Optimizing Organic Oat (Avena sativa) Production and Profitability in Iowa

2016 Annual Report for GNC15-216

Project Type: Graduate Student
Funds awarded in 2015: $9,985.00
Projected End Date: 06/30/2017
Grant Recipient: Iowa State University
Region: North Central
State: Iowa
Graduate Student:
Faculty Advisor:
Dr. Mary Wiedenhoeft
Iowa State Univ

Optimizing Organic Oat (Avena sativa) Production and Profitability in Iowa


In the spring of 2015 and 2016, we conducted research on organic oat production. Oats play an important role within extended rotations in the Upper Midwest. In addition to providing grain, they aid in disrupting pest cycles and in establishing forage legumes. Our goal was to investigate the effects of different management tactics on variables that are economically vital within a single season (oat grain yield and test weight) and those that contribute the proper functioning of the system (alfalfa and weed biomass). Experiments took the form of both small plot and on-farm research. Small plot research was conducted over two seasons on the same Iowa State University research farm. The small plot experiment examined the effects of seeding date and oat density on the variables mentioned above. On-farm trials were established on seven farms across the state over the same two year period. These trials were used to explore the following research questions with respect to oat yield, test weight, forage legume biomass and weed biomass: What is the effect of oat crop density? What is the effect of rotary hoeing? What is the effect of sowing oats with and without and underseeding?

Objectives/Performance Targets

Our goal with this research was to generate much needed data about the effects of basic low-cost crop management tactics related to an oat rotation year. Our hypotheses were intended to address farmer concerns around no or low-cost management practices that could be implemented to improve the production and profitability of oats and the associated services of a small grain rotation year. We planned on having a substantial participatory component to the research and to make all findings freely accessible. Furthermore, we made sure to link our efforts directly with those of local non-profit organizations with large constituencies that would be interested in this area of research.


Over the two years of the experiment, both yield and test weight were greater at earlier seeding dates. Oat density did have an effect on grain yield. Yields plateaued around 20 plants per square foot. Oat density had no effect on test weight. Alfalfa biomass did not differ as a result of oat density but had greater biomass at earlier sowing dates. Weed biomass did not differ as a result of either oat density or sowing date. Similarly, results from on-farm trials indicated that density did not have an effect on yield. Density also had no effect on either forage legume or weed biomass. In another on-farm trial, testing the effect of rotary hoeing, there was less weed biomass in rotary hoed plots. However, this tactic had no effect on oat grain yield or test weight. Yields and test weight also did not differ in the last on-farm trial, which compared the performance of oats with and without an underseeding. There was also no difference in weed biomass between oats with and without an underseeding. The results generated from the small plot research highlight the importance of seeding oats as early as is feasible. Cumulatively, data from both small plot and on-farm research suggest that economical optimal yields can occur at relatively lower densities without negatively affecting alfalfa establishment or weed suppression. Mechanical cultivation with a rotary hoe may not be a tactic of interest for farmers considering its lack of impact on grain yield and test weight. Lastly, using an underseeding does not seem affect oat yield or test weight.

Impacts and Contributions/Outcomes

We have been fortunate to share results, ideas and farmer feedback about these experiments with a large group of individuals. Over the last two years, a combination of focus group meetings, conference presentations and field days have been given to over 250 farmers and associated agricultural professional in the seed and milling industries. Our research has been featured in popular press such as Wallace’s Farmer and numerous web based articles via Practical Farmers of Iowa. Additionally, many of the farmers directly involved with the on-farm trials and M.S. student David Weisberger, have participated in a video series on small grains production entitled “Rotationally Raised”, which is freely available on: https://www.youtube.com/user/pfivideos. Additionally, reports that detail individual on-farm trial and its results will soon be available on the Iowa Organic Association website: http://www.iowaorganic.org/. wallacesfarmer.oct_.16


Dr. Matt Liebman

1401 Agronomy Hall
Ames, IA 50011
Office Phone: 5152947486
Dr. Margaret Smith

Extension Program Specialist
2203 Agronomy Hall
Ames, IA 50011
Office Phone: 6414309241
Dr. Mary Wiedenhoeft

Iowa State University
1126 Agronomy Hall
Ames, IA 50011
Office Phone: 5152943274