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

Project Overview

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

Annual Reports


  • Agronomic: hay, medics/alfalfa, oats


  • Crop Production: cover crops, cropping systems, crop rotation, intercropping
  • Education and Training: on-farm/ranch research, participatory research
  • Production Systems: organic agriculture


    Small grains, such as oat (Avena sativa L.), are an important component of organic row crop operations in the Upper Midwest. Beyond providing goods for either on-farm use or sale, like grain and straw, they help disrupt above and below ground pest and disease life cycles, provide opportunities for establishing legumes for either forage or green manure purposes, and promote more even distribution of farm labor over the cropping season. Unfortunately, aside from these functions, the economic value of small grains themselves is usually less than other crops within the rotation, primarily corn (Zea mays L.) and soybean (Glycine max (L.) Merr.). As a result, oats are often the financial weak link in diversified crop rotations. This is due to a combination of price, yield, and grain quality (test weight), which is often insufficient (<36 lbs. /bushel) for the food-grade market. Consequently, oats receive little agronomic attention either from farmers or researchers. Both limited institutional support and a loss of generational knowledge about small grains production has limited the amount of information available to aid farmer decision-making. Given this, our goal was to examine the potential for improving oat grain yield and quality through simple low or no-cost agronomic practices.

    Experiments took the form of both on-station and on-farm research. On-station research was conducted over two seasons (2015 and 2016) on the Iowa State University (ISU) Marsden research farm in Boone, Iowa. This experiment examined the effects of seeding date and oat crop density on grain yield and test weight, in addition to end of season alfalfa and weed biomass and net returns. 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: 1.) What is the effect of oat crop density? 2.) What is the effect of rotary hoeing? 3.) What is the effect of sowing oats with and without an underseeding? Results from our experiments helped to highlight and quantify areas of potential improvement in oat crop management, while also clarifying limitations to agronomic practices.

    On-station research demonstrated the importance of seeding as early as possible. Not only were yield, test weight and net returns maximized by early planting, but alfalfa biomass was greater and weed biomass lesser in one of the two years, indicating that early planting may actually improve objectives other than grain yield and test weight. On-farm research similarly showed that 1.) oat crop density had no effect on grain yield, test weight, forage legume biomass, or weed biomass. However, that equivalent yields were attained across the tested oat crop densities suggests that net returns could be optimized at lower oat crop densities and associated seeding rates 2.) Weed biomass was reduced as a function of rotary hoeing at one of the two farms that participated in this specific trial. However, this tactic had no effect on oat grain yield or test weight and 3.) yield of oat sown without an underseeding was greater than oat with an underseeding at one farm, but test weight between the treatments did not differ. Neither yield and test weight differed at the other participating farm. There was also no difference in weed biomass between oats planted with and without an underseeding at either farm. 

    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 the varied results we found and its lack of positive impact on grain yield and/or test weight. Lastly, the use of an underseeding does not seem to substantially alter outcomes important to an oat production year (yield, test weight, weed biomass). While results were mixed, farmers who participated in the trials were enthusiastic and positive about learning more about their growing practices and about contributing useful information.   

    Project objectives:

    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. In addition to on-station research at an ISU research farm, we planned on and undertook a substantial participatory component to the research. One important objective was to make our results freely accessible  through a variety of media and other platforms including field days. Furthermore, we made sure to link our efforts from the outset directly with those of local non-profit organizations with large constituencies that would be interested in this area of research.

    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.