If you’ve ever considered adding pulse crops to your crop rotation, you may want to give this option a closer look. Not only do pulse crops improve the quality of the soil and reduce the need for herbicides and fungicides, they also break up the cycle of insects, weeds and crop diseases. Research shows that pulse crops may increase the yield of subsequent crops and produce a better-quality crop.

Pulse crops are defined as legumes with dry seeds that are edible for humans. The most common pulse crops are field peas; beans, such as navy, pinto and kidney; lentils; and chickpeas. Though soybeans are technically a pulse crop, in the U.S. they are classified as an oilseed. Pulses may be used for livestock and human consumption.

One in a million. Legumes are unique because they convert nitrogen gas found in the atmosphere for their own use, making the application of additional nitrogen unnecessary. Once they’re harvested, the remains break down and release nitrogen into the soil, which is usable by the next crop. In fact, nitrogen benefits may last for two or three years. With nitrogen prices at sky-high rates, planting pulse crops can be especially appealing to corn growers, for whom nitrogen is one of the biggest expenses.

However, planting pulse crops must be done in moderation, says Dwayne Beck, manager of Dakota Lakes Research Farm and plant science professor at South Dakota State University. “Broadleaf crops—pulse crops and things like sunflower and soybeans—are low in residue compared to grass crops, such as wheat and corn. If we seed low-residue crops too frequently, there is not enough residue to keep the soil covered, prevent erosion and conserve moisture.

“These crops also share some common diseases unique to each species. Seeding them every year would lead to problems with weeds, diseases and insects,” Beck says. Switching species may help prevent diseases, but it will depend on individual circumstances.

For instance, because chickpea needs a longer break between plantings, it can be used every six years with another pulse or oilseed added to the rotation. “A simple example would be wheat–corn–chickpea–wheat–corn–
chickpea,” Beck says.

Because they are cool-season plants, peas, lentils and chickpeas are best suited for Northern climate and soils. Dry peas and lentils were primarily grown in the Pacific Northwest until recently; North Dakota and Montana are now the leading pea and lentil producers, and California is one of the highest chickpea growers. Beans are a warm-season crop, with North Dakota and Michigan as the largest producers. Other commercial bean-growing states include California, Arizona, New Mexico, Texas, Colorado, Kansas, New York and Utah.

The biggest competitor is Canada, the world’s leading pea and lentil exporter and one of the top five bean exporters. In 2006, Canada’s pulse exports were valued at more than $1 billion, says industry association Pulse Canada, with an average of 4 million to 4.5 million tons produced annually.

There are many markets for pulse crops—the most profitable is the human consumption market. But this market is risky, Beck says. “If you grow green peas for human consumption, then have them bleached, they’re still suited for feed with some loss of value.” Lentils, chickpeas and beans can also be used for feed if they don’t make the grade, but the loss of value will be significant since they don’t produce as large volume of seed as peas.

Using peas for feed has advantages. Due to their high protein content, peas can be mixed with lower protein feeds or used alone. Peas have an energy component similar to corn. The feed pea market is large, with Europe as the No. 1 importer. There is also a huge feed industry in China, making it a potential market for pea producers. A North Dakota State University study says beef that has been pea-fed may have increased juiciness and tenderness with no difference in flavor.