Cover Crop Effects on Iron Chlorosis in Soybeans on High pH Soils


  • Evaluate the effects of cover crop and poultry litter on growth and yield of Pioneer® brand soybean varieties on high pH soils in the Blackbelt Region of Alabama.

Study Description

University Cooperator:      Dr. Dennis Delaney,
Auburn University
Soil pH:    8.1
Experimental Design:    Randomized Complete Block
Replicates:    4
Cover Crop:    None/Fallow
Wheat Cover Crop
Poultry Litter:    None
2 tons/acre
Pioneer® Brand
Soybean Varieties:
   95Y40 (R) -- 3*
95M82 (R) -- 4*
95Y70 (R, STS) -- 4*
96M60 (R) -- 7*

*Iron Chlorosis score rated on a scale of 1-9 where 1=susceptible and 9=tolerant.

Soybean variety susceptible to iron chlorosis (95Y40) with no cover crop.
Soybean variety susceptible to iron chlorosis (95Y40) with cover crop of poultry litter application.

Soybean variety susceptible to IDC (95Y40), with poultry litter application. Montgomery County; May 15, 2012.


  • Using a cover crop increased yields of all soybean varieties.
  • Yield of the most iron deficiency chlorosis (IDC) sensitive variety (95Y40) was increased 45 bu/acre when a cover crop was utilized.
  • Yield increases associated with a cover crop ranged from 20 to 31 bu/acre with other varieties.
  • Yield of all varieties was similar when a cover crop was utilized.
  • Using a cover crop increased yields in the presence and absence of poultry litter.
  • Maximum yields were achieved when a cover crop was used in combination with poultry litter.
  • These findings suggest that a wheat cover crop can reduce the severity of iron chlorosis on high pH soils and provide a means of effectively using poultry litter as a nutrient source.
Cover Crop Effect on Soybean Yield.
Cover Crops and Poultry Litter Effects on Soybean Yield.

2012 data are based on average of all comparisons made in one location through March 19, 2013. Multi-year and multi-location is a better predictor of future performance. Do not use these or any other data from a limited number of trials as a significant factor in product selection. Product responses are variable and subject to a variety of environmental, disease, and pest pressures. Individual results may vary.


Always follow grain marketing, stewardship practices and pesticide label directions. Varieties with the Glyphosate tolerant trait (including those designated by the letter “R” in the product number) contain genes that confer tolerance to glyphosate herbicides. Glyphosate herbicides will kill crops that are not tolerant to glyphosate.
Varieties with the DuPont™ STS® gene (STS) are tolerant to certain SU (sulfonylurea) herbicides. This technology allows post-emergent applications of DuPont™ Synchrony® XP and DuPont™ Classic® herbicides without crop injury or stress (see herbicide product labels).
NOTE: A soybean variety with a herbicide tolerant trait does not confer tolerance to all herbicides. Spraying herbicides not labeled for a specific soybean variety will result in severe plant injury or plant death. Always read and follow herbicide label directions and precautions for use.
DuPont™, STS®, Synchrony® XP and Classic® are trademarks or registered trademarks of DuPont or its affiliates.

PIONEER® brand products are provided subject to the terms and conditions of purchase which are part of the labeling and purchase documents.