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Soybean Iron Chlorosis Project 2001 Summary Report AGVISE Laboratories Benson, MN & Northwood, ND.
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Soybean Iron Chlorosis Project2001Summary Report AGVISE LaboratoriesBenson, MN & Northwood, ND
In cooperation with many of our customers, AGVISE Laboratories conducted a soybean iron chlorosis project in the summer of 2001 throughout the tri-state areas of MN, ND and SD. Sample locations were selected based upon chlorosis hot spots in grower fields throughout the region. Three soil samples were collected in each field, representing normal (healthy) soybean growth, moderately affected areas and a severely affected area. Only the severe and normal areas will be compared in this summary. Lab analysis consisted of measuring soil pH, carbonates and soluble salts. Field information included location, variety, plant height at time of sampling, date sampled, crop color, presence or absence of SCN on roots and row spacing. This summary will only look at plant height, pH, soluble salts and carbonates. Summary Plant Height: Dramatic difference between chlorotic and healthy areas. Soil pH: No difference between chlorotic and healthy areas. Soluble Salts: Major factor in contributing to soybean iron chlorosis. Carbonates: Major factor in contributing to soybean iron chlorosis. Note: SCN was a non-factor in the vast majority of fields sampled. Soybean Iron Chlorosis ProjectOverview
Soybean Iron Chlorosis Project Summer 2001: Agvise @ Benson, MN Fields Sampled: 79 Locations: 76 from S. MN, 3 from SD
Soybean Iron Chlorosis Project Summer 2001: Agvise @ Northwood, ND Fields Sampled: 26 Locations: 15 ND, 7 MN, 3 SD
Average Plant Heightat Sampling Time Soybean Iron Chlorosis Project Summer 2001: AGVISE @ Benson, MN Fields Sampled: 79 Locations: 76 from S. MN, 3 from SD
Average Plant Heightat Sampling Time Soybean Iron Chlorosis Project Summer 2001: AGVISE @ Northwood, ND Fields Sampled: 26 Locations: 15 ND, 7 MN, 3 SD
Average Carbonate (CCE) Soybean Iron Chlorosis Project Summer 2001: AGVISE @ Benson, MN Fields Sampled: 79 Locations: 76 from S. MN, 3 from SD
Average Carbonate (CCE) Soybean Iron Chlorosis Project Summer 2001: AGVISE @ Northwood, ND Fields Sampled: 26 Locations: 15 ND, 7 MN, 3 SD
Average Soluble Salts Soybean Iron Chlorosis Project Summer 2001: AGVISE @ Benson, MN Fields Sampled: 79 Locations: 76 from S. MN, 3 from SD
Average Soluble Salts Soybean Iron Chlorosis Project Summer 2001: AGVISE @ Northwood, ND Fields Sampled: 26 Locations: 15 ND, 7 MN, 3 SD
Average pH Soybean Iron Chlorosis Project Summer 2001: AGVISE @ Benson, MN Fields Sampled: 79 Locations: 76 from S. MN, 3 from SD
Average pH Soybean Iron Chlorosis Project Summer 2001: AGVISE @ Northwood, ND Fields Sampled: 26 Locations: 15 ND, 7 MN, 3 SD
Summary of the 2001Soybean Iron Chlorosis ProjectAGVISE Labs, Benson, MN • Fields Sampled: 79 • 76 from Southern Minnesota • 3 from South Dakota • Plant Height Averages • Severe Chlorosis: 6 inches • Healthy: 25 inches
Summary of the 2001Soybean Iron Chlorosis ProjectAGVISE Labs, Northwood, ND • Fields Sampled: 26 • 15 from North Dakota • 7 from Northwest Minnesota • 3 from South Dakota • Plant Height Averages • Severe Chlorosis: 7.5 inches • Healthy: 16.4 inches
Summary of the 2001Soybean Iron Chlorosis ProjectAGVISE Labs, Benson, MN • pH: • Severe Chlorosis: 8.0 • Healthy: 7.9 • Range of pH’s • Severe Chlorosis: 7.5 to 8.4 • Healthy: 6.5 to 8.4
Summary of the 2001Soybean Iron Chlorosis ProjectAGVISE Labs, Northwood, ND • pH: • Severe Chlorosis: 8.0 • Healthy: 8.0 • Range of pH’s • Severe Chlorosis: 7.9 to 8.3 • Healthy: 6.8 to 8.3
Summary of the 2001Soybean Iron Chlorosis ProjectAGVISE Labs, Benson, MN • Soluble Salts • Severe Chlorosis: 0.7 mmhos/cm • Healthy: 0.4 mmhos/cm • Range of Salts • Severe Chlorosis: 0 – 3.4 mmhos/cm • Healthy: 0 – 1.7 mmhos/cm
Summary of the 2001Soybean Iron Chlorosis ProjectAGVISE Labs, Northwood, ND • Soluble Salts • Severe Chlorosis: 1.0 mmhos/cm • Healthy: 0.4 mmhos/cm • Range of Salts • Severe Chlorosis: .30 – 2.45 mmhos/cm • Healthy: 0.1 – 0.9 mmhos/cm
Summary of the 2001Soybean Iron Chlorosis ProjectAGVISE Labs, Benson, MN • Carbonates (CCE) • Severe Chlorosis: 10% • Healthy: 5.4% • Range of Carbonates • Severe Chlorosis: 0.1 – 21% • Healthy: 0 – 20.5%
Summary of the 2001Soybean Iron Chlorosis ProjectAGVISE Labs, Northwood, ND • Carbonates (CCE) • Severe Chlorosis: 5.7% • Healthy: 1.9% • Range of Carbonates • Severe Chlorosis: 0.4 – 13% • Healthy: 0 – 11.7%
Blue Earth Brookings (SD) Brown (SD) Chippewa Cottonwood Douglas Grant Kandiyohi Lyon Nicollet Ottertail Pope Renville Sibley Stearns Stevens Swift Traverse Yellow Medicine Summary of the 2001Soybean Iron Chlorosis ProjectAGVISE Labs, Benson, MNLocations by County
% of Samples With Carbonates >5.0% (8600 Samples Tested in Highlighted Areas, Fall 2001) 8% 2% 3% 24% 33% 6% 3% 3% 56% 13% 26% 2% 11% 35% 3% 3% 12%
% of Soil Samples With Soil pH >7.3 (97,000 samples tested for pH in highlighted areas) 77% 80% 70% 54% 97% 44% 57% 92% 32% 69% 40% 20% 28% 62% 16% 25% 18%
Interpretation for Carbonates & Salts “Higher Salt Level” • Point Samples • If salts is higher than 0.7 and carbonate is higher than 5.0%, severe chlorosis is likely in that point. • Composite Field Sample • If salts are higher than 0.4 - 0.7 and carbonate is higher than 2.5-3.0%, areas of the field are likely to have chlorosis.
Interpretation for Carbonates & Salts “Low Salt Levels” • Point Samples • If salts is less than 0.4 and carbonate is higher than 8.0%, chlorosis is likely at that point. • Composite Field Sample • If salts are less than 0.4 and carbonate is higher than 5.0%, areas of the field are likely to have chlorosis.
Future of Carbonate and Salt Soil Test • Seed companies testing their variety plots • Varieties rated by carbonates & salts • Information used for better management • Diagnostic tool to investigate spots in fields • Variety selection
Factors “Known” to Increase Potential for Iron Chlorosis • Soluble Salts • Carbonates • Excessive water • Cool Temperatures • High pH???????
Iron Chlorosis Facts • Carbonates and Salts are two important factors affecting potential for iron chlorosis. • Carbonates are a fixed soil property • Salts can be reduced with drainage • Soil pH is not a good indicator of potential iron chlorosis. • Knowing the carbonate and salt level can help growers choose fields to plant soybeans. • Knowing the carbonate and salt level can help explain problem areas.