Table 1.10-6. Characteristics of common cover crops
| Species | Life cycle¹ | Hardy through zone |
Seeding rate² (lb/A) |
Seeding depth (inches) |
Seeding date |
N-capture/ fertilizer equivalency (lbs/A) |
Advantages | Disadvantages |
|---|---|---|---|---|---|---|---|---|
| ¹A=annual; WA=winter annual; B=biennial; SLP=short-lived perennial; LLP=long-lived perennial; NFT= no frost tolerance ²Higher rates may be necessary for broadcast seedings |
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| Grasses (Cool season) | ||||||||
| Cereal rye (Secale cereale L.) | WA | 3 | 112 (2 bu) | 1–2 | Sept.–Nov. 1 | Excellent nutrient scavenger (esp. N) | Most cold tolerant of commonly used cover crops; providing living cover in winter and spring, erosion control, weed suppression, nutrient recycling, organic matter improvement, soil tilth improvement; earliest small grain to mature | Regrowth may occur if not completely controlled; explosive growth in spring poses termination challenges; possible following crop suppression due to allelopathy or nutrient tie-up; may attract some insect pests. |
| Winter wheat (Triticum aestivum L.) | WA | 4 | 120 (2 bu) | 1–2 | Sept.–Nov. 1 | Excellent nutrient scavenger (esp. N) | Cold tolerant in most of PA; rapid growth; common varieties not as tall as rye and therefore easier to manage; provides living cover in winter and spring, erosion control, weed suppression, nutrient recycling, organic matter improvement, soil tilth improvement | Accumulates lower amounts of biomass than rye; possible following crop suppression due to nutrient tie-up; may attract some insect pests; matures after triticale |
| Winter triticale | WA | 3 | 120 (2 bu) | 1–2 | Sept.–Nov. 1 | Excellent nutrient scavenger (esp. N) | Intermediate between wheat and rye | Intermediate between wheat and rye; matures after barley |
| Winter barley (Hordeum vulgare L.) | WA | 6 | 120 (2.5 bu) | 1–2 | Sept.–Oct. 15 | Good nutrient scavenger | Cold tolerant in southern parts of PA; common varieties not as tall as rye and therefore easier to manage in spring; provides living cover in winter and spring, erosion control, weed suppression, nutrient recycling, organic matter improvement, soil tilth improvement | Winterkill is possible; accumulates lower amounts of biomass than wheat; possible crop suppression due to nutrient tie-up; matures after cereal rye |
| Spring oats (Avena sativa L.) | SA | 8 | 100 (3 bu) | 1–2 | Aug.–Sept. 15 | Average nutrient scavenger | Very easy to manage because winterkills; provides erosion control, weed suppression, nutrient recycling, organic matter improvement, soil tilth improvement in fall, rapid growth in cool weather; ideal for quick fall cover or nurse crop with legumes; may produce more biomass in fall than other winter small grains if planted early | Winterkills in most of PA, no living root system in winter and spring; erosion control may be limited in spring; high lodging potential; susceptible to disease and insect pests |
| Annual ryegrass (Lolium spp.) | WA | 6 | 20 | 0.25–0.5 | Aug.–Sept. 15 | Good nutrient scavenger | Cold tolerant in southern parts of PA; varieties not as tall as rye; provides living cover in winter and spring, erosion control, weed suppression, nutrient recycling, organic matter improvement, soil tilth improvement, high-quality fodder | May winterkill; may be difficult to control; low heat tolerance; may harbor insects; may reseed and become weed |
| Grasses (warm-season) | ||||||||
| Pearl millet (Pennisetum glaucum) |
SA |
NFT |
10-15 |
0.25-0.50 |
June-early Aug. |
Excellent scavenger |
Heavy tillering, drought-tolerant, and adapted to low-fertility, sandy soils; can grow to 12 feet tall depending on variety; matures in 60–70 days; good forage |
Very large biomass production can be challenging to manage |
| Sudan-grass (Sorghum bicolor) |
SA |
NFT |
35-40 |
1 |
June-early Aug. |
Excellent scavenger |
Quick growth; scavenges nitrogen; competes with weeds; large biomass producer; alleviates compaction; can grow 12 feet tall |
Prussic acid production when young, drought stressed, or frosted—do not graze then; large biomass production can be challenging to manage |
| Japanese millet (Echinochloa frumentacea) |
SA |
NFT |
20-25 |
0.25-0.50 |
June-early Aug. |
Good scavenger |
Very fast growth, mature and up to 4 feet tall in 45 days; resembles barnyard grass; suppresses weeds |
Can become a weed if let go to seed; grows poorly on sandy soils. |
| Legumes | ||||||||
| Hairy vetch (Vicia villosa Roth) | WA | 4 | 20-25 | 1–2 | Aug.–early Sept. | 80–160 | Most cold tolerant and high biomass production; above-average drought tolerance; adapted to wide range of soil types; combines well with small grains | Requires early fall establishment; slow to establish; matures in late spring; high P and K requirement for maximum growth; can harbor pests; potential weed problem in winter grain; glyphosate not full-proof for control |
| Crimson clover (Trifolium incarnatum L.) | WA/SA | 6 | 10-15 | 0.25–0.5 | Aug.–early Sept. | 70–130 | Fairly cold tolerant; rapid fall growth; high biomass production; matures midspring; above-average shade tolerance; forage use (no bloat); good nematode resistance | May winterkill; requires early fall establishment; poor heat and drought tolerance; residue has tough stems, difficult to no-till plant into |
| Red clover (Trifolium pratense L.) | SLP (2–3 yrs) | 4 | 8–10 | 0.25–0.5 | Feb.–June | 70–120 | Survives winter; deep taproot; soils; tolerates wet soil conditions and shade; forage use, especially if mixed with grass | Needs to be established before midsummer because initial growth slow; high P and K requirements for maximum growth; hard seed can persist creating volunteer problems; pure stand forage causes bloat; vulnerable to some pathogens, insects |
| Field peas (Pisum spp.) (e.g. Austrian winter pea) | SA/WA | 7 | 50–80 | 1.5–2.0 | Aug.–Sept. 15 | 50–150 | Rapid growth in cool weather; versatile legume; interseed with cereal and Brassica spp.; used as food or feed | May winterkill; shallow root system; sensitive to heat and humidity; susceptible to diseases, insect pests |
| Cowpea (Vigna uncuiculata) |
SA |
NFT |
40 |
1.4-2 |
June-early Aug. |
50-100 |
Also known as black-eyed peas; adapted to wide range of soil conditions; deep taproot can extract moisture from deep in profile |
Performance has been erratic in PA trials |
| Other Crops | ||||||||
| Buckwheat (Fagopyrum esculentum Moench) | SA | NFT | 35–50 | 0.5–1.5 | Spring or late summer | Fair to good nutrient scavenger (esp. P, Ca) | Grows on wide variety of soils (infertile, poorly tilled, low pH); rapid growth; quick smother crop and good soil conditioner | Limited growing season; not winter hardy; limited biomass accumulation; frost sensitive; poor growth on heavy limestone soils; occasional pests |
| Brassicas (Cruciferae family) (e.g. rape, radish) | WA | 8 | 5–12 | 0.25–0.5 | Spring or fall | Good nutrient scavenger (esp. N, P, Ca) | Quick establishment in cool weather; prevent erosion in fall (radish) and spring (canola, rape); radish easy to manage because winterkills; deep, thick root systems; compaction alleviation; nutrient cycling; weed suppression | Radish winterkills in all of PA, while canola/rapeseed may winterkill in northern parts of PA; radish leaves soil bare in spring, therefore mix with a small grain |
