There’s more than corn and soybeans in Iowa — Who knew?!

By Christina Riessen

Take a drive around Iowa State University research farms this summer and you’ll find some research plots growing something more exotic than corn or soybeans.

• California blackeye cowpeas (normally grown in the west)
• Purple hull pinkeye cowpeas (commonly seen in the south)
• Lablab Rongai (also known as hyacinth bean and grown in Africa and Asia for grain, forage and as a leafy vegetable)
• Canola, wheat and turnips (produced in the north)

Purple hull pinkeye cowpeas 

Each of these crops may provide Iowa farmers with additional options to diversify the Iowa landscape while providing quality yields and profits.

Rosemary Bulyaba, an agronomy graduate student, is researching leaf production in soybeans, cowpeas and hyacinth bean this summer. She is studying the nutritional quality of leaves for human and livestock consumption, and how harvesting up to 75 percent of the leaves from the top of the plant affect grain yield and nutrients.

The study also involves analyzing the chemical composition of the leaves, which contain one of the highest percentage of protein of any crop plant, making it valuable in human diets in Africa. Hyacinth bean is a good source of crude protein and fiber and is among the most palatable legumes for animals.

Bulyaba, who works with agronomy associate professor Andy Lenssen, also analyzes the effects of different treatments to cowpeas, soybean and hyacinth bean on nutrient content, yield and nitrogen fixation into the soil. Nitrogen-fixing bacteria found in legume roots and/or a fungicide seed treatment are applied to each crop.

Several ISU research projects focus on canola, a member of the mustard family that has bright yellow flowers.

After corn was chopped for silage at the ISU Dairy Farm last year, Tim Sklenar, an agronomy graduate student also studying with Lenssen, planted winter crops of cereal rye, canola, purple top turnips and false flax for cover crop and double-crop studies. The project compares the effects on yield of different management systems used to grow canola in various Iowa climatic factors.

Michelle Cryder testing for light infiltration.

Another canola research program looks at the oil content of a number of varieties of mustard species. Twelve varieties of canola, along with false flax, are being analyzed by Jerry Hatfield and research technician Michelle Cryder from the USDA-ARS National Laboratory for Agriculture and the Environment. False flax and canola contain 30 to 40 percent oil, some of the highest of any seed, giving them a promising future in biofuel production.

Canola also is the focus of two projects conducted by graduate students of Mary Wiedenhoeft, agronomy.

Rafael Martinez-Feria is investigating cool-season cover crops, including winter canola, to determine planting dates for different biomass yields and whether it increases corn yield after soybeans. Canola is a crop that needs fewer inputs, he said, adding that nitrogen fertilizer requirements for canola are half to a third those of corn.

Stefans Gailans is examining whether spring and winter wheat and canola can extend the crop rotation cycle. An extended crop rotation cycle such as corn, soybeans and a winter annual will disrupt pest (weed, disease and insect) life cycles, reducing the chance for resistance and pest populations.

The general objectives of each of these studies are to lengthen crop rotations (three years of three different crops), to provide an alternative crop to consider in rotations and to provide a cover crop throughout the season. Having a cover crop such as canola improves the agronomics, economics and the agroecosystem of a field.