Crop rotation is an ancient farming practice used by farmers since the BC century. It’s defined as the intentional planting of different types of crops in different parts of the field and at different seasons sequentially. It also entails choosing not to plant anything in a given season and allowing the land to rejuvenate while bare until the next season.
In crop rotation, one can also incorporate livestock into the practice when the land is left bare for a season of grazing.
In the early years, farmers practiced crop rotation, but they had no idea of the scientific reasons behind the practice’s success or even a specific term for it. This means they did not even know its impact on the environment.
Typically, they did it because of the seasonal calendar of the planting of crops, which was set traditionally as a planting pattern. Here are some of the known advantages and disadvantages of crop rotation.
Advantages of Crop Rotation
There are many benefits to crop rotation, according to agriculturists and agronomists. It helps in increasing soil fertility along with crop productivity. Let’s discuss some of them in this section.
1. Increases Soil Fertility
Prolonged planting of the same crop type leads to the depletion of specific nutrients in the soil. Each crop type has a different nutritional interaction with the soil, and each releases and absorbs different types of nutrients.
Because of this, crop rotation increases soil fertility by controlling deficient or excess nutrients because it replenishes nutrients not available or absorbs nutrients that are in abundance.
It also increases and improves soil organic matter caused by the micro-organisms left behind by each crop planted.
But that’s not all — animals deployed during grazing seasons contribute by adding manure to the ground that fertilizes the soil. Plus, biomass left behind when harvesting also improves the fertility of the soil as it is purely green manure.
2. Increases Crop Yield
Crop rotation increases the harvest obtained from a single seasonal harvest. Because of the incorporation of different crop types, one gets not only a variety of crops after each season but also a general bounty harvest. Some scientific evidence proves a 10 to 25% increase in crop yield in crop rotation rather than monoculture.
The availability of nutrients from the soil provides abundant nourishment to all plants, ensuring success in the yield produced.
Most farmers are advised to practice crop rotation when the land becomes still and does not produce as much as it should, further demonstrating the practice. Notably, crop rotation has been seen to be successful in increasing the fertility of the land over a period of time.
3. Increases Soil Nutrients
As stated earlier, crop rotation allows the land to regenerate and rejuvenate its nutrients without fertilizers. Leaving the land bare for a season enables the land to restore the soil nutrients lost through absorption by plants harvested in the previous season.
Moreover, by planting crops like legumes, for example, one can increase nitrogen in the soil as they contain nitrogen-fixing bacteria that fix nitrogen naturally into the soil.
Basically, each crop type adds up to or absorbs different soil nutrients from the soil. Therefore, it needs a mix-up of various plants to make them more balanced.
Knowing what plants to grow after a rotation is critical to avoiding either excessive nutrient buildup or excessive nutrient absorption from the soil.
4. Reduces Soil Erosion
Soil erosion is the carrying away of the most important topsoil layer, either by wind or water. But when the soil is constantly covered by plants, the topsoil layer is not carried away by water during heavy rainfall.
A layer of crawling plants or cover crops like beans and peas works well to prevent erosion by giving the ground full crop cover, unlike standalone crops like maize, which leave land exposed to soil erosion elements.
Crop rotation also helps reduce raindrop impact on the soil and general erosion by water because the roots of the plants hold the top layer of soil together. Trees planted together with crops on the farms also assist in preventing soil erosion.
5. Limits the Concentration of Pests and Diseases
Similar plants tend to have the same diseases. However, crop rotation interrupts the pest life cycle and their habitat.
Monoculture entails similar events in constant rotation, meaning that the pests and diseases associated with the cultivated crop can only keep increasing. However, with crop rotation, farmers can see a decrease in the incidence of insect pests and diseases.
Plus, as a farmer, when you know the kinds of pests and diseases that break out at a given time of the year and the crops affected, you can plant the host plant at a different season when the chances of infestation are low.
This lowers the risk of plants getting infested and allows the farmer to grow crops each season without using pesticides, which is good for the environment.
6. Reduces the Stress of Weeds
Crop rotation is a traditional weed control method that also helps in the weed-free cultivation of crops. It involves maintaining field conditions such that weeds are less likely to grow and/or increase in number. In other words, crop rotation allows the crops to crowd out weeds during the competition for nutrients and other resources.
Weeds are a constant nuisance to any farmer, and control can be done through tillage or mowing. They are a major enemy to crops as they bring competition for nutrients.
Crop rotation thus reduces the population of weeds or, better yet, denies them an opportunity to grow. In the long run, this allows the farmer not to use tillage on the ground as it is a harmful weed management technique to the soil structure.
7. Improves the Soil Structure
Crop rotation helps prevent soil compaction, thus improving the physical condition of the soil. The practice improves the soil structure and texture, allowing for good seed germination and root proliferation conditions.
It also helps with other soil processes, such as water infiltration and aeration, which have a lot of benefits for the crops and improve the composition of the soil.
However, it all depends on the type of crops being rotated, such as cover crops that reduce the spread of weeds, thereby reducing tillage that damages the soil structure.
An important element in the soil structure is the pores. With large pores in the soil, water easily drains, while small pores do not allow for proper air and water circulation. Crop rotation generally helps to improve the soil structure.
8. Reduces Pollution
The constant application of fertilizers to soils causes soil leaching, which is the excessive buildup of nutrients in the soil to a toxic and harmful level that does not allow plants to grow well. Crop rotation increases the nutrients in the soil, preventing the accumulation of toxic chemicals or substances secreted by some crop plants.
Thus, it allows the farmer to plant crops successfully without applying fertilizers.
Crop rotation also reduces the constant infestation of crops by pests and diseases. This stops the need to spray crops with pesticides, which, although they work very well on crops, contain dangerous chemicals that can build up in the soil to harmful levels.
9. Diversification and Reduced Cost of Production
The cultivation of certain crops requires less labor and machinery compared to others. It helps to distribute the workload and resources used throughout the year, for which the crop production costs decrease to a certain extent.
This mostly depends on the type of crop we select. Furthermore, farmers are given more options for selling different products and are no longer reliant on a single crop and market price.
10. The Nutrient Uptake Regulation
Crop rotation increases the nutrient uptake of the plants from the soil since the different crops require diverse nutrients in varying quantities.
Through crop rotation, the different crops being planted within the rotation maximize all the nutrients in the soil, including the leftover nutrients from the prior crop planted. One after the other, the nutrient requirements of each crop are being met and sustained through crop rotation.
Disadvantages of Crop Rotation
Despite the numerous advantages of crop rotation, it’s still worth noting that this practice has its fair share of disadvantages. Here are some of the drawbacks to crop rotation:
1. It Involves Risk
In crop rotation, investing in a season involves a lot of money to buy different seedlings of the different types of crops to be planted.
Moreover, certain crops need specific equipment, so farmers may have to invest in different types of machinery. This means the initial costs can be higher. However, success for each crop type is not guaranteed, and one can lose harvest.
Moreover, pests and diseases can easily move from one crop to another, causing widespread infections. There’s also the danger of a particular crop failing to yield successfully. If that’s the sole crop grown, there won’t be any harvest for that planting season, and the farmer will need to wait for the next season.
2. Improper Implementation Can Cause Much More Harm Than Good
Improper implementation of this technique causes much more harm than good. If one lacks the technical know-how, there is no need to experiment with it. Otherwise, it can result in nutrient buildup that will take longer to correct.
Ideally, one has to have the skills to know what crops can be planted after the other and in which season for the process to be successful.
Incorrect execution can lead to significant losses for the farmer. However, there’s ample information about diverse planting techniques readily accessible. Farmers must stay attentive and adopt these practices diligently when needed.
3. Obligatory Crop Diversification
For crop rotation to work, one has to plant different crops every time. Nonetheless, it does not allow a farmer to specialize in a single crop type. The farmer cannot produce a single crop on a large scale over a long period because of the damage it will do to the soil.
The practice of crop rotation is necessary to improve yields. Crop diversification also requires investment in different planting techniques for each unique crop; that costs time and money because each crop needs a different type of attention.
4. Requires More Knowledge and Skills
Crop rotation means a variety of crops; therefore, it requires a deeper set of skills and knowledge regarding each type of crop harvested. It also necessitates working with different types of machinery, and operating them also requires knowledge. Hence, farmers must invest more time and resources in learning and mastering this agricultural practice.
5. The Difference in Growing conditions
Certain locations and their climates are more favorable for monoculture, meaning a certain kind of crop. Other crops, other than that specific type of crop, cannot grow well in that specific type of temperature and soil conditions.
Various Types of Crop Rotation
Having looked at the pros and cons of crop rotation, let’s now delve into the various types of the practice.
1. One Year Rotation
Depending on the piece of land available, crop rotation can be done for one year. One type of crop would be planted for half of the year, and after the harvest, the soil remaining that fits the needs of another certain crop will be planted with the other crop for the rest of the year.
An example of a one-year crop rotation is planting maize and then mustard after you’ve harvested the corn. Another example is the planting of rice and then wheat.
2. Two Years Rotation
The two-year rotation is pretty much the same as the one-year rotation except that the duration of the rotation of crop planting would be two years, and more crop selections are available.
In a two-year crop rotation, two, three, or four crops can be planted during the entire rotation period. Each following crop should receive the necessary nutrients after the previous crop’s harvest.
Examples of a two-year rotation include the planting of maize, mustard, sugarcane, and fenugreek successively, as well as the planting of maize, potato, sugarcane, and peas successively.
3. Three Years Rotation
By its name, a three-year rotation involves a series of crops to be planted within a three-year duration while meeting each crop’s nutrient requirements.
The crops will be planted successively, one after the other, on the same land. With the other prior crops planted, the nutrient requirements of the next crop to be planted will be met.
Examples of a three-year crop rotation include planting rice, wheat, mung, and mustard successively; sugarcane and berseem successively; and planting cotton, oat, sugarcane, peas, maize, and wheat successively.
How to Select the Right Crops for the Rotation?
- Check what will be the source of moisture. Is it either rain or irrigation?
- Check the status of the nutrients in the soil. Take consideration of the nutrient content of the soil after each harvest.
- Check the availability of inputs, like fertilizers, pesticides, machine power, and manpower.
- Check if the crop is being planted for a short or long duration.
- Check the marketing and processing facilities if necessary.
- Rotate by plant part harvested.
- Rotate by plant family.
- Rotate by plant compatibility.
- Rotate by nutrient requirements.
- Rotate by rooting depth and type.
- Include legumes and cover crops.
Categories of Vegetables based on their Nutrient Requirements
Some of these categories include:
1. Leaf Crops
Leaf crops are those that need way more nutrients than the other vegetable categories. They include cabbages, broccoli, kale, spinach, cauliflower, etc.
2. Fruit Crops
Fruit crops need a considerable amount of nutrients but not as much as the nutrient requirements of leaf crops. Fruit crops include eggplants, peppers, tomatoes, chilly, etc.
3. Root Crops
Root crops need less nutrients than both leaf and fruit crops. Their nutrient requirements are not as high as the other two, making it easier to find land areas to plant them. Root crops include potatoes, beetroots, carrots, onions, radishes, turnips, etc.
Legumes are usually planted after all of the necessary crops within a rotation. Their purpose is to fix nitrogen from the atmosphere into the soil. Legumes are beneficial crops, not only as a food source but also for the soil condition. Legumes include chickpeas, cowpeas, beans, pigeon peas, grams, etc.
Cereals include maize, sorghum, millet, wheat, rice, barley, oats, rye, etc.
Minor farmers usually grow vegetables from the categories mentioned above concerning their nutrient requirements. They usually start with the highest nutrient-maintained crops and work their way down to the least nutrient-maintained crops. Through the proper order of planting crops, the crop rotation of the farmers would be successful.