Omondi speaking at a field day

Keeping an Open Mind

Emmanuel Omondi head shot Emmanuel Omondi

University of Wyoming

SARE grant: Potential of Managing Iron and Zinc Deficiency in Dry Beans with Interplantings of Annual Ryegrass and Increased Bean Density (2008)

Where he is now: Research Director, Rodale Institute's Farming Systems Trial

Dry beans, Wyoming’s fourth-largest crop by value, can suffer reduced yield and quality due to deficiencies of the micronutrients iron and zinc. This is a normal occurrence in soils with low organic matter and a high pH, which are common in Wyoming. The most conventional solution is to add micronutrients through repeated chemical sprays, but a potentially cheaper alternative explored by a SARE-funded graduate student and some inquisitive farmers lies in something much simpler: grass.

University of Wyoming graduate student Emmanuel Omondi first observed the positive effect of ryegrass on dry beans on the farm of Mike and Cindy Ridenour. Funded by a 2008 SARE Graduate Student grant, Omondi sought to explain the effect by focusing on pH, organic matter and other soil characteristics. Looking back, he notes that this specific premise “kept his mind in a box” and limited results. However, after he finished his master’s degree and started working on his Ph.D., he had a flash of insight that opened his mind to other possibilities.

This “flash” led Omondi to consider the contribution of other soil nutrients toward iron deficiency. Further research showed that surplus nitrogen, and manganese to a degree, were responsible for the deficiency. Ryegrass reduced the concentration of these nutrients in the soil and thus alleviated the iron deficiency that reduces yields. While more research is needed to make intercropping ryegrass viable commercially, it can potentially save farmers money by reducing the need to spray micronutrients such as iron sulfate. In 2008, Omondi noted that farmers forced to spray iron sulfate two to three times per season would spend $10 to $35 per acre, money that would be saved if ryegrass could do the job just as well.

Omondi's research originated through his involvement with Mike and Cindy Ridenour's 2006 Farmer/Rancher grant project to test the benefit of intercropping ryegrass on their farm. “The results of the experiment were encouraging and clearly indicated that there existed some form of symbiosis between the grass and the beans,” Mike Ridenour says.

As a University of Wyoming graduate student, Omondi was brought on to the Ridenour’s field experiment as a research assistant. When he saw the remarkable results of the Ridenour's project, he jumped on the opportunity to further the research by studying how intercropping annual ryegrass with dry beans alleviated micronutrient deficiency chlorosis and produced better yields compared to growing beans alone.

“Cindy and I are pleased to have been a part of Dr. Omondi’s master’s and doctoral work,” Mike Ridenour says. “Through the grants from Western SARE, Emmanuel was enabled to take his enthusiasm and curiosity to expand our scientific understanding of plant-soil interactions, and to become a learned professional within the global agricultural research community.”


See Omondi's scholarly publications at


Omondi reached more than 400 farmers and researchers by presenting his work at the University of Wyoming Sustainable Agriculture Research and Extension Center's annual field day for four years.

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