One natural way to manage weeds, pests, soil erosion, and improve soil fertility and quality, is with the use of cover crops.
Cover crops are important in helping to achieve healthy soil for the permaculture/organic farmer or gardener.
What are Cover Crops?
Using cover crops in farming methods dates back at least as far as Roman times . You can grow these crops are alongside, secondary to, food-producing and cash crops.
These plants cover the ground, preventing erosion and dehydration. They also help to promote good soil while also providing grazing and fodder for farm animals.
Soil improvement is the main aim of planting cover crops.
- Weed suppression. The residue from these plants can block sunlight, smothering weeds.
- Legume cover crops recycle and add nitrogen to the soil.
- Aeration is a further benefit, preventing the soil from compacting and allowing other plants to thrive.
- Conserve soil moisture. Cover crops trap water, allowing it to filter deep into the soil.
- Hold the soil in place, thereby preventing soil erosion.
- Green manures add nutrients by increasing soil organic matter.
- Help eradicate diseases and pests in the soil by breaking the cycle.
- If properly managed, garden cover crops can also provide mulching benefits.
- Living mulches also serve as great ground covers.
Types of Cover Crops
Cover crops fall into four main categories: grasses, legumes, brassicas, and non-legumes broadleaves.
These are not only useful but are also very attractive plants. For the practical gardener or farmer, grasses and cereals are useful in reducing erosion.
They also work for suppressing weeds and producing residue high in nitrogen. Additionally, the residue left after cutting provides a nutrient-rich mulch that helps protect the soil from adverse weather conditions.
This category includes rye and sorghum grasses plus oats, wheat, and barley cereal crops.
These plants are grown mostly for their ability to enrich the soil with nitrogen. They fix nitrogen from the atmosphere and supply it to the soil.
Additionally, living plants add organic matter, attract pollinators and beneficial predatory insects, and help prevent erosion of the soil.
This group includes clovers, vetches, peas and soybeans, mucuna vine, and alfalfa.
This category includes the eye-catching yellow fields of rapeseed (canola) and mustard. Generally, these are successful cover plants cultivated especially to support growth in vegetable crops.
Forage radish has many useful properties. These include root penetration that improves friability of the soil and nutrient uptake. Turnips and marigolds are other crops in this group.
These broadleaf crops make green manure, recycle existing soil nitrogen, and bind the soil together. However, they cannot fix nitrogen from the atmosphere.
Species include buckwheat, annual ryegrass, cereal rye, and barley.
Crop monitoring will help determine which cover plant or group suits the specific needs and conditions for vegetable gardens.
In general, those most suitable for summer growth are buckwheat, cowpeas, sorghum-sudangrass, and wheat. Some summer crops also provide fodder for livestock.
Winter conditions can badly affect some crops like canola. Others, however, like clovers, especially crimson clover, annual rye, some vetches, and Austrian peas are suitable.
Winter wheat can be grown in any suitable environment. After producing a beneficial greensward in early spring, they can be killed off and tilled in to enrich the soil for the summer crops.
Experienced gardeners will know exactly the right moment when the growing benefits of these crops have reached their peak and are going to seed. This is the time to kill off the plants.
Crops that naturally die of the cold form a nutritious surface mulch that protects the ground from erosion. Moreover, those that are winter-killed by other means can leave the ground free for early spring.
Crop residue, depending on the type, may be tilled in to enrich the soil. Mowing is the most common method of crop kill. However, a labor-saving useful way is to allow animals to graze.
Benefits of Grazing
Sowing cover crops for grazing farm animals has many benefits. It is primarily a cost-effective way of feeding livestock.
Grazing animals supply organic matter and help reduce compaction by their movement over the ground. Additionally, dung produces biological activity from beetles and earthworms benefitting the soil.
Cover plants for grazing include cereal grains like wheat, oats, barley, and millet. Additionally, there are legumes such as alfalfa, peas, beans, and clovers.
Specific Uses of Cover Crops
Establishing objectives when planting (buy seeds here) can help gardeners and farmers select the right plants.
- Nitrogen fixation (assimilating atmospheric nitrogen). Legumes such as cowpeas, velvet beans, hairy vetch, and clovers. Cabbages and other brassicas require a lot of nitrogen so planting legumes first is beneficial. Tomatoes also absorb a lot of nutrients and benefit from prior planting of nitrogen fixers.
- Moisture improvement and retention. Crimson and white clovers, winter wheat, rye, and rapeseed.
- Reducing compaction of the soil. Turnips, radishes, canola, and sunflowers.
- Weed cover and short-term cropping. Oats and red clover or quick-growers like buckwheat.
- Residue cycling. The brassicas are best for this, e.g. radishes, turnips, rapeseed, and mustards. Most brassicas are winter-killed providing nitrogen-rich residue. Tender plants like buckwheat will rot down and be absorbed into the soil speedily but others like carbon-producing sorghum take longer.
- Long-period cropping. Mixes of small cereal grains like barley or rye with nitrogen-fixing legumes such as vetch, clovers, or cowpeas.
Cover cropping on a smaller scale need not be daunting. Start with something like buckwheat. Easily sown and fast-growing, buckwheat thrives well in moist and cool conditions.
Moreover, it rapidly smothers weeds and the small white flowers attract beneficial predatory insects and pollinators like bees and butterflies.
Easily killed and incorporated into the earth, buckwheat leaves valuable nutrients for soil enrichment.
For the home garden, you can also experiment with annual ryegrass.
Cover cropping has a central place in permaculture farming and gardening. Sown in rotation throughout the year, these crops are grown to repair and/or enrich soils by improving the structure and imparting nitrogen, carbon, and other nutrients.