ALTERNATIVE CROPPING MAY DOUBLE HARVEST

The system can afford a number of production and environmental benefits

An alternative production system being adopted by Ohio growers might be cause for a double-take of wheat fields in the spring.

During the time when wheat is maturing, tiny soybean plants are popping up in neat rows alongside their neighbor. The system, known as Modified Relay Intercropping (MRI), is the practice of interseeding soybeans into wheat so that two crops are growing in the same field during the crop season.
The idea of such a system has intrigued many Ohio growers. Farmers in such counties as VanWert, Hancock, Seneca and Huron have adopted the practice. In fact, growers in Crawford County have been so successful that one-fifth of the county's 20,000 wheat acres are now under the alternative cropping system.

Steve Prochaska, an Ohio State University Extension agent with Crawford County who has led research on the system for nearly 15 years, said that if done properly, the system could afford a number of production and environmental benefits.

"The system may better utilize sunlight energy and soil moisture so that a grower can produce two crops in one year from the same field," said Prochaska. "Because of this, growers may be able to reduce their fixed assets and potentially increase their profitability."

The idea of Modified Relay Intercropping involves planting wheat in slightly wider row spacings . anywhere from 10 inches to 15 inches apart. Traditional wheat row spacings are 7 inches to 8 inches wide. Soybeans are then sown into the field about three to four weeks prior to wheat harvest in row spacings that match the wheat. The wheat, when harvested, is cut just above height of the soybean plants in the field.

Research has shown that over time soybeans in the MRI system have yielded about 50 percent to 60 percent of Crawford County's average (28 bushels/acre). MRI wheat yields can be expected to be about 85 percent to 90 percent of conventional wheat yields.

Despite the overall success of the system, Prochaska said significant management is required to make it work.

"The timing of interseeding the soybeans is critical. Planting too early or too late may result in the plants dying or soybean yield decrease," said Prochaska. "Also growers must have a tram line established before they even begin to plant wheat. If they don't, then they will not be able to drive through wheat without seriously damaging it."

Such production management is beneficial both to the grower and to the environment. The tram line, for example, is a form of controlled traffic . a method whereby all farm equipment is the same width so that traffic is confined to specific paths, and the remainder of the soil is untouched. The method, combined with 100 percent plant cover, mitigates soil compaction, reduces soil erosion and improves overall soil quality, thereby potentially increasing crop performance.

One disadvantage with Modified Relay Intercropping is the need for adequate soil moisture June through August for the soybean crop to yield well.

"Soybeans need about 8 inches of rain in the June through August period combined with residual soil moisture during this time period," said Prochaska. "Since wheat tends to use up the soil moisture reserved for soybeans early in the season, a year with inadequate rainfall or a drought will substantially hurt the soybean crop." In fact, Ohio State research has shown that in years where this is the case, soybean yields have been very low. Because of the drought situation in 1999, for example, soybean yields under the alternative system averaged only five bushels per acre.

Ohio State researchers continue to analyze the system under a variety of production situations.

"Modified Relay Intercropping is a good system and it works," said Prochaska. "The business of farming is to make money and protect the environment and that is what we aim to do with alternative cropping systems such as MRI."