Madison County Soil Conservation District 

Serving to Conserve Madison County's Soil & Related Natural Resources Since 1941


Home Up Outreach Programs Our Soil Our Water Plants & Animals Site Map Helpful Links

Cover Crops


 

 

  DEFINITION

  Cover crops are grasses and legumes are grown in crop fields between harvest
  and planting to protect the soil from washing.

  Benefits:

        Reduce erosion.

        Increase soil organic matter.

        Manage excess nutrients in the soil profile.

        Promote biological nitrogen fixation.

        Increase biodiversity.

        Weed suppression.

        Provide supplemental forage.

        Soil moisture management.

 

 

  Characteristics of Different Species
  Small Grains, Cool Season

Rye - Cereal rye is the most drought resistant and cold tolerant cool season annual grass.  It has an extensive root system and makes rapid growth in the fall.  Rye is the easiest cool season annual to establish in thick residue.  It provides the most winter production and biomass.  Rye becomes unpalatable at the boot stage.  Often rye and ryegrass are mixed in equal proportions to provide growth over a longer period of time.

Wheat  - Wheat can be used for forage and grain production. It has good cold and drought tolerance, providing both autumn and winter production.  Typically, wheat is the least expensive winter annual.  Wheat has a low disease tolerance.

Ryegrass - Annual ryegrass is the easiest winter annual to establish.  It does not need to be planted in the soil as small grains do; however, production is earlier and greater when drilled.  Ryegrass is a high quality forage.  It has low winter production, but has the highest spring production.  Ryegrass is the only cool season annual adapted to poorly drained sites.  Overlapping growth periods of ryegrass and warm season plants can reduce vigor and yield of the warm season plants.

Species

Maturity

Cold Tolerance

Rye

1 (Earliest)

1 (Highest)

Wheat

2

2

Barley

3

3

Oaks

4

5 (Least)

Ryegrass

5 (Latest)

4

  Legumes

  (Inoculate legumes with appropriate inoculant.)

Crimson Clover - Crimson Clover is a versatile plant used as forage for soil conservation as a cover crop, as a source of pollen for bees, and for land beautification.  It is one of the most dependable, best yielding, and earliest maturing winter annual legumes.  Crimson clover will produce more forage at low temperatures than other clovers.  It is fairly tolerant of soil acidity, but does best when the soil pH is within the range of 5.8 to 6.5.  Ideally, crimson clover should not be grazed until the plants are four to six inches tall and should not be grazed closer than three inches.  Management for reseeding requires either that livestock be totally removed or that the stocking rate be greatly reduced during the seed production period.  Reduce or eliminate grazing pressure after the clover begins to bloom (usually early April).  Crimson clover seed mature within about 30 days of pollination.  If reseeding is desired once seed mature, the field can be grazed, cut for hay, or no tilled.  If mechanical harvest is planned, a cereal grain planted in a mixture with crimson clover is recommended.  Re-growth after mechanical harvest is usually poor, so only one harvest can be expected to contain significant quantities of clover.

Hairy Vetch - Hairy Vetch is a climbing, prostrate, or trailing annual.  It is relatively large seeded and able to establish even in heavy leaf deposition.  Hairy vetch is more cold tolerant than crimson clover.  During the winter, it produces little aboveground growth, but its root development continues, accounting for its drought resistance.  It tolerates pH as low as 4.9, but does best when the soil pH is within the range of 6.0-7.0.  Hairy vetch can grow on acid soils that will not sustain clover.  Hairy vetch is shade tolerant and can be overseeded in standing corn or as an understory cover crop in orchards.  Hairy vetch fed in high proportions may be toxic to livestock.  Root knot nematode and Reniform nematodes may increase successional vetch, so cereal rye is recommended prior to susceptible crops such as soybeans or cotton.  It can be a pest in fence rows or nursery crops.

Nutrient Contribution and Removal

Consider that grasses utilize more soil nitrogen, and legumes utilize both nitrogen and phosphorus.  Deep-rooted species provide maximum nutrient recovery (i.e., red clover, brassicas).

Soil microbial activity is much higher on young, relatively lush vegetation.  During microbial breakdown, nutrients held within the plant tissues are released and made available to the following crop.  Factors that influence the ability of microorganisms to break down organic matter include soil temperature, soil moisture, and carbon to nitrogen (C:N) ratio of plant material.  C:N ratios above 25:1 can result in nitrogen being tied up by soil microbes.  The lower the C:N ratio, the more N will be released into the soil for immediate crop use.  The higher the C:N ratio, the slower the release of nutrients to successional crops.

 Common C:N Ratios of Cover Crops

Organic Material

C:N Ratio

Young Rye Plants

14:1

Rye at Flowering

20:1

Hairy Vetch

10:1 to 15:1

Crimson Clover

15:1

Corn Stalks

60:1

Saw Dust

250:1

Cover crops sequester nutrients, and once their growth is terminated, release them slowly.   Legumes can be an excellent source of nitrogen, often providing more than 100 pounds of nitrogen per acre.   Reduce N rate by 50 to 70 pounds per acre following a legume cover crop. The maximum quantity of nitrogen is accumulated when legumes are allowed to reach the late bloom stage prior to being killed.

Seeding Methods

Cover crops can be tilled and drilled, no-till drilled, or tilled and broadcast seeded and followed with a cultipacker.  Typically, cool season annual grass production is earliest on a prepared seedbed followed by no-till plantings into crop residue, and the latest growth is winter annuals overseeded into summer grass.  Overseeding winter annuals into cool season perennial grasses is typically not recommended due to competition.  No-till seedings are most soil conserving, provide the firmest surface for livestock, and increase organic matter.

For most purposes, acceptable benefits are usually accomplished when the plant density is at least 25 stems per foot, the combined canopy and surface cover is at least 60 percent, and the aboveground (dry weight) biomass production is at least 2,700 lbs./acre.

 

Recommended Seeding Rates and Dates for Cover Crops:
           

Crop

Varieties

Rates per Acre

Seeding Dates

Annual Lespedeza

Kobe

Korean

20-30 lbs.

20 lbs.

Feb. 15-April 15

Arrowleaf Clover

Meechee, Yuchi

5-8 lbs. (scarified)

Aug. 15-Oct. 1

Barley

Starling

For winter cover, grain, or spring grazing 1.0-1.5 bushels

-----------------------------

Fall grazing  3-4 bushels

Sept. 15-Nov. 1

No-till drilled Sept. 15-Oct. 20

-----------------------------------------Conventional or broadcast

Sept. 1-Oct. 1

Buckwheat

Common Gray, Silver Hull, Japanese

35-50 lbs.

June 1-Aug. 1

Cowpeas

Whipporwill, Brabham, Clay

1.5-2 bushels Broadcast

0.5 bu. in rows

May 20-June 20

Crimson Clover

Dixie, Chief,  Tibbee

15 lbs. winter cover,

20 lbs. Forage

Aug. 1-Oct. 15

Millet, Browntop

 

25-40 lbs.

May 1-July 1

Millet, Foxtail

German

20 lbs. or 15 lbs. + 1 bu. Soybeans

May 1-July 1

Oats:

     Fall Seeded                                    --------------------------

     Spring Seeded

FFR Southern States 76-30                

 

-------------------------------------

Don, Ogle, Larry

2 bushels for grain

4-6 bushels for fall pasture                            ------------------------------------

2-3 bushels

Sept. 1-Oct. 1

                                                       -----------------------------------------

Feb. 20-March 15

Pearlmillet

Millex 24, Millex 32

10-15 lbs. Drilled

20 lbs. broadcast

May 1-July 15

Rape (Forage)

Dwarf Essex

6-8 lbs.

Feb. -March;

Aug. -Sept.

Rapeseed (Oil)

 

5-6 lbs.

Sept. 1-Oct. 10

Red Clover

Cinnamon, Reddy, Redman, Redland III

8-12 lbs.

Aug. 15-Oct. 1

Feb. 15-April 1

Rye

 

Wheeler, FFR 20/20, Vitagraze Winter Magic, Rebel, Volunteer Magic

Winter cover, spring grazing 1.0-1.5 bu.     

------------------------------------Fall grazing 2-3 bushels

Sept. 15-Nov. 20 no-till drilled

Sept. 15 Nov. 10 Overseeded           

-----------------------------------------

Aug. 15-Oct. 15

Ryegrass, Annual

Marshall, Surrey

20-30 lbs.

Aug. 15-Oct. 10

Sudangrass

Trudan 8

30-48 lbs. Broadcast

20-30 lbs. Drilled

April 20-July 1

Vetch

Hairy

20 lbs. Winter cover

30 lbs. Forage

Aug. 15-Oct. 15

Wheat

 

(Expected damage from Hessian Fly and/or barley yellow dwarf prevents planting earlier than Oct. 15 for grain production.)

 

 

 

 

 

 

Wheat (also barley or rye)

See current U.T.  publication for Field Crop Varieties.

For grain or spring grazing

1-1.5 bushels                            ------------------------------------

1-1.5 bushels       

------------------------------------

1.5-2.0 bushels

                                            ------------------------------------

For winter cover

1-1.5 bushels                            ------------------------------------

1-1.5 bushels                           

                                            ------------------------------------

1-1.5 bushels                            ------------------------------------

For fall grazing

2-3 bushels                              ------------------------------------

For cover, wildlife enhancement, or fall grazing: 1.5-3 bushels

Increase seeding rate 50% if using combine-run seed.

Oct. 15-Nov. 10

No-till drilled                    

--------------------------------------------

Oct. 15-Nov. 1 Tilled

--------------------------------------------

Oct. 15-Nov. 1

Overseeded no till

--------------------------------------------

Sept. 15-Nov. 10

No-till drilled                                 --------------------------------------------

Sept. 15-Nov. 1

Overseed no till                             --------------------------------------------

Sept. 15-Oct. 20 Tilled                  --------------------------------------------

Sept. 1-Oct. 1

                                                      -----------------------------------------

Aug. 15-Oct. 15

Wildrye, Virginia

Omaha

15-20 PLS lbs.

Aug. 15-Oct. 15

Winter Peas

Austrian

45-60 lbs.

Aug.-Oct. 1

 

                        


Copyright 2018 - Madison County SCD All Rights Reserved  -  This site was last updated: March 13, 2018  -   Contact the Webmaster   -   Policy Statements

 

    Madison County Soil Conservation District    -    313 North Parkway    -   Jackson, Tennessee 38305   -  (731) 668-1544 ext. 3   -   FAX: 1-855-584-5847