Agricultural Soil Compaction: Causes and Management

Compaction of soil is the compression of soil particles into a smaller volume, which reduces the size of pore space available for air and water. Soil compaction can be a serious and unnecessary form of soil degradation that can result in increased soil erosion and decreased crop production. This fact sheet discusses the importance of soil porosity, looks at several different types of soil compaction that may occur, and outlines best management practices to prevent soil compaction.

Fertilizing Eroded Knolls

Many farmers have fields dotted with eroded knolls that are relatively unproductive. This fact sheet takes a quick look at the best ways to restore the productivity of these knolls.

Management of Solonetzic Soils

Solonetzic soils, often called burnout or gumbo soils, are characterized by a tough, impermeable hardpan that may vary from 5 to 30 cm (2 to 12 in.) or more below the surface. This hardpan severely restricts root and water penetration of the subsoil. Variation in the hardpan causes crops to have a wavy growth pattern during periods of moisture stress. Deep plowing and, more recently, subsoiling have been developed as methods for improving some of these soils. More than 160 deep tillage trials have been established to identify the Solonetzic soils with the greatest potential for improvement and to determine crop responses. This fact sheet presents the results obtained from these trials.

Soil Organic Matter

The cultivation of prairie soils has generally resulted in a decline in organic matter of 30 to 50 per cent. A product of this decline has been the release of large amounts of plant nutrients, particularly nitrogen. Crop rotations with a high frequency of summerfallow have relied on the nitrogen released from soil organic matter to supply crop requirements. More frequent or continuous cropping, less frequent tillage, the production of high yields and the return of crop residues will help to maintain soil organic matter at a satisfactory level. Perennial forages are effective for maintaining or increasing soil organic matter.