The best harvest for a producer is the one that truly generates strong profit—profitability is more important than productivity at any cost. In Brazil, the agricultural calendar is one of the most dynamic; according to Conab, up to three crops can be grown in the same year. However, to achieve positive results, especially in soybean cultivation, the land needs to ‘rest’ for a period. This is known as fallow.
The practice of fallow dates back to early agricultural methods developed thousands of years ago. It helps prevent soil degradation, as planting of successive crops is paused for a certain period.
This ‘pause’ between harvests allows the soil’s biological structure to recover, enabling deeper root development and improving nutrient quality for future planting.
Some farmers who adopt fallow, for example, plant tree species along with a mix of regenerative plants — green cover — to enhance land regeneration. This increases mineral nutrient levels, reduces soil compaction, and decreases the presence of diseases and competing weeds through the effects of crop rotation.
Green roof
Before addressing the importance of cover crops in farming, it is necessary to understand which species are most commonly used in the interval between one harvest and another.
Among the most widely cultivated are oats, forage radish, ryegrass, vetch, crotalaria, mucuna, lupin, rye, millet, and wheat, among others.
It is important to note that each crop has an optimal planting time, which may occur in summer or winter depending on the farm’s location.
What are the benefits of using these plants in farming? According to Epagri, they include:
Erosion control: The presence of cover crops prevents soil erosion, acting as a protective layer that reduces the direct impact of raindrops on the soil.
Beneficial fauna: Organisms living on the soil surface and in its upper layers find shelter and food in cover crops, which also helps reduce pest and disease issues.
Organic matter: Improves soil structure, enhances moisture retention, and increases porosity, allowing better circulation of water and air.
Thermal insulation: Prevents direct sunlight from reaching the soil surface, reducing water evaporation.
Compaction: Acts as a buffer against the excessive weight of machinery, tractors, and animals, reducing the risk of surface soil compaction.
Role of roots: Increases soil porosity, facilitating water infiltration.
Nitrogen: Plants are the only natural agents capable of incorporating nitrogen into the soil.
Weed control: Cover crops reduce the germination potential of weed seeds.
Natural herbicide: During the decomposition of plant residues, organic compounds are released that inhibit the growth of weed species.
Pests and diseases: Cover crops are not affected by the same pests as commercial crops, helping to break the life cycle of these agents.
Biological pest control: For example, crotalaria can be used to control nematodes that affect crops such as soybeans, tobacco, and onions.
Caring for cover plants
To achieve good results during the off-season period, the sowing of these cover crops must be carefully planned to avoid setbacks. For example, the species should not exhibit seed dormancy, and proper management requires that they be eliminated before producing viable seeds.
They should also be easy to terminate. These precautions are necessary to ensure that these plants do not become undesirable or invasive.
When used as intercrops, it is important to consider the plants’ growth habits and vigor so that they do not compete for resources with the main crop or interfere with crop management practices.
In addition, the selected plants must be healthy and should not host pests or diseases that could negatively affect the agricultural crop.
