Corn

Description

Family

  • Annual grass.
Damage to corn leaves.
Figure 1. Damage to corn leaves.

Cover crop use

  • After early harvested crops, when soil moisture and nitrogen available.
  • Use discarded or old seed.

Growth habits

Germination

  • A relatively large seed, it requires some moisture to get going.
  • Needs warm soils, temperature greater than 10°C for germination and growth.

Top growth

  • When planted as a cover crop will behave more like a grass like sorghum sudan.

Root system

  • Fibrous.

Overwintering

  • Winterkills.

Site Suitability

  • Tolerant of most soil types, germination and emergence in mid to late summer on heavy clay soils challenging.

Control options

  • Tillage, frost and burndown herbicides can be used for control.

Sensitivity to herbicides: Weed Control

  • There are many herbicides registered for use in corn but good weed control for a cover crop should not be expensive and may not be needed. Use narrow rows and a high enough plant population to establish a vigorous crop canopy as soon as possible.

Benefits and concerns

  • Corn can make an inexpensive and effective cover crop if seeded early. However it is very sensitive to frost. If seeding a fragile, erosion prone area, mix with a cover crop like rye or wheat to ensure that the cover is stable.
Patchy field of corn cover crop.
Figure 2. Patchy field of corn cover crop.

Nutrient management

  • High uptake of soil nitrogen once past 3 to 4 leaf stage.

Pest management

  • Some concern about harbouring corn pests like armyworm in late summer.

Organic matter

  • Best used as a green manure crop.
  • Biomass return highly dependent upon planting date, seeding rate and first frost.

Erosion control

  • Not a good option.

Getting started

Establishment

  • Plant similar to sorghum sudan.
  • Use drill rather than rows to get fastest cover possible.
  • Seed heavy to get fast cover and to compensate for low seed viability.

Cost and availability

  • If discard seed available locally — seed should be inexpensive or free.

Fescues

  • Often used in erosion control projects to stabilize banks and provide cover on buffer strips or grassed waterways.
  • Also used for sod strips in orchard production.
  • Low growing varieties greatly reduce the need for mowing.

Triticale

Description

Family

  • Grass — Triticeae.

Cover crop use

  • Similar to other spring cereals is using spring triticale.
  • Winter triticale — overall ground cover after harvest, will establish late into the season.
  • As a forage crop.

Growth habits

Germination and emergence

  • Will germinate in cold temperatures –1 to 2°C but vegetative growth requires 4°C.

Top growth

  • Taller than wheat, mature crop 120 to 150 cm in height.
  • Warm wet weather in spring can cause rapid growth from 15 cm to 1 m in a short period of time.
  • Long day plant — will flower when daylight hours exceed 14 hours and temperatures average 5 to 10°C.
  • When flowering starts — vegetative growth stops.

Root system

  • Fibrous.
  • Extensive — can cover 1 m radius and 2 m depth of soil.

Overwintering

  • Does not winter kill.
  • As living tissue, there is greater resistant to sand abrasion over winter.
  • Resumes growth in spring faster than wheat.

Site suitability

  • More drought tolerant than wheat or oats.
  • Tolerates a wide range of soil conditions but does best in well drained light soils — sands, loamy sands, sandy loams and gravelly soils.

Control options

  • Can be harder to kill than other cereals — timing and control options are critical.
  • Mow when crop goes into flowering stage (vegetative growth has stopped) for non-chemical control.
  • Requires careful management of chemical control in the spring.
  • Low rates of glyphosate can kill the plant — but leave it standing. This prolongs protective features longer. High rates of glyphosate will knock the crop down leaving less wind protection.

Sensitivity to herbicides: Weed control

  • There are many herbicides registered for use in wheat but good weed control for a cover crop should not be expensive and may not be needed.
  • Establish a vigorous crop canopy to smother out weeds.

Benefits and concerns

Nutrient management

  • Best cool season cereal crop for taking up leftover nitrogen from previous manure application(s).
  • Can tie up nitrogen in spring when needed by following crop.
  • Rye may help to increase the concentration of potassium at the surface due to its extensive root system.

Pest management

  • Competitive growth habits — good for suppressing weeds.
  • Allelopathic effect — prevents weed germination and growth, but can have allelopathic effect on other grass-like crops (for example, corn).

Organic matter

  • Large volumes of plant biomass returned to soil.

Erosion control

  • Wind abatement strips.
  • On tomato beds.
  • As strips in tobacco or vegetable fields.
  • Preferred because it does not winterkill and is resilient to sand blasting.

Soil moisture

  • More drought tolerant than wheat or oats.

Getting started

Establishment

  • Shade tolerant — can be overseeded into a standing crop of corn before leaf drop.
  • Only cover crop that can be planted in the late fall and still provide some soil cover, although the protection may not be highly effective until early spring.
  • Cold tolerant — established rye can withstand temperatures of –35°C.

Cost and availability

  • Seed is relatively inexpensive and readily available.