Cover Crops: Sweet Clover
Table of Contents
- Description: Family
- Growth Habits
- Sensitivity to Herbicides
- Weed Control
- Benefits and Cautions
- Getting Started
- Related Links
Description
Figure 1. Sweet Clover in flower.
Figure 2. Sweet Clover by roadside.
Family
- Leguminosae;species Melilotus spp
Growth Habits
Germination
- White sweetclover have hard shells and need to be scarified prior to germination
- Require the same strain of rhizobial bacteria as alfalfa for inoculation
Top Growth
- Yellow sweet clover: 30-280 cm
- White sweet clover: 100-200 cm., annual or perennial, grows as a 1 m stem
- Flowers May-September; seeds in mid-to late fall
Root System
- Strong taproot system – can penetrate up to 2 m
- Can penetrate compacted silty and clayey soils
Overwintering
- Seldom winterkills
Site Suitability
- pH tolerance 6.5 to 7.5;
- Average annual temperature range between 5° and 22° C
- White sweetclover does well does on a wide range of soil textures
- Tolerates calcareous conditions;
- Sweetclovers perform well in moderately well drained conditions
Sensitivity to Herbicides
- There are no herbicides available that are safe for use on sweet clover and control these broadleaf weeds.
- Sweet clover is also sensitive to the soil residues of atrazine and some Group 2 herbicides.
Weed Control
- Sweet clover is frequently underseeded into a cereal crop and
any weed control herbicide program must be:
- safe to the cereal crop
- effective on the weeds
- safe to the cover crop
- Usually the major weed control problems will be with winter annuals in fall seeded crops and with annual broadleaf weeds in spring cereals.
Benefits and Cautions
Nutrient Management
- Fixes nitrogen and should be credited for N-additions; believed to move P and K to the root zone via its tap root system
Pest Management
- Attracts beneficial flowering insects
Organic Matter
- Biennial whites yield 2,200-3,500 lbs/ac (Yr. 1) and 2,200-8,100 lbs/ac (Yr. 2)
- Yellow sweetclover 4,200-4,500 lbs/ac (Yr. 1) and 5,500-8,500 lbs/ac (Yr. 2)
Erosion Control
- Strong taproot said to reduce hard pan problems
Soil Moisture
- Shows intermediate values for water use efficiency
Getting Started
Establishment
- Plant in early spring – March-April
- May need to be scarified
- Needs to be covered lightly
- Planting rate: 10-30 lbs/ac, depending upon variety. Most require 8-10 lbs/ac
- Seeding depth ~ 1.25 cm
- Can be underseeded into corn
Cost & Availability
- Inexpensive to moderate cost (US $0.80 to $ 2.50/lb.)
- Most varieties suitable to Ontario conditions are widely available
Related Links
For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca