Author: Stiaan Heyns
Editor: Suné Bartman
(MSc Agric Production Physiology and Product Quality)

In the previous article, we focused on the importance of regenerative agriculture, specifically cover crops, in promoting healthy soils and sustainable crop production. It discusses the potential benefits of cover crops, including the presence of beneficial insects and the reduced risk of crop diseases. It also emphasizes the importance of applying basic principles by applying specific practices, such as diversifying plant species, minimizing aggressive tillage and careful planning and management of crops. Cover crops are an important aspect for growers to consider, and the first thing they should do is determine a clear purpose for its use. Growers should determine what they want to get out of the cover crop in terms of benefits, such as: 

Other core benefits to remember about cover crops:

Cover crops increase root mass in different soil layers, leading to better aeration in the soil, as well as the soil’s water filtration and holding capacity. Cover crops aid in the rapid build-up of humus or organic carbon levels and improve microbial dispersal. It provides better protection against pests and for healthier soil as well as promoting favorable conditions for useful insects such as earthworms. It is important to keep all of these goals in mind when choosing cover crops or mixes. Depending on the specific needs of your farming operation, you can prioritize one or more of these goals.

 

For example, if you are primarily concerned with erosion control, you may want to choose cover crops with deep, fibrous root systems that can hold the soil. If nitrogen fixation is a priority, leguminosas cover crops may be the best choice. It is also worth considering how multiple goals can be achieved with a single cover crop or mixture, such as using Leguminosae for both nitrogen fixation and weed suppression. Producers should examine the available species of mulch crops to determine which species will best meet their needs. This can include selecting species that will grow best in the specific climate and soil type of the farm. When growers have a holistic approach to cover crops, they can optimize the management of the cover crops in their farming operations. This may include choosing when to plant, harvest and remove it. The correct management of cover crops can contribute to a healthy and sustainable farming operation catering to future generations. 

 

Since cover crops have different functions, it is important to determine what the purpose of the crop is. 

Its main purpose is to suppress weeds in a natural way.

Various cover crops are considered “smother” crops because they are used to control or suppress weeds. Crops that give the best results are those that germinate quickly, provide fast ground cover, and form dense leaf canopy. 

 

Its main purpose is soil improvement through nitrogen fixing. Legumes such as lupins, clovers, vetches, and beans that can capture atmospheric nitrogen can also provide nitrogen to subsequent crops. When sources of manure or compost are not readily available, legumes can be inserted in a crop rotation to supply nitrogen to the cash crops. Nitrogen fixation legumes should be inoculated with rhizobium bacteria before planting (see inoculation guidelines). Legumes require specific strains of fresh or well-preserved inoculants. Inoculation is especially important if the legume has never been cultivated on the site before. Also note that legumes have different growth habits, especially when they are used in mixtures. Some are crawlers and others have a recumbent growth habit. 

 

To interrupt pest life cycles, it is important to select cover crops from a different family than the future cash crops so that they do not harbor pests or diseases that can have a negative impact on the next cash crops. Some cover crops may carry out bio fumigation if tilled into the soil, while other crops serve as non-hosts. The host status differs between species and varieties for different pathogens and diseases.

 

The properties of the cover crop residue are very important because they have a direct influence on the outcome of organic matter decomposition (humification and mineralization) and other plant nutrition dynamics. Young and succulent green manor crops with a low C:N ratio will feed soil microorganisms, while a mature, fibrous green manure crop such as grain straw will form stable organic matter but provide less stimulation of soil biological activity.

 

The right cover crop can even look decorative among other ornamental plants. Crimson clover can serve as a good example, with its flowers tightly packed together like strawberry stems. You would hardly think that it improves the soil. Cover crops with large tap roots or bulbs can penetrate the soil and break compacted layers. In the process, it can increase filtration and aeration. It is not limited to these species, because all root types can support this process.

 

Faba beans tolerate water leached conditions better than other grain legumes such as field peas and lupins. This means that faba beans can grow better in soil that contains a lot of water or where there is a high groundwater mirror, unlike other legumes that cannot perform as well against water leached conditions and be resistant. Other options for crops that grow better in these conditions exclude field peas and lupins, but there are other options that can be considered.

 

Cover crops can play an important role in promoting biodiversity and ecosystem services in farming systems. By attracting beneficial organisms such as predator insects, parasitoids, and pollinators, cover crops can help control pests and increase crop yields, for example,“Buckwheat” is a cover crop known for attracting a wide variety of beneficial insects, including lacewings, ladybugs, and hoverflies, all of which are natural hunters of louse, thrips, and other crop pests. Phacelia is another cover crop that is attractive to pollinators, such as bees, and also provides habitat for beneficial insects.

 

Radish and mustard plants are also effective cover crops in attracting beneficial organisms. Radish can attract soil beetles, which are predators of slugs and other ground wound pests, while mustard plants can attract parasitic wasps that lay their eggs in the eggs or larvae of other insects, eventually leading to their death. Overall, cover crops can be a valuable tool in promoting natural pest control and increasing biodiversity in farming systems. By providing habitat and food for beneficial organisms, cover crops can help reduce reliance on synthetic pesticides and fertilizers and promote a more sustainable approach to agriculture.

 

In this article, we put the focus on winter cover crops . There is a large selection of winter cover crops to choose from and the choice depends on the specific conditions of your farm. For example, if you have a drought-stricken area, you might consider choosing crops that can grow well in low rainfall conditions. If you have problems with weeds, you can choose crops that grow quickly and form a thick crop. The most common winter cover crops include oats, rye, vetch, triticale, lupins, medics, clovers, various varieties of cabbage and many more. It is important to remember that a good plan for winter cover crops often includes a combination of several crops in order to achieve a wide variety of goals. 

Winter cover crops are planted in the autumn and winter months to cover the soil and protect it from erosion, washing out and evaporation during winter and early spring. These crops can also help make the soil healthier by adding organic matter to the soil, improving the structure of the soil, and increasing the biodiversity in the soil stage. An important aspect of winter cover crops is that they can also serve as a source of food for livestock and wildlife during winter. It can be in the form of pasture, hay or silage. Some of these crops may also play an important role in managing weeds, improving soil fertility and promoting biological control of pests. 

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Winter Cover Crops 

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