|The Use of Cover Crops in Vineyards and Its Benefits
Erosion, soil deterioration due to excessive farming and tillage, biodiversity loss, and loss of water and moisture from topsoil are just some of the difficulties modern farmers face in all cropping systems, including vineyards.
Cover crops could be a potential solution to these issues. Although the use of cover crops is as old as winemaking itself, it is still being determined whether cover crops are superior to standard soil management techniques, even though this strategy has demonstrated advantages. Traditional procedures such as tillage, which require machinery and tractors, compact the topsoil to a depth of approximately 15 centimeters, making it less porous. Additionally, vineyards planted on sloped terrain are highly susceptible to soil erosion.
Cover crop cultivation in vineyards is not new, but it is gaining popularity, especially in organic vineyards. They should be planted between the vine rows and sometimes under the vines five or six years after the vineyard has been produced.
The selected civilizations may vary from year to year. It depends on our objectives. Crops must be capable of forming solid grass and have root systems that can bind the soil.
Cover crops have multiple roles and benefits. Some of them are the:
- positive impact on biodiversity in the soil
- improvement of the organic content in the soil that leads to a better aggregate structure of the soil
- reduction of the negative impact of compacted soil due to agricultural machinery
- erosion control: by covering the soil surface, they are effective at reducing raindrop impact and slowing surface water movement, which can be particularly problematic on sloped terrain
- enhancement of water absorption and air capacity
- preservation of the moisture by leaving a ”carpet” that is left on the surface after mulching
- help with low-temperature resistance
- facilitate the movement of machines through the rows (the soil is less muddy)
Hence, this wine-growing technique can enhance soil quality and prevent soil deterioration.
Cover crops, like everything else in agriculture, can have negative consequences. For instance, they may provide ideal circumstances for rodents and other pests, serve as hosts for particular illnesses, or threaten the availability of nutrients and water.
To prevent crops from competing with vines for water and nutrients, we must select and apply them with care and prudence. Catch rotation is recommended to combat pests and pathogens and prevent and control diseases in the vineyard.
Grasses (barley, wheat, oat, rye, etc.):
- useful for erosion control
- fast growing
- easily managed residue
- accumulate soil nitrogen in symbiosis with Azospirillum but not able to fix nitrogen from the atmosphere
Legumes (fava beans, cowpeas, clovers, alfalfa, etc.):
- nitrogen-fixing plants
- more extensive root systems help maintain the soil structure
Broadleaf non-legumes (radishes, mustard, etc.):
- absorb soil nitrogen
- holds the soil in place (protects from soil erosion)
- can be used for green manure
Depending on the local environmental conditions (soil pH, nitrogen and water availability, salinity, shade, temperatures, etc) the farmer may choose to apply some of the above mentioned species in mixes (e.g., legumes and grasses). The ratio of each part may vary.
We have a few alternatives when employing cover crops in our vineyards, but they essentially boil down to tilling or not tilling the soil.
Under the tilling method, cover crops (barley, wheat, and winter peas) are sown annually and grown from October through spring before being tilled. This method requires tilling, which might disturb the topsoil and expose it to the sun during periods of extreme heat.
If winegrowers wish to wait until their soil, they have a few options, including mowing or mulching the cover crop and leaving it on the surface. These choices include:
Self-reproducing plant varieties (some clovers and grasses)
Annually sown plants (barley, wheat, broad beans), perennial plants, or indigenous grasses (alfalfa, red clover)
Farmers frequently use a method in which cover crops are planted every other row so that one row is tilled and the other is not. The rows can then be rotated annually or every few years.
Vineyard-specific species (or seed mixtures) should be used for this application. It relies on several variables, including soil type, slope, microclimatic conditions, and the winemaker's intentions.
Under warm, humid, and moderate Mediterranean conditions, one study revealed that a cover crop with 50 percent clovers might release up to 30 kg/ha of fixed nitrogen. Choosing this seed mixture on nitrogen-rich soil would be a poor decision.
The study done in La Rioja (Spain) on the Tempranillo grape variety was to assess the effect of barley and clover cover crops on the nutritional status and availability of N, P, K, and Mg in grapevines. Cover crops had little effect on P, K, or Mg uptake. Barley lowered nitrogen availability after one year as a cover crop, whereas clover enhanced nitrogen availability after two years.
Five years after the introduction of cover crops, another study in La Rioja revealed increased organic carbon, water-soluble carbon, and potentially mineralizable nitrogen.
In southern Italy, researchers evaluated the impacts of Fescue (Festuca arundinacea) cover crop and conventional tillage throughout three growing seasons. The results demonstrated that cover crops enhanced soil organic carbon, total nitrogen, and microbial biomass but did not affect grape quality and yield.
Before seeding the chosen plants, it is essential to prepare the soil. This preparation should be carried out under conditions of moderate humidity. It is suggested that the surface be well-leveled and lightly compacted so the seeds can reach a depth of 0.5 to 2.5 centimeters.
Planting can occur in late summer, autumn, or early spring. It is unnecessary to fertilize the cover crop because the vineyard should be fertilized beforehand. When spraying herbicides on undesirable plants (such as under the vines), farmers must be aware of the possibility of a drift toward the crops. After mowing, the weight of the mass might severely affect the remaining yield, so mowing should occur before the crop grows too much and forms a large group.
One can mow or till crops. Tilling is performed in the spring when there is still sufficient moisture in the soil. Before tilling, cultivators typically trim the crop to aid in the decomposition of plant leftovers. If only mowing is selected for crop maintenance, it can be performed in the spring or late spring/summer. Spring mowing limits the amount of shade caused by weed species, and cover crops are kept from growing too tall in late spring. In both instances, the mowed residue can prevent soil moisture loss during the dry summer months.
- Mirosevic, N., Karoglan-Kontic, J. (2008.). Vinogradarstvo
- Eva P.Pérez-Álvarez, Enrique García-Escudero, Fernando Peregrina (2015). Soil Nutrient Availability under Cover Crops: Effects on Vines, Must, and Wine in a Tempranillo Vineyard. American Journal of Enology and Viticulture
- Eva P.Pérez-Álvarez, Mikel Colina, Enrique García-Escudero (2012.). Cover crops and tillage influence soil organic matter and nitrogen availability in a semi-arid vineyard. Agronomy and soil science
- Concetta Eliana Gattullo, Giuseppe Natale Mezzapesa, Anna Maria Stellacci, Giuseppe Ferrara, Giuliana Occhiogrosso, Giuseppe Petrelli , Mirko Castellini, Matteo Spagnuolo (2020.). Cover Crop for a Sustainable Viticulture: Effects on Soil Properties and Table Grape Production. Agronomy