Interactive Effects of Cover Crops, Soil Health Practices, and Insect Community Dynamics on Corn Production

Project Overview

Project Type: Graduate Student
Funds awarded in 2016: $9,998.00
Projected End Date: 05/10/2017
Grant Recipient: South Dakota State University
Region: North Central
State: South Dakota
Graduate Student:
Faculty Advisor:
Jonathan Lundgren
South Dakota State University


  • Agronomic: corn


  • Crop Production: cover crops
  • Farm Business Management: budgets/cost and returns
  • Natural Resources/Environment: biodiversity
  • Pest Management: integrated pest management
  • Soil Management: organic matter

    Proposal abstract:

    Today, many agricultural landscapes aim to maximize the amount of harvestable land, which has resulted in a reduction of agroecosystem biodiversity. This study investigates the relationships that exist among cover crop diversity, insecticide use, and soil conservation practices, soil health, and insect communities in a corn production system. The objective of the study is to implement vegetation diversity and soil management to increase insect biodiversity, as well as to explore the relationship between insect communities, plant diversity, and soil health. The hypothesis addressed in this study was that insecticide use and cover crop utilization affect pest abundance and predator: prey ratios in corn fields, and that profitability of the corn production system differs between treatment types. The role of cover crops in reducing insect pests of corn, increasing natural enemies of pests, and encouraging insect contributions to soil health were investigated in ten paired treatments conducted across four states (NE, SD, MN, ND). Insect diversity and soil properties will be assessed in plots that have one of the following treatments: no cover crop established with conventional pest management practices such as genetically modified (GM) corn and other insecticidal usage (bare soil), and a treatment in which a cover crop was established prior to corn, with non-GM corn and no insecticidal treatments, with a legacy of soil cover (cover crop). The study directly compares the cost of conventional pest management practices with the use of cover crops and no-till practices to control pests. Data were collected within systems that were defined and created by the producers, to emulate a realistic crop producing scenario to examine this systems-level question. Soil qualities are assessed by taking soil cores for analyzing Soil Organic Matter (SOM), testing water infiltration rate, and determining soil bulk density. Insect communities in each field were assessed by taking soil cores, quadrat suction sampling, and by counting all insects on whole corn plants. Preliminary results reveal that there is no significant difference in pest abundance between treatments, except for aphids, which are less abundant in the cover crop treatment. There is also no significant difference in corn yield between treatments, while overall profitability remains to be calculated. These data and the rest of what is found will be disseminated to the participating producers and their communities to guide their decision making while managing for pests.

    Project objectives from proposal:

    Learning outcomes. The farmer participants (20) are volunteers whom are eager to see the results of the research. These farmers want to know if conventional pest management is cost effective and necessary for producing healthy corn. Along with participating farmers, results will reach rural communities throughout the Midwest through a variety of venues. Participants will learn the consequences of their management practices and better understand sustainable agriculture systems. Farmers will learn that biodiversity provides quantifiable and valuable services. Knowledge of this principle is key to adapting practices to achieve profitable, sustainable farming.

    Action outcomes. Based on preliminary data, corn fields relying on winter vegetation (cover crops) had 10-fold fewer aphids than corn fields managed with Bt varieties and insecticides (F1,50 = 6.06, P = 0.02) Appendix 1: Figure 1 Perhaps more importantly,  no European corn borers were found in cover cropped systems; larvae were found only in conventionally managed systems. All other pest abundances were unaffected by treatment.

    Additionally, our preliminary data did not reveal significant differences in yield between treatments Appendix 1: Figure 2. Action outcomes of this study include reducing the amount of insecticides applied to pest management, increasing biodiversity in corn agroecosystems and reducing the toxins released into the environment. Controlling pests proactively and with a systems-level approach will improve economic well-being for corn producers, and this profitability will be calculated with the help of an economist. Results will increase farmer and institutional inquiry into issues of long-term agricultural sustainability, and re-thinking current agricultural paradigms.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.