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Lime Recommendations with 1 M KCl soil pH and Sikora buffer pH. 10 mL Sikora buffer. 10 mL M KCl. 10 cm 3 soil. 1 M KCl soil pH. Sikora buffer pH. 1. Advantages. 1. Solves problem with low pH in fall. 2. Accounts for pH buffer capacity of soil. 2. 3. 4.
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Lime Recommendations with 1 M KCl soil pH and Sikora buffer pH 10 mL Sikora buffer 10 mL M KCl 10 cm3 soil 1 M KCl soil pH Sikora buffer pH 1
Advantages 1. Solves problem with low pH in fall 2. Accounts for pH buffer capacity of soil 2
Average pH for Southeastern KY counties D1 D0 D0 D1 D3 D3 5
cmol/kg H+ 0 1 2 3 4 5 6 8 Adams-Evans 7 Mehlich SMP 6 pH 5 Typic Fragiudalf silt loam 1 M KCl soil pH CEC = 7 cmol/kg 4 0 1 2 3 4 5 6 cmol/kg OH- 6
cmol/kg H+ 0 1 2 3 4 5 6 8 7 SMP 6 pH 5 Typic Fragiudalf silt loam 1 M KCl soil pH CEC = 7 cmol/kg 4 0 1 2 3 4 5 6 cmol/kg OH- 7
Lime response curve Soil pH Buffer pH 1 M KCl soil pH Lime added Mechanistic approach Empirical correlations Buffer pH Lime required 8
Lime Recommendations with soil pH and soil-buffer pH 5.6 Soil-water pH 6.8 Soil-buffer pH 9
Should the same amount of lime be recommended for the two soils below? Soil 1 Soil 2 5.6 Soil-water pH 4.5 6.8 Soil-buffer pH 6.8 11
Kentucky LR table based on soil-water pH and Sikora buffer pH 12
Double-buffer method for Lime Recommendations 5.2 Soil pH 5.4 Soil-buffer pH 1 These two used to assess pH buffer capacity of soil 6.4 Soil-buffer pH 2 13
cmol/kg H+ 0 1 2 3 4 5 6 8 7 SMP 6 pH soil- water pH 5 SMP with initial pH of 6 4 0 1 2 3 4 5 6 cmol/kg OH- 14
cmol/kg H+ 0 1 2 3 4 5 6 8 7 Soil-buffer pH = 6.4 6 pH Sikora = SMP 5 1 M KCl soil pH = 4.3 4 0 1 2 3 4 5 6 cmol/kg OH- 15
Target pH = 5.5 Added alkalinity (cmol/kg) 16
Lime response curve from 1 M KCl soil pH and Sikora buffer pH Titration of soil with KOH in 1 M KCl Titration of soil with KOH in water 17
1:1 line 18
Correction factor for long-term field neutralization Fig. 4 c) LR = Alkalinity to pH 5.5 x Correction Factor 1:1 line Current KY LR ---------------------------- 1 M KCl soil pH and Sikora buffer pH LR LR using 1 M KCl soil pH and Sikora buffer pH (cmol/kg) 19
Current KY LR SMP double buffer LR Correction factor 20
Lime Recommendations with 1 M KCl soil pH and soil-buffer pH 4.6 5.5 soil-water pH 1 M KCl Soil pH = 6.8 Soil-buffer pH 23
1 M KCl soil pH and Sikora buffer pH for Lime Recommendations Advantages 1. Solves problem with low pH in fall 2. Accounts for pH buffer capacity of soil 3. Background electrolyte good for quick and stable pH reading 24
Soil-buffer pH = 7.0 Target pH = 5.5 1 M KCl soil pH = 4.0
Current LR table based on soil-water pH and Sikora buffer pH
New LR table based on 1 M KCl soil pH and Sikora II buffer pH
cmol/kg H+ 0 1 2 3 4 5 6 8 7 SMP 6 pH Buffer pH 5 4
cmol/kg H+ 0 1 2 3 4 5 6 8 7 SMP 6 pH “Lime response curve” 5 4 0 1 2 3 4 5 6 cmol/kg OH-
cmol/kg H+ 0 1 2 3 4 5 6 8 Lime requirement for target pH of 6.5 7 SMP 6 pH 5 SMP with initial pH of 6 4 0 1 2 3 4 5 6 cmol/kg OH-
cmol/kg H+ 0 1 2 3 4 5 6 8 Lime requirement for target pH of 6.5 7 ? SMP 6 pH water pH 5 SMP with initial pH of 6 salt pH ? 4 0 1 2 3 4 5 6 cmol/kg OH-
1 M KCl soil pH and Sikora buffer pH for Lime Recommendations Advantages 1) Mechanistic approach for soils of varying buffer capacity 2) Solve problem with lower than expected soil pH during dry falls
Soil-buffer pH = 6.2 Lime response curve 1 M KCl soil pH = 4.3 (2 cmol/kg alkalinity = 1 ton/acre CaCO3)