By TIM THORNBERRY
Kentucky Correspondent

LEXINGTON, Ky. — As planting season approaches, many farmers are looking at the possibility of raising more grain crops due to an upswing in prices and the lure of a bigger market by way of ethanol and biofuels production.

However, bringing a fallow field back to “life” after possibly years or dormancy will take some effort.

It can be done successfully, according to research conducted by the University of Kentucky’s College of Agriculture.

Fallow fields are full of natural life, and in many cases, are plowed but not sown. According to History of Agriculture from Rice University’s School of Science and Technology, “it is believed that the practice of leaving fields fallow originated because some cultures were forced to return to their old fields, and found that the infertile fields they left behind had become more productive.

“This led to the establishment of a rotation system where each growing season certain fields would be left alone or tilled but not planted, extending the useful production life of a set number of fields. Sometimes the fallow fields were used for pasturage for animals, which had the incidental benefit of fertilizing the soil. It was later found that certain plants, thought useless except perhaps for animal fodder, were beneficial to a field’s productivity, and seeds for these plants were planted in fallow fields.”

While it is uncertain just how much fallow land will return to crop fields, UK Extension Soil Specialist Lloyd Murdock said it is important for farmers to understand what they will face.

“If the land has been fallow and in sod for several years, the quality of the soil will be greatly improved,” he said.

Maintaining the quality will require planning and good management. Key factors are fertility and pest control. Research reveals that fields left in grass for multiple years see improvements in pore volume and size distribution, which help with filtration, water-holding capacity, aeration and the portion of soil water available to plants.

Land that has been in sod for 10 years or more will have experienced at least a 1 percent increase in organic matter in the plow layer. Nitrogen is in the organic matter and may be released as the organic matter decomposes. This release is subject to the carbon-to-nitrogen ratio in the residue, tillage method and weather.

Farmers should consider whether soil will deteriorate and organic matter and nitrogen also will decline with tillage; and if so, whether no-till methods are viable for them.

There are advantages to both. While tillage aids in weed control and removes much of the residue from the surface that can harbor pests, no-tillage provides the best option for retaining most of the gains from the field being in long-term sod.

“The nutrient status of fields that have been in long-term sod change with time, Murdock said. “If you’ve got something that’s been out of production for quite some time, it is real important to soil test. You can really screw up by not doing that.”

Dr. Chad Lee, UK Extension grain crop specialist, echoes Murdock’s sentiments as well.

“If the land hasn’t been used for crops for a while, it is important to determine the Ph level in the field, assess the field for weed control and determine if you have any live insects,” said Lee.

Research has shown that a rodent called a prairie vole is the primary pest concern for sod ground that is going to be returned to crops. Those fields provide an ideal environment for large vole populations to exist and extensive damage from the rodent can occur in no-till production if left uncontrolled.

Tillage can be effective in destroying voles, but is not necessarily best for the soil unless a farmer tills for the first year with something like a bog disk to remove the excess vegetation, then returns to no-till the following year. That could retain much of the soil quality.

“Voles are going to be a problem, and you’ve got to address it early,” Murdock said. “To address it properly, you need to kill all the vegetation 30 days before you plant. They can really damage a crop, so you are going have to do something to manage voles.”

Burning the vegetation can also be helpful. Mowing will help some and can help predators see the voles more clearly. Seed treatments are also available to protect seed from voles.

Preparing the fallow field for replanting is obviously important but what to plant could prove to be just as an important decision when returning a field back to crop production. In no-till planting, research showed that soybeans were a better option in the first year a field is returned to production.

So, if it is a toss-up between planting soybeans and planting corn, then soybeans would be the better option, Murdock said.

This farm news was published in the March 21, 2007 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.