By Christina Riessen,
Following crops are growing 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)
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.
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.
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.