Crop rotation is the planned successional growth of various crops on a given plot of land. Simple crop rotations may consist of two or three crops, while complicated crop rotations may contain a dozen or more crops. Without using artificial inputs, crop rotation assists in replenishing soil nutrients. Additionally, this practice breaks the cycles of pests and diseases, boosts soil health by increasing biomass from various crops' root systems and boosts biodiversity on the farm. This article will explain to you about Crop Rotation which will be helpful in preparing the Agriculture Syllabus for the UPSC Civil Service exam.

Typical Cycle of Crop Rotation

Criteria for Selection of Crops for Rotation

• There should be enough moisture.
• Fertilizer, labour, and machine power are all available.
• Marketing and processing facilities.
• Nutrient availability in the soil.
• The crop's duration—short or long.

What is the need of Crop Rotation?

• Different plants have different nutritional requirements and are vulnerable to various pathogens and pests.
• If a farmer plants the same crop in the same spot every year, as is common in conventional farming, the same nutrients are drawn out of the soil year after year.
• Pests and diseases will happily make themselves at home as long as their preferred food source is available.
• Increased levels of chemical fertilisers and pesticides are required in monocultures like these to keep yields high while keeping bugs and disease at bay.
• Crop rotation aids in the return of nutrients to the soil without the use of synthetic fertilisers.
• Additionally, the practise works to interrupt pest and disease cycles, improve soil health by increasing biomass from different crop root structures, and increase farm biodiversity.
• Variety is essential for soil life, and beneficial insects and pollinators are drawn to it above ground as well.

Crop Rotation - Principles

• Due to fact that legumes fix atmospheric nitrogen into the soil and add organic matter to the soil, they should be planted before non-leguminous crops.
• Crops with tap roots (deep rooted crops like cotton) should be followed by crops with fibrous roots (shallow rooted crops like sorghum or maize). This allows for the proper and uniform use of soil nutrients.
• More exhaustive crops should be followed by less exhaustive crops because crops such as potato, sugarcane, maize, and others require more inputs such as better tillage, more fertilisers, more irrigation, and so on.
• Crop selection should be based on need or demand.
• Crops from the same family should not be grown consecutively because they serve as alternate hosts for insect pests and diseases.
• Crop selection should take into account the farmer's financial situation.
• The crop chosen should also be appropriate for the soil and climatic conditions.

*For detailed notes of this topic, check this link Principles of Crop Rotation

Crop Rotation - Planning

• Divide the crops into families when planning a rotation. This adheres to the principle of not cultivating the same crop or one from the same family.
  • For example, beets, chard, and spinach are all members of the same family.
• Consider how much space the crop will require. Radish requires far less water than corn.
• Many farmers rotate their livestock among different pasture sections in addition to rotating crops. This improves manure dispersal in the fields and prevents overgrazing in any one section.
  • Overgrazing of pasture can result in vegetation depletion and soil erosion.
• Planning an effective rotation necessitates weighing fixed and fluctuating production circumstances such as market, farm size, labour supply, climate, soil type, growing practises, etc.
• Furthermore, crop rotation must consider how one crop will leave the soil for the succeeding crop and how one crop can be seeded with another crop.
• A nitrogen-fixing crop, such as a legume, should always come before a nitrogen-depleting crop; similarly, a low residue crop (i.e. a crop with low biomass) should be offset by a high biomass cover crop, such as a mixture of grasses and legumes.
• There are no restrictions on the number of crops that can be used in a rotation or the length of time it takes to complete a rotation.
• Rotation decisions are made years in advance, seasons in advance, or even at the last minute when an opportunity to increase profits or soil quality arises.

Crop Rotation - Types

One-year Rotation

• Crop rotation can be carried out for one year, depending on the size of the available plot of land.
• Following harvest, the soil that is suitable for another specific crop will be planted with that crop for the remaining half of the year. One crop would be planted during the first half of the year.
• The planting of maize and then mustard is an example of a one-year crop rotation.
• Another example is the planting of wheat first, then rice.

Two Years Rotation

• The two-year rotation is essentially identical to the one-year rotation, with the exception that more crop options are available and the crop planting rotation would last for two years instead of one.
• Within the course of a two-year crop rotation, there may be a total of two, three, or four crops planted.
• After the prior crop is harvested, the subsequent crops should have all of the nutrients they need.
• A two-year rotation might involve planting successive crops of corn, mustard, sugarcane, and fenugreek as well as subsequent crops of corn, potatoes, sugarcane, and peas.

Three Years Rotation

• A three-year rotation, as the name suggests, calls for a number of crops to be planted over the course of three years while addressing all of their nutrient needs.
• On the same piece of land, the crops will be planted one after the other in succession.
• The subsequent crop's nutritional needs will be satisfied by the previously planted crops.
• Some examples of three-year crop rotations include:
  • Rice, wheat, mung, and mustard in succession;
  • Sugarcane and berseem in succession; and
  • Cotton, oat, sugarcane, peas, maize, and wheat in succession.

Crop Rotation - Advantages

• Improves Soil Condition: Utilizing various crops, especially those with fibrous or tap roots, can improve the soil's chemical, biological, and physical composition. This increases the amount of organic matter and nutrients in the soil as well as its ability to store water.
• Improves Soil Structure: Rotation helps to preserve and improve soil structure. Crops have various root structures and grow to different depths. Rotating exposes the soil not only to shallow depth crops, but also to deep diggers, which gradually deepen the topsoil.
• Reduces Soil Erosion and Water Runoff: Crop rotation can reduce erosion by enhancing the microbial populations and soil tilth. Surface runoff is reduced as a result of the more stable soil structure created.
• Reduces Pests and Weeds: Pests, plants, and insects can't live without their host for very long. Those pests have no chance if you move your crops around and improve the soil structure at the same time.
• Control of Insects: Insects tend to enter your plants' leaves and vines as they prepare to reawaken in the spring in search of their favourite meal. When you rotate, these insects come into contact with a plant that they do not feed on.
• Disease Prevention: Plant diseases can over winter enter in plant leaves, roots, and vines beneath your soil. Crop rotation helps to keep these diseases from returning the following year.
• Improvement in Water Quality: Water quality can be improved by reducing sediment loss, as well as dissolved and sediment-attached nutrient and pesticide losses.
• Provides Diversification: Some crops demand less labor and equipment than others. This implies that the workload can be distributed throughout the year.
  • Additionally, it increases the range of the products that can be sold, preventing from having to "place all your eggs in one basket."
• Nutrient Uptake Regulation: As various crops require different nutrients in different quantities, crop rotation aids in boosting the nutrient uptake by plants from the soil.
  • Crop rotation helps the various crops that are planted within the rotation make the most of all the nutrients in the soil, including the nutrients left over from the previous crop that was planted.

Crop Rotation - Disadvantages

• Involves Risk: Crop rotation requires a significant financial investment each season to purchase various seedlings of the various crops that will be grown.
  • Moreover, particular crops demand specific sorts of equipment, thus farmers may have to invest in different types of machinery.
  • This implies that the upfront fees can be higher. However, the success of each crop kind is not assured, and one may wind up losing a harvest.
• Requires More Skill & Knowledge: Crop rotation calls for a broader range of abilities and information regarding each type of crop collected because it involves a variety of crops.
  • It also calls for various machinery, the operation of which also takes skill. This implies that learning and perfecting this agricultural method will require more time and effort on the part of farmers.
• Difference in Growing Conditions: For monoculture, or a particular type of crop, some places and their temperatures are better suited.
  • The specific type of temperature and soil conditions cannot support the growth of any other crops than that particular type of crop.
• Obligatory Crop Diversification: It is mandatory to plant different crops each time for crop rotation to be effective. However, it prevents a farmer from specializing in a particular crop.

Conclusion

Previously, not planting anything (also known as leaving the field fallow) allowed the land to rest and replenish its nutrients. Crop rotation has helped to increase productivity by replacing fallow periods with growing different crops that replenish soil nutrients. Crop rotation also aids in the fight against erosion forces. Rotating crops improves soil stability by alternating between crops with deep roots and those with shallow roots. Pests are also deterred by eliminating their food source on a regular basis. Crop rotation is affected by a variety of factors, including soil type, climate, precipitation, and crop markets.