Transcript Dolomite or Calcite Aglime: What’s Best?

Dolomite or Calcite Aglime:
What’s Best?
Tim Wagar, Regional Extension
Educator
Definition of Ag Liming Material
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Contains Ca and Mg compounds that can
neutralize soil acidity
Limestone
Quicklime
Hydrated lime
Marl
Shells
Byproducts
Agricultural Limestone
Mixture of - Calcite CaCO3 and
Dolomite CaCO3 + MgCO3
 Calcite - 40% Ca and 0-0.6% Mg
 Dolomite – 21.7% Ca and 13.1% Mg
 Ca:Mg ratio of crops is closer to that of
dolomite
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Agricultural Limestone Quality
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Laboratory measurement of chemical effectiveness
– % Total Nuetralizing Power (% TNP)
Particle size from crushing/grinding – (Fineness
Index)
(Fineness Index) X (% TNP) = % ENP
% ENP X 2000 lbs X % Dry Matter =
Pounds of Effective Neutralizing Power/ton
Liming Materials – Winona Co., 1991
ENP
Lime
Applic. pH
lb/acre
Check
6.3
Dolom 3594
6.4
Calcite 2988
6.7
Dolom 3594
6.6
+400 lb
*4.33 “Ideal Ratio”
Exch
Exch Ca/Mg
Ca
ppm
2412
2463
2791
2414
Mg
ppm
292
343
310
419
Ratio*
8.26
7.18
9.00
5.77
Liming Materials Yield – Winona Co., 1991
Lime
Check
Dolomite
Calcite
Dolomite + 400
lb Mg/acre
*2 cuttings
ENP
Applied
lb/acre
3594
2988
3594
Yield*
Ton D.M./acre
2.6
2.6
2.5
2.6
Aglime Effects on Alfalfa,
Rochester Center Plots - 2000
ENP Applied (lb./acre)
Lime
Mg
Source Applic.
0
lb./acre
Calcitic
0
1.82
Calcitic 300
Dolom
0
Dolom
300
Ca:Mg Ratio – 4.1
1750
3500
ton D. M./acre
2.37
2.24
2.09
2.36
2.30
2.30
5250
2.29
2.46
Aglime Effects on Alfalfa - 2001
ENP Applied (lb./acre)
Lime Mg
Source Applic.
0
lb./A
Calcite
0
3.23
Calcite
Dolom
Dolom
300
0
300
1750
3500
ton D.M./acre
3.63
3.62
3.73
3.61
3.62
3.72
5250
3.53
3.51
Aglime Effects on Alfalfa - 2002
ENP Applied (lb./acre)
Lime
Mg
Source Applic
lb./A
Calcitic
0
Calcitic 300
Dolom
0
Dolom
300
0
3.92
1750
3500
ton D.M./acre
4.08
4.19
4.04
4.08
4.04
4.11
5250
4.26
4.2
Summary
No agronomic evidence that Mg levels in
dolomite lime are detrimental to alfalfa
 Should be more concerned about inducing
grass tetany in cattle from forages grown on
soil with the exclusive use of calcitic lime
 No agronomic or economic reason to
“import” purported calcitic lime
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