Table 1.
Primary ecosystem functions provided by roots of cover crop species
| Family | Name | Soil erosion protection | Increased SOM content | Nutrient and water 'catch' | Topsoil structure remediation | Subsoil structure remediation | Soil pathogen resistance | Biological N fixation | Notes |
|---|---|---|---|---|---|---|---|---|---|
| Cool‐season annual grains | |||||||||
| Poaceae | Barley (Hordeum vulgare) | x | x | x | x | x | x | Planted in spring or fall, commonly mixed with peas, oats, and crimson or red clover | |
| Oat (Avena sativa) | x | x | x | x | x | Planted in spring or fall, commonly mixed with alfalfa, hairy vetch and field peas | |||
| Wheat, triticale, spelt (Triticum spp.) | x | x | x | x | x | Planted in spring or fall, commonly mixed with peas, vetch, and clover | |||
| Winter rye (Secale cereale) | x | x | x | x | x | Planted in fall | |||
| Warm‐season annual grains | |||||||||
| Polygonaceae | Buckwheat (Fagopyrum esculentum) | x | x | x | x | Planted in spring through summer | |||
| Sudangrass, sorghum‐sudangrass (Sorghum bicolor × S. bicolor var Sudanese) | x | x | x | x | x | x | Planted in spring through summer, mix with a buckwheat crop or with forage soybeans and cowpeas | ||
| Japanese millet (Echinochloa esculenta), pearl millet (Pennisetum glaucum), foxtail millet (Setaria italica) | x | x | x | x | Planted in spring through summer, commonly mixed with forage soybeans and cowpeas | ||||
| Teff (Eragrostis tef) | x | x | x | x | Planted in spring through summer | ||||
| Brassicas | |||||||||
| Brassicaceae | Mustard, canola (Brassica spp.) | x | x | x | x | x | Planted in spring or fall | ||
| Arugula (Eruca sativa) | x | x | x | x | x | Planted in fall | |||
| Pennycress (Thlaspi arvense) | x | x | x | x | Planted in spring or fall | ||||
| Forage radish (Raphanus sativus), forage turnip (Brassica rapa) | x | x | x | x | x | Planted in fall | |||
| Grasses | |||||||||
| Annual ryegrass, perennial ryegrass (Lolium spp.) | x | x | x | x | x | Planted in spring or fall | |||
| Orchardgrass (Dactylis glomerata), timothy (Phleum pratense) | x | x | x | x | Planted in spring or fall | ||||
| Legumes | |||||||||
| Fabaceae | Field pea (Pisum sativum) | x | x | x | x | x | x | Planted in spring or fall | |
| Soybean (Glycine max), cowpea (Vigna unguiculata) | x | x | x | x | x | x | Planted in spring through summer | ||
| Alfalfa (Medicago sativa) | x | x | x | x | x | Planted in spring or fall, is best grown with a small grain crop or perennial grass | |||
| Hairy vetch (Vicia villosa) | x | x | x | x | x | x | x | Planted in fall, commonly planted with winter cereals. | |
| Chickling vetch (Lathyrus sativus) | x | x | x | x | x | Planted in spring through summer | |||
| Perennial clovers. Red clover, white clover, alsike clover (Trifolium spp.), yellow sweetclover (Melilotus officinalis) | x | x | x | x | x | x | Planted in spring or fall | ||
| Annual clovers. Crimson clover, berseem clover, subterranean clover (Trifolium spp.) | x | x | x | x | x | x | Planted in spring or fall | ||
Note: Red colour indicates high performance for a particular ecosystem service. Adapted from NRCS Cover Crop plant specification guide: https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1081555.pdf