MDA - Cover crops

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Cover crops are grasses, legumes or forbs planted to provide seasonal soil cover on cropland when the soil would otherwise be bare—i.e., before the crop emerges in spring or after fall harvest.

Common cover crops in Minnesota include rye and other small grains, buckwheat and hairy vetch. Cover crops are best suited to areas of the state with plenty of water available in the soil for both the cover crop and the main crop.

Using cover crops in Minnesota can be difficult because of the small window of opportunity to establish them. Minnesota farmers have nonetheless found creative ways to utilize cover crops, such as:

  • After harvesting corn silage in the first week of September
  • After harvesting vegetable crops like peas and sweet corn
  • Over-seeding into a standing crop like soybeans
  • In organic systems with diverse crop rotations

The fact sheet Are You Covered? provides more information about windows of opportunity for cover cropping in Minnesota.

Cover crops have many different uses and names, depending on the main purpose being served:

  • A winter cover crop is planted in late summer or fall to provide soil cover over winter. In Minnesota, winter cover crops are commonly planted after potato harvest primarily to reduce wind erosion.
  • A catch crop is a cover crop planted after harvesting the main crop, primarily to reduce nutrient leaching. Many southeastern Minnesota growers use cover crops in this way and are cooperating with the Minnesota Department of Agriculture on related research and demonstration projects.
  • A smother crop is a cover crop planted primarily to outcompete weeds. In Minnesota, buckwheat and rye cover crops commonly serve this purpose.
  • A green manure is a cover crop incorporated into the soil while still green, to improve soil fertility. Currently in Minnesota, green manures are used primarily by organic growers.
  • Cover crops can serve as short-rotation forage crops when used for grazing or harvested as immature forage (green chop).

Living mulches are similar to cover crops. Living mulches are interplanted with a cash or commodity crop but stay alive throughout production of the main crop. They are typically used with specialty crops, including orchard and nursery crops.

Why plant cover crops on your land?

Environmental benefits

  • Reduces wind and water erosion when the soil would otherwise be bare - in early spring prior to planting, in fall after harvest, over winter or between vegetable crops
  • Improves water and soil quality by adding soil organic matter; this creates an open soil structure that allows water in more easily, reducing runoff
  • Protects groundwater quality by preventing nitrogen from leaching into the water table

Practical benefits

  • Provides supplemental forage for grazing livestock
  • Stores significant nitrogen for use by the next crop and enhances overall soil fertility
  • Suppresses weeds by shading the soil and using moisture that would otherwise be available for weeds; deep-rooting cover crops also loosen and aerate compacted soil
  • Helps soil retain moisture for use by primary crops; cover crops on the soil surface reduce evaporation
  • Attracts beneficial insects
  • Enhances traction for harvest in wet soils

Similar & related practices

Cover crops can be incorporated into manure management, nutrient management and pest management & especially weed control.

Organic growers typically use cover crops in rotation with other crops as part of a conservation crop rotation system. The cover crops are also an essential source of nitrogen for organic growers.

Riparian buffers such as grass filter strips and forested buffers are important complementary practices for water quality purposes. Whereas cover crops help minimize soil erosion and runoff from fields, buffers adjacent to waterways provide a second defense against water pollution by trapping and filtering any sediments and other potential pollutants that do leave the field.

Other similar or related erosion and runoff control practices covered in this Conservation Funding Guide include conservation tillage, rotational grazing and grass planting.

More information

Guidance from USDA's Natural Resources Conservation Service (NRCS)

Other resources