Crop rotation is an ancient farming practice that has been used by farmers since the BC century. Crop rotation is 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 at all 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 very early years, farmers used to practice crop rotation, but they had no idea of the scientific reasons behind the success of the practice, nor did they have a specific term for the practice. 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
- 1. Increases Soil Fertility
- 2. Increases Crop Yield
- 3. Increases Soil Nutrients
- 4. Reduces Soil Erosion
- 5. Limits the Concentration of Pests and Diseases
- 6. Reduces the Stress of Weeds
- 7. Improves the Soil Structure
- 8. Reduces Pollution
- 9. Diversification and Reduced Cost of Production
- 10. The Nutrient Uptake Regulation
- Disadvantages of Crop Rotation
- Various Types of Crop Rotation
- How to Select the Right Crops for the Rotation?
- Categories of Vegetables based on their Nutrient Requirements
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 nutrient interaction with the soil, and each of them 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 that are not available or absorbs nutrients that are in abundance.
It also increases and improves the soil organic matter caused by the micro-organisms left behind by each type of crop planted. Animals that also graze on land left to fallow contribute to adding manure to the ground that fertilizes the soil. 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, therefore, 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 advantage of crop rotation. Notably, the practice has been seen to be successful in increasing the fertility of the land over a period of time.
3. Increases Soil Nutrients
As earlier stated, crop rotation allows the land to regenerate and rejuvenate its own nutrients without having to apply more nutrients through the use of 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.
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. Each crop type adds up to or absorbs different soil nutrients from the soil; therefore, it needs a mix-up of a variety of 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 by wind or water. 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 the 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 pathogens; therefore, crop rotation interrupts the pest life cycle and their habitat. A cycle entails similar events that happen in constant rotation, meaning that the infestation of pests and diseases happens in the season. Farmers can see a decrease in the incidence of insect pests and pathogens when they try crop rotation.
As a farmer, when you are aware of 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. This, in the long run, allows the farmer not to use tillage on the ground as it is a harmful technique of weed management to the soil structure.
7. Improves the Soil Structure
Crop rotation helps prevent soil compaction, thus improving the physical condition of the soil. Crop rotation improves the soil structure as well as the soil texture. This allows for good conditions for seed germination and root proliferation.
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 in the soil 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, and it prevents the accumulation of toxic chemicals or substances secreted by some crop plants.
Thus, it allows the farmer to plant crops successfully without the need to apply fertilizers.
Crop rotation also reduces the constant infestation of crops by pests and diseases, stopping the need to spray crops with pesticides. Although pesticides work very well on crops, they 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 cost of production of the crops decreases 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 helps in increasing the nutrient uptake of the plants from the soil, as in crop rotation, different crops require different nutrients in different 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
1. It Involves Risk
In crop rotation, investing in a season involves the input of a lot of money to buy different seedlings of the different types of crops to be planted.
Moreover, certain crops need specific kinds of equipment, so farmers may have to invest in different types of machinery. This means the initial costs can be higher. The success, however, for each crop type is not guaranteed, and one can end up incurring a loss of harvest.
In addition, pests and diseases from other crops can spread and infect more crops. There is also the risk of a certain crop yield not being successful, and if that was the only crop type grown, there will be no yields for that planting season, and the farmer will have 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 of crop rotation, there is no need to experiment because there can be nutrient buildup that will take a longer time to correct. 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.
Improper implementation, hence, makes the farmer incur very great losses. Still, information about the different planting techniques is easily available, and the farmer should be vigilant as well as ready to practice them as required.
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 type of crop. The farmer is not able to produce a single crop on a large scale over a long period of time 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 requires different types of machinery, and operating them also requires knowledge. This means farmers will have to 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
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 the planting of maize and then mustard. 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 for two years, and more crop selections are available.
For a two-year crop rotation, there could be two, three, or four crops to be planted within the whole duration of the rotation. The successive crops should have their nutrient requirements attained after the harvest of the prior crop.
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 all the nutrient requirements of each crop.
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 the planting of rice, wheat, mung, and mustard successively; sugarcane and berseem successively; and the planting of 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
1. Leaf Crops
Leaf crops are those that need way more nutrients than the other vegetable categories. Leaf crops include cabbages, broccoli, kales, spinach, cauliflowers and 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 and 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 and 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, and etc.
Cereals include maize, sorghum, millets, wheat, rice, barley, oats, rye, and etc.
Minor farmers usually grow vegetables from the different categories mentioned above, in relation to their nutrient requirements. They usually start with the highest nutrient-maintained crops and work their way down the least nutrient-maintained crops. Through the proper order of planting crops, the crop rotation of the farmers would be successful.