Project Details:

Interpreting the contribution of cover crops to soil health and crop productivity

Parent Project: This is the first year of this project.
Checkoff Organization:Iowa Soybean Association
Categories:Crop management systems
Organization Project Code:
Project Year:2015
Lead Principal Investigator:Alison Robertson (Iowa State University)
Co-Principal Investigators:
Larry J Halverson ((not specified))
Gwyn Beattie (Iowa State University)
Leonor Leandro (Iowa State University)
Keywords: Cover Crops, On-Farm Research, Root Health, Soil Microbiology

Contributing Organizations

Funding Institutions

Information and Results

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Project Summary

The value of cover crops for sustaining and improving soil and water quality, and thereby contributing to agriculture productivity, is becoming more widely recognized. Not surprisingly, many soybean producers have become interested in including cover crops in their farming operations. Benefits associated with cover crops include reduced erosion and nutrient losses, improved soil structure, water infiltration, and water-holding capacity due to greater organic matter content, and weed suppression.

The extent to which cover crops benefit crop yields may vary with soil and climatic factors, as their decomposition can release or immobilize nitrogen. An improved understanding of these factors and their effect on yield response is needed. Therefore, the long-term goal of this research project is to elucidate the effects of cover crops on soil health and the root rnicrobiome to better exploit the benefits of cover crops and predict their impact on soybean yield.

This proposal is novel in that we plan to conduct our research on commercial soybean fields in collaboration with the On-Farm Network and characterize the community structure of the root microbiome and disease incidence in their cover crop strip trials.

Project Objectives

1. To evaluate the impact of cover crops on the root rnicrobiome in cover crop strip trials established by the On-Farm Network.
2. To evaluate the impact of cover crops on stand establishment, prevalence of diseases and root health in cover crop strip trials established by the On-Farm Network.

Project Deliverables

Our proposed research will positively impact Iowa and Midwest soybean growers by advancing knowledge on the effect of cover crops on soybean and corn yield, specifically, how improved soil and plant health increase productivity.

Data will be shared with ISA and growers through ISU Extension and On-Farm Network events, Integrated Crop Management News (, project progress reports, and ISA Communications.

Progress of Work

Three fields (two in northwest and one in southwest Iowa) identified by the On-Farm Network (OFN) were sowed with cover crop strips in Fall 2014.

We have developed experimental protocols for capturing microbial community information, including: (i) effective extraction methods for obtaining high quality DNA from bulk soil, root surfaces, and root tissues of corn and soybean samples, (ii) methods for consistent high-fidelity amplification of microbial bio-markers, and (iii) protocols for high-throughput sequencing. We have developed computational pipelines for analyzing and comparing the composition of microbial communities.

We verified the quality of these pipelines using an artificial community composed of 20 microbial species as a reference dataset and communities from soybean samples from other studies as test datasets. Our pipelines were able to identify community members at the genus level, quantify the relative abundance for each genus, and identify microbial groups that differed significantly in abundance among the communities. Many of the bacteria and fungi identified in our soybean root datasets were identified as root colonists and root endophytes in published studies, providing validation of our approaches. We are now in a strong position to apply these protocols and pipelines to samples collected in our investigation into the impact of crop rotation on soil and root microbiomes.

The PIs and OFN met with Dr. Sotirious Archontoulis in March 2015 to discuss how data collected in this project, specifically quantitative data related to the microbiome, might contribute to the APSIM model that work Dr. Archontoulis is working with.

Final Project Results

See attached final report

View uploaded report Word file

Benefit to Soybean Farmers

Performance Metrics

Project Years