material is 6.3-7.6• Moisture will range from 25% down to 10%.• Particle size = 160 microns • Conservatively, each ton will last 3 years (500-

700#/year) depending upon moisture.

Challenges & Obstacles

• Derivative of Corn Processing• There must be something hazardous in it?

• Farmers expect it to be free

• Supply is driven by lactic acid production, not by orders taken.

• High Rates are needed for best response• Freight is a major expense.

• More work involved.

• Retailers understanding margin/acre vs. margin/ton.

Challenges & Obstacles

• Granulized Calcium Sulfate has been marketed at low rates and in less responsive soils—gotten a bad name.

• Research $$ are limited so university data has been difficult to generate. Most university research has been done using low rates.

• A lack of understanding of soils and soil chemistry by producers and advisors. (ie. Does high pH mean alkali?)

• Adoption of new practices in agriculture takes time. Driven by commodity prices/econ. return.

We start applying in the fall after harvest……

Continue through winter……..

And finish in the spring when planting begins…..

Using Calcium Sulfate to Amend Soils

We use soil tests to determine responsiveness and the proper rate.

Recommendation Formula:For Magnesium Amendment:

[((% Mg-22)/100 x CEC)) X 2000] + (pH-7.2) X 2000 = # PRO CAL 40

OR

[(((PPM Mg/120) - (0.22 X CEC)) X 2000) + ((pH -7.2) X 2000)] = # of PRO CAL 40

For Sodium Amendment:

[(((PPM Na/230) - (0.02 X CEC)) X 2000)) + (((PPM Mg/120) - (0.22 X CEC)) X 2000)))] = # of PRO CAL 40

If Excess Lime rating is medium or high, rates greater than 1 ton/A will need to be considered.

Understanding Irrigation Water Analysis

Alkali Soil = Sodic Soil

David City, NE

Cook, NE

Changes in Soil Test LevelsAlkali Soil

One Year Following Application of PRO CAL 40

P1 P2 K pH Na %Na %Mg %Ca Zn

Before App. 7 52 265 8 337 6.6 44.7 45.7 1.4

After App. 19 55 379 6.4 68 1 34.2 52.5 2.2

Luton, IA

Effect of Bicarbonate on Iron Concentration in Corn Seedlings

Bicarbonate Concentration, meq/l Plant Part 0 5 10 20

Iron Conc. (PPM)

Young Leaves 80 57 38 32

Old Leaves 140 100 46 43

Roots 3410 2560 1770 13801997 Journal of Plant Nutrition 20: 1731-

1753

Effect of Increasing Bicarbonate Concentration on Corn Seedling Roots

0

0.5

1

1.5

2

2.5

3

3.5

4

2 4 6 8

Days

Fre

sh

Wt.

(g

ram

s)

20

10

5

0

Soil dispersion is mainly caused by highly hydrated Na+ and Mg2+ attracted to the surface of clay particles as exchangeable cations.

Mg2+Ca2

+

Clay particle

Water

1.5 ton/A Untreated

Producer reported a 30 bushel response

Percolation Rates Increase With Calcium Sulfate

Depth of Water Percolation

Treatment Standing after 24 hrs., In. ml/24 hrs.

Check .50 86

Sulfur, 1 ton .23 86

CaSO4, 1 ton .18 190

Ca SO4, 5 tons .15 280

McGeorge et al. (1956), Irr. Plots; Impermeable soil.

33.05%40.71%

60.87%74.39%

Control

Gypsum Material

0.560.59

0.7

1.81

0.1 0.14 0.3 0.510

0.4

0.8

1.2

1.6

2

Steady State Infiltration Rate,

Inches/hr

Percent Soil Calcium

Effect of Calcium on Infiltration Rates

Control

Gypsum Material

Purdue University

Westboro, MO

pH and Aluminum Levels

Depth pH Aluminum,ppm % Ca

0-4” 4.6 35 34.6

4-8” 4.0 163 13.9

(189 ppm)

Northern Nebraska

In SummaryUsing calcium sulfate in many types of soil

conditions will benefit production. The adoption of “precision agriculture” has been

of value in promoting soil amendments such as lime and calcium sulfate.

The value of lime in agricultural production has taken 20+ years in many areas. Realizing the value of calcium sulfate will also take time.

Education and demonstration is important in effectively marketing calcium sulfate.

PRO CAL 40

Soil Solutions, LLC

303 Lamp Kastner Drive

Holstein, IA

(712) 368-2185