What are Cover Crops?
Cover crops refer to any plant population established to benefit the soil, whether in rotation with cash crops or between rows of orchards or vines. The main purpose is to protect and enrich soils, leading to better soil health over time. A cover crop is a crop planted primarily to manage soil fertility, soil quality, water, weeds, pests, diseases, biodiversity and wildlife in an agro ecosystem (Lu et al. 2000), an ecological system managed and largely shaped by humans across a range of intensities to produce food, feed or fibre.
Cover crops are of interest in sustainable agriculture as most of them improve the sustainability of agro ecosystem attributes and may also indirectly improve qualities of neighbouring natural ecosystems. Farmers choose to grow and manage specific cover crop types based on their own needs and goals, influenced by the biological, environmental, social, cultural, and economic factors of the food system in which farmers operate (Snapp et al. 2005).
Cover Crop Selection
It is important to select the correct species and varieties to ensure the best results. There are many species and varieties available, therefore it is extremely important to contact a cover crop specialist to assist you with the selection process. When selecting cover crops, the following factors should be considered: your climate, soil type, goals and challenges.
A diverse mixture of cover crops provides a balanced diet for microbes through a unique process where plant species exudate chemical compounds through its roots. A greater diversity of plants leads to a greater diversity of microbes and a more robust soil ecosystem. For this reason, Barenbrug has more than 80 different cover crop species and more than 140 varieties available to help create this robust soil ecosystem!
The leaf area index (LAI) of diverse cover crop mixtures are normally higher due to better utilization of space with different growth habits. This leads to more photosynthetic products being transported into the soil, therefore accommodating more microbes compared to monoculture cover crops. This also benefits mycorrhizal fungi seeing that it cannot feed itself and depends on plants for carbon/sugar. Mycorrhizal fungi are very efficient at finding minerals that will help plants in return.
Some of the main soil health benefits that cover crops can provide:
- Organic Carbon
- Microbial activity
- Aeration and infiltration
- Nitrogen Fixation
- Weed suppression
- Erosion prevention
- Building soil structure
- Water conservation
- Combatting soil disease
Cover Crops Grown in Orchards and Vineyards
Cover crops have been grown between other crops for quite a while. These crops include vineyards, fruit trees, nut trees, vegetables, herbs, etc. Cover crops in vineyards and orchards can stabilize the soil structure, improve water infiltration, suppress weeds, reduce compaction and produce a mat of mulch that reduce evaporation. With all of these benefits it would be senseless to farm with ‘‘naked’’ soil where undesired plants are mechanically or chemically maintained.
Cover crops can be used as a sustainable solution to many of our challenges and can be seen as a practice that will ensure that our agricultural land will be preserved for our descendants. However, it is important to remember that cover crops are not a quick solution to all our problems. Planning is important and it may take time to get the expected result. Since cover crops have different functions, it is important to determine what the crop is expected to do. Is the intent to add organic matter to the soil? Perhaps to add nitrogen to the cropping system? To stimulate soil biological activity? Or to protect the soil during the winter months?
For more information please download our new cover crop guide or contact one of our agronomists.