Cover crops, like the name suggests, are planted for the main purpose of covering the soil when it is barren between the growing seasons. Cover crops differ from cash crops since cash crops are grown to be either consumed or sold for profit.
Cover-crops are an integral part of a successful and sustainable farming practice with its wide array of benefits ranging from preventing soil-erosion, the addition of vital nutrients back into the soil, soil-microbes decomposition, increasing the yield of the main crop, or in some cases, to add as a supplement to the yield.
The importance of cover crops is increasingly being realized in conservational farming techniques where it is being integrated with no-tillage practices. However, it is very important to understand the concept of cover crops and species selection properly to make full use of this practice.
Which Type of cover crops to plant?
There are several things that you need to keep in mind before deciding on the type of cover crop to plant. Some of the things to consider include:
- The duration for which you intend to keep the cover.
- The intended killing method of the cover-crop after the cover duration.
- Season of plantation – winter or summer season.
- The food or cash crop you’ll be growing after the cover crop.
After carefully identifying the objectives of adding a cover crop in your crop rotation, you’ll then have a much clearer picture of the type as well as the specific cover crop that best fits your needs. The major types of cover crops you may choose are legumes, non-legumes, or a mix of all.
Legumes: Some of the common ones are peas, clovers, and vetch and their varieties. Legume cover crops are specifically used to increase the amount of nitrogen and nitrates in your soil. This helps to reduce the need for nitrogen-fertilizers later on in the food crops.
Non-legumes: Grasses are widely used to cover crops in the non-legume category along with cereals. Non-legumes serve a different purpose to that of legume cover crops in that they help to trap and retain the nutrients for the duration of the cover period while also providing physical integrity to the soil and reducing the effects of weeds. Moreover, when they are killed and laid out, the organic-matter content of the soil significantly increases.
Mixes: For serious farm-owners or small gardeners who wish to exploit all the good aspects of both types of cover crops, mixes of different types of cover crops may be the best option but it requires more cost and labor.
Benefits of cover crops
Cover-crop holds the potential of drastically increasing the productive potential of land either by enriching the fertility of the soil or by preventing it from degradation. Some of the benefits of cover crops include:
1. Preventing soil from being eroded: Since cover crops are called so because they cover the land when no other vegetation is present, the primary benefit of cover-crops is that in doing so, the soil is prevented from eroded due to the impacts of rainfall splash, flowing water or wind.
2. Maintenance of soil fertility: Cover-cropshelp maintain the soil fertility in several ways including acting as manure after the cover cycle, retaining the nutrients by preventing erosion and in the case of legumes, directly adding nitrates into the soil.
3. Management of weed, disease and pests: If lands are left barren during the fallow period, then there are high chances of weed invasion which will deplete the soil of its production potential. Even after being cut down and left on the land, cover crops form a protective layer above the soil which suppresses the invasion of weeds.
Similarly, cover crops are effective in the management of bacterial and fungal diseases by blocking the disease cycle. Finally, using cover crops to manage pests is mainly done by incorporating cover crop plants in the same time of plantation as that of food crops to attract pests towards the cover crop and away from food crops.
4. Water regime management: The addition of cover crops in your crop rotation helps to manage the soil moisture level throughout the year and helps to deal effectively with the unusual trend of rainfall and temperature levels observed throughout the world.
Besides these primary benefits, cover crops are also advantageous from an economic point of view since many of the cover crops like mustard also have a good commercial value.
Risks of planting cover crops
Since now we have established that cover crops are great ways of managing your farmland for increased yield, we must also learn about the potential risks as well as drawbacks of cover crops. The major drawback of a cover crop is that it adds costs to the entire operations. Moreover, the costs are usually made initially while the benefits are only accrued over a long period.
While cover-crops help to manage disease and pests, the opposite might also occur. They may further exacerbate the invasion and effect of diseases and pests if not applied correctly with the crop rotation time and the incorrect choice of species. For example, if a cover-crop plant is a host for a disease, it may act as a carrier of the disease which it transfers later to the food crop. Finally, some cover crops are also known to cause harmful allelopathic effects by the release of biochemicals to the cash crops.
Summary
Cover crops are effective means of achieving the desired outcome of sustainable and organic farmland management and crop production. But, proper research and understanding are required before making a decision on the type, method, and time of cover-crop addition to the crop cycle to make sure that the benefits outweigh the costs while also minimizing the associated risks.
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