March 7, 2007 | By: Laura Skillman

Spurred on by higher grain prices, producers are considering bringing fallow land back into production. This can be done successfully if producers follow good management techniques, according to research conducted by the University of Kentucky College of Agriculture.

“We aren’t getting as many questions about this from farmers in western Kentucky as from central Kentucky,” said Lloyd Murdock, UK Extension soils specialist. “There was a lot of land that was eligible to come out of the federal Conservation Reserve Program this year, but all but about 3 million acres have been re-enrolled nationwide.”

In the mid- to late 1990s, UK scientists conducted research in preparation for what was anticipated to be a move from fallowed land to production. It never materialized at that time, but demand and high prices for grain crops are moving producers to consider adding acreage this year. Some of those fields will have been left completely fallow while others may have been used for hay or pasture. 

It is unclear how much fallow land and hay or pasture fields will ultimately switch to row crops, but Murdock said for farmers considering doing so, it is important to understand the challenges.

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. The research conducted earlier by UK can provide producers with answers to some of the challenges they will face in this transition.

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. When determining whether to use some type of tillage system or to no-till, farmers need to consider that tillage will cause the soil structure to deteriorate and organic matter and nitrogen also will decline.

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 No. 1 pest problem in sod ground that is going to be cropped is a rodent called a prairie vole. Voles need food and a full canopy to protect them from predators. Established sod fields provide an ideal environment for large vole populations to exist. Heavy damage from voles can occur in no-till production if they are not controlled.

“Voles are going to be a problem and you’ve got to address that early,” Murdock said. “To address it properly, you need to kill all the vegetation 30 days before you plant.”

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.

“They can really damage a crop, so you are going have to do something to manage voles,” he said. 

While tillage is a very effective way of destroying vole populations, it is not the best option for the soil. If a farmer had the mindset to till for the first year with something like a bog disk to remove the excess vegetation, then returned to no-till the following year, he could retain much of the soil quality, Murdock said.

It is important to plan well in advance and to start control options early to allow for the use of more than one control, evaluate the control achieved, repeat if necessary and change your plans if needed.

The nutrient status of fields that have been in long-term sod change with time, Murdock said. A review of the nutrient status of 50 fields that had been in sod and left fallow for eight to nine years showed high amounts of variability between fields. Each field must be tested and treated separately to assure adequate fertilization and liming for good production. 

“If you’ve got something that’s been out of production for quite some time, it is real important to soil test,” he said. “You can really screw up by not doing that.”

The surveyed fields indicated that phosphorus was low in most fields, which will make it one of the most limiting nutrients in most fields. A significant amount of phosphorus fertilizer will be required for best production.

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.

Because of this available nitrogen, the nitrogen recommended for corn planted using tillage should be reduced by 50 pounds per acre in the first year of production, compared to that recommended in a long-term cropping system. No-till planted corn should only be reduced by 25 pounds per acre or less because decomposition and the resulting available nitrogen will be slower than in tilled fields.

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. However, with the major demand seen for corn and the subsequent high prices, soybeans may not be in the picture for some farmers, he noted.


Lloyd Murdock, 270-365-7541, ext. 207