Cover crops for specific purposes

Since cover crops have different functions, it is important to determine what thecrop is expected to do. Is the intent to add organic matter to the soil? To add nitrogen to the cropping system? To stimulate soil biological activity? To protect the soil during the winter months?

 

Cover crops for weed suppression

Several cover crops are considered “smother” crops because they are used to control or suppress weeds. Crops that give the best results are those that are quick to germinate, provide rapid ground cover and form thick canopies.
• Vetch
• Saia Oats
• White Mustard
• Teff
• B1 Burgundy Beans
• Phacelia

 

 

Cover crops for mulches

The properties of the cover crop residues are very important as they have a direct influence on the outcome of organic matter decomposition (humification and mineralization) and other plant nutrition dynamics. Young and succulent green manure crops with a low C:N ratio will feed soil micro-organisms, while a mature, fibrous green manure crop such as cereal straw will form stable organic matter but provide little stimulation of soil biological activity.
• Saia Oats
• Rye
• Triticale
• Rhodes Gras
• Panicum Maximum
• B1 Burgundy Beans
• Dolichos Beans
• Forage Sorghum
• Phacelia

 

 

Nitrogen fixing cover crops

Legumes such as lupines, clover, vetches and cow peas that can fix atmospheric nitrogen, are also able to supply nitrogen to subsequent crops. When sources of manure or compost are not readily available, legume crops can be inserted into a crop rotation to supply nitrogen to the cash crops. Nitrogen fixing legume crops must be inoculated with rhizobium bacteria at planting. Legume crops require specific strains of fresh or well preserved inoculants. Inoculation is particularly important if the legume crop was never
grown previously on the site.
• Lupins
• Vetch
• Medics
• Serradella
• Clovers
• Faba Beans
• Velvet Beans
• Soya Beans
• Cowpeas
• B1 Burgundy Beans
• Sunn Hemp
• Dolichos Lablab

 

 

Low maintenance cover crops

Turf type grasses are popular cover crops used in orchards due to the low maintenance of the plant. These grasses usually forms a uniform surface that provides good ground cover as well as weed suppression. Although the idea is to help with soil erosion, water logging, weeds and good ground cover, the popularity remains the fact that it is a very persistent cover crop with low maintenance.
• Dwarf Fescue
• Creeping Red Fescue
• Paspalum
• White Clovers
• Strawberry Clover

 

 

Bio fumigation cover crops

To interrupt pest life cycles, it is important to select cover crops of a different family than that of the future cash crop so that they do not harbour pests that can negatively impact the cash crop. Cover crops may also attract beneficial organisms that prey upon or parasitize pest species.

• White Mustard
• Bladrammenas
• Saia Oats
• Brassica juncea
• Sunn Hemp
• Rhodes Grass

 

 

Decorative cover crops

The right cover crop can even look decorative among other ornamental plants. The show from crimson clover, its blossoms clustered tightly on upright stalks like strawberry popsicles, is so spectacular that you would hardly suspect that it was improving the soil.
• Crimson Clover
• Sunflower
• Phacelia

 

Cover crops for water logged areas

Faba bean tolerates water logging better than other grain legumes such as field peas and lupines. It also tolerates acid soil types better than other grain legumes. The Faba bean plant is tall (may grow to over 1m under optimum conditions), erect and multi-stemmed from basal branches. It has a well-developed taproot which produces an extensive fibrous root system. Plants can flower profusely and flowering may last for up to 5 weeks, depending on soil moisture and air temperature.

• Faba Beans
• Fescue
• Paspalum
• Birdsfoot Trefoil
• Phacelia
• Strawberry Clover
• Balansa Clover

 

Cover crop problems

The use of cover crops are not without some potential problems. Many annual cover crops must be mowed before they produce viable seeds which could become weeds. Some cover crops have allelopathic properties that can have detrimental effects on the cash crops that follow. Large amounts of cover crop residues can cause significant problems during seeding of the next crop. Precision seeders are particularly sensitive to seedbed conditions with excessive crop residues. Nitrogen can be tied up during decomposition of incorporated fibrous plant material to the detriment of the cash crop. Poorly selected cover crops can attract, stimulate or harbour pests that can negatively impact the following cash crop.