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Abstract
Dry beans (Phaseolus sp) are grown extensively throughout the western Great Plains. The high pH soils prevalent in this region limit the availability of many micronutrients, especially iron and zinc. Iron deficiency in high pH soils results in interveinal chlorosis in beans and a higher susceptibility to insect and disease damage, thereby reducing yield and quality. In 2002, Mike and Cindy Ridenour of Meadow Maid Foods in Goshen County, Wyoming observed that pinto beans (Phaseolus vulgaris L.) intercropped with annual ryegrass (Lolium multiflorum L.) did not exhibit iron-deficiency chlorosis and produced better yield than beans grown without the ryegrass intercrop. Field studies were conducted on the Ridenour's farm in the summer of 2006 to test the hypothesis that an annual rye intercrop would result in increased iron concentration in pinto beans. Treatments included beans planted in annual ryegrass residue incorporated in the soil, bean-annual ryegrass intercrop, and beans planted alone as a control. The bean-annual ryegrass intercrop resulted in significantly higher soil iron and zinc concentration compared to beans planted alone. There were no significant differences between treatments for tissue iron and zinc concentration. There were also no significant differences between treatments when the experiment was repeated in the UW Plant Sciences greenhouse in the summer of 2007 to validate these findings in a controlled environment.
