Corn Product Response to High pH Soils

Trial Overview

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  • High pH soils can be caused by several different factors including excess lime, high soluble salt concentration, and/or high nitrate-nitrogen concentration. For these trials, the source of the high soil pH levels is excess lime from high calcium carbonate concentration in the soil parent material. This situation is very common across much of Western Kansas and Eastern Colorado on eroded sidehills and cut areas in fields.
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  • Crops growing in high pH soils may express iron deficiency chlorosis (IDC). IDC symptoms include interveinal chlorosis, overall pale-yellow color, and stunted growth. Also, the availability of key nutrients to the crop may be reduced in high pH soils.
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  • Corn seed products often respond differently in high pH soils as some products are more tolerant to these conditions while others may be susceptible. IDC tolerant seed products are less likely to express IDC symptoms.
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Research Objective

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Location
Soil Type
Previous Crop
Tillage Type
Planting Date
Harvest Date
Potential Yield
Planting Rate
Bethune, CO
Silt loam
Soybean
 
05/11/2016
10/17/2016
250 bu
30,000 seeds
Burlington, CO
Silt loam
Corn
 
05/09/2016
10/18/2016
250 bu
30,000 seeds
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Site Notes:

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17 DEKALB® corn products were planted in two separate blocks in the same field at each location. One block had a near-neutral soil pH and one block had a high soil pH. Each block contained five replications of the set of corn seed products. Soil pH was determined with the use of a Veris® Technologies machine and soil sampling. A visual color rating was taken at the V8 (8 leaf collars) growth stage. The color scale ranged from a very dark-green which was rated 3 to a pale-yellow color that was rated 7. These ratings were then grouped into three separate product placement recommendations: Highly Recommended, Recommended in Most Situations, and Use with Appropriate Management for high pH soil field conditions.
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Understanding the Results

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Figure 1. DEKALB® brand blend recommendations for 
near-neutral soil pH and high soil pH conditions.
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Figure 2. IDC symptoms (left) and IDC tolerant products (right)
in high pH soils.
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  • All seed products did not exhibit any visual differences in IDC symptoms when planted in near-neutral soil pH conditions.
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  • DEKALB® DKC45-65RIB, DKC46-36RIB, DKC47-47RIB, DKC51-38RIB, DKC59-50RIB, DKC61-88RIB, DKC63-55RIB, DKC63-60RIB, DKC64-34RIB, and DKC64-87RIB brand blends all handled high pH soil conditions very well; maintaining a dark-green, healthy plant color.
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  • DEKALB® DKC53-68RIB, DKC 56-45RIB, DKC 58-87RIB, and DKC 60-87RIB brand blends all handled high pH soil conditions reasonably well but were slightly paler in color compared to being planted in near-neutral pH soils.
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  • DEKALB® DKC55-20RIB, DKC58-06RIB, and DKC60-67RIB brand blends should be used with caution when planting in high pH soils.
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  • Yields are not shown as the high pH zones in the field had issues with topography, irrigation runoff, and nutrient leaching which makes a true “1 to 1�? yield comparison difficult to achieve.
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What Does This Mean for Your Farm

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  • High pH soils are typically found in areas with eroded top soil and topography changes that make a direct yield comparison of how various seed products perform under high pH soils versus near-neutral pH soil conditions difficult to achieve. Producers may want to keep this in mind when making product comparisons on their farm.
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  • The importance of selecting a corn seed product that can tolerate high pH soils can vary due to the proportion of acres in each field that have high pH soils. For example, a field that is primarily comprised of high pH soils, selection of an IDC tolerant product will be key, whereas in a field comprised of only 1% high pH soils, seed product selection for IDC tolerance is less important.
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  • Corn seed product IDC tolerance by visual color rating is impacted by soil pH but it can also be influenced by other factors such as soil temperature, nutrient availability, and nutrient uptake.  Producers should assess all potential causes when assessing product performance under high pH soil conditions.
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