Compaction happens. Machinery traffic, tillage, raindrop impact and field operations on wet soil all contribute to soil compaction.

Signs of compaction include poor soil drainage due to low infiltration, standing water and excessive runoff because of reduced porosity, says Jay Jabro, a research soil scientist at the USDA-ARS Northern Plains Agricultural Research Laboratory in Sidney, MT.

Compacted soil is cloddy, hard to work and prone to surface crusting and cracking. Crops growing in compacted soil show shallow or abnormal roots, uneven stands and reduced yields.

But when it comes to the remedy, “You don’t always need steel,” says Hal Weiser, a soil specialist with the North Dakota Natural Resources Conservation Service. “There are other options for dealing with compaction.”

Perennials and annual plants with strong taproots are very effective at alleviating compaction, he says. A cash crop like sunflower has “a deep, aggressive taproot” that can break through tillage pans.

Forage radish, a cool-season cover crop, is also very effective at breaking through compaction layers. Planted in late summer, after winter wheat, spring wheat or early corn-silage harvest, tillage radish will keep growing as long as nighttime temperatures are above 18° F, he says. Even in North Dakota, with its short growing season, radishes seeded in early August can reach 1-2 in. in diameter and 10-14 in. long, he adds.

Some livestock producers are interseeding forage radish into corn at V-6 for fall grazing after harvest. By spring, Weiser says, “The residue is gone. All that remains is the skeleton.” Corn planted the next spring “just follows the radish right down.”

The very best crop for breaking through compaction layers is alfalfa, with its deep taproot system, Weiser says. He suggests growers try out “bio-tillage” on small problem areas, like compacted headlands or low spots within fields, which are often worked wet.