#204Cover crops
204⸱AConcept
- Balances soil humidity and temperature
- Reduces erosion
- Suppresses weed growth
- Improves soil structure and organic matter
- Improves soil life
Cover crops, or living mulch, refer to a wide range of annual or perennial plants that can be sown to cover bare ground.
Bare and unprotected soil can lead to soil erosion through wind and rain and high soil temperatures due to direct sun exposure and dryness. Climate change is increasing these impacts.
Sowing cover crops between coffee rows helps adapt to these climate change impacts. It protects the soil from direct sunlight and rain impacts, helps to reduce soil erosion, and keeps the soil moist and temperate. By penetrating the ground, the cover crops’ roots increase rainwater infiltration and create soil organic matter when they break down. Living mulch also slows down the development of weeds. Once established, the cover crops can be cut back and the residues can be used as mulch to cover the soil around the coffee trees.
Different cover crops provide different additional benefits: Leguminous crops add nitrogen to the soil. Grass-like crops produce large amounts of residue and roots which help add organic matter to the soil. Their wide and strong – fibrous – roots help to penetrate compacted soils. Also thanks to their root systems, they effectively scavenge nutrients, especially nitrogen and leftovers from previous crops. After cutting down the grasses and leaving them as mulch, these nutrients become again available to the coffee plants. If opting for food or fodder crops, they can provide food, animal feed, or additional income.
An indirect benefit of cover crops is that it reduces the incidence and severity of many pests and diseases. This is, first, because it reduces moisture and nutrient stress for the plant which increases its resistance, secondly, because it improves the biodiversity in the soil which helps against soil-borne pathogens.
204⸱BVideos
204⸱CTo be considered
The cover crop species used should be robust, have low nutrient and water requirements, and none or only little need to be fertilized or irrigated. This keeps the management time and costs low. They however require some management to ensure that they do not grow too much and end up competing with the coffee trees in terms of water and nutrients.
Also, it should be considered that some cover crops can be invasive, they can climb and choke coffee trees.
Soil improvements should be visible after already one or two years. The soil will have a looser structure and there will be signs of greater biotic activity, e.g. fungi and invertebrates.
Timing
The cover crops should be sown at the start of the rainy season.
204⸱DImplementation
Materials
Recommended cover crop species are:
Brachiaria ruziziensis
Brachiaria ruziziensis is a grass that is grown throughout the humid tropics. It has been used in regions of Brazil as a cover crop and on some Guatemalan and Hondurean farms. It is more drought-resistant than coffee and presents a deep root system that promotes the nutrient cycling from deeper layers to the soil’s surface.
Attention: Make sure to choose varieties that produce only sterile seeds when using grasses as Brachiaria Ruziziensis.
Cajanus cajan (Feijão Guandu / Pigeon pea)
Cajanus cajan (Feijão Guandu) is a legume (Fabaceae). Therefore, it has the capacity to incorporate nitrogen into the soil that can be used by coffee. One advantage of Gandul is its high growth as a shrub that allows it to provide temporary shade for coffee. This shade reduces the temperature of the environment. It is required to prune it every 6 months to create a shade that benefits the coffee.
Crotalaria sp. (Crotalaria)
Crotalaria sp. (Crotalaria) is a legume (Fabaceae). Therefore, it has the capacity to incorporate nitrogen into the soil that can be used by coffee. One advantage of Crotalaria is its high growth as a shrub that allows it to provide temporary shade for coffee.
Raphanus sativus L. (Nabo forrageiro/Radish)
Raphanus sativus L. (Nabo forrageiro/Radish), has long roots that reach deep into the soil. It therefore serves as a soil conditioner and makes subsequent crops reach water more easily. It can be used as a fodder crop.
Fagopyrum esculentum (Trigo Mourisco / Buckwheat)
Fagopyrum esculentum (Trigo Mourisco / Buckwheat) is an annual flowering plant and belongs to the family Polygonaceae. Its grain-like seeds serve as a “pseudocereal” and can be used as food.
Milhete / Millet
Millet belongs to the group of small-seeded grasses. It can be used as human food or fodder crops.
Cover crop seeds are also available as commercial ready-to-use mixtures in the market.
204⸱1Preparation
It is advisable to have sufficient space between the coffee rows (at least 2.5 m / 8 ft (Arabica) or 3 m / 10 ft (Robusta)), to have ideal conditions for the development of the cover and the coffee crop.
204⸱2Sowing
Brachiaria as cover crop
204⸱3Management
Climbing cover crops can be grown on trellises.
204⸱4
204⸱5
Example of cut Brachiaria plant material in Brasil
204⸱6
- During long dry seasons, it is best to cover the ground with a thick layer of cut material to reduce evaporation to a minimum.
204⸱EEconomic benefits
Lower labor costs
This tool might cause some extra workload and material costs in the beginning. However, its advantages ultimately result in lower labor requirements and therefore lower costs.
Lower fertilizer costs
This tool allows for a lower demand for synthetic fertilizers and therefore saves input costs over time.
Lower herbicide costs
This tool reduces the demand for pesticides and therefore saves input costs over time.
Higher coffee yield
The effects of this tool can lead to a higher coffee yield and therefore a higher income.
Additional income source
This tool has the potential to provide an additional income.
204⸱FGreen benefits
Less synthetic fertilizers needed
This tool reduces the need for syntheticfertilizers. This reduces carbon emissions and water pollution, improves soil life, and saves resources.
Less herbicides needed
This tool reduces the need for herbicides. This reduces water pollution, protects the ecosystem, improves soil life, and saves resources.
Better soil life
This tool helps improve soil life (microbes, earthworms, etc.). This plays a vital role in plant nutrition and contributes to a healthy ecosystem.