Would you be willing to believe us if we told you that one simple practice can optimize soil nutrients, suppress weeds and control pests in your crops? You have to! Crop rotation is one of the cultivation practices that work miracles with crop productivity. Crop rotation is the cultivation of various crops in succession on a particular land in response to the ebb and flow of the seasons. Accordingly, the sequence of crops to be cultivated is designed to enhance soil health, improve soil nutrients, combat pests, and reduce weeds. In a simple rotation, two or three crops may be incorporated, however in a compound rotation, the number of crops may reach twelve or more. For example, rice-vegetable-legume is one of the recommended cropping patterns for a simple rotation. Crop rotation must adapt to the farm’s production system, resources, and labor.
Principles of crop rotation
The ideal crop types must be chosen in order to implement a successful crop rotation. The following is a list of general principles that are considered to assist in crop selection for rotation:
- The rotation should comprise a variety of crops, including cover crops, mulch crops, trap crops, cash crops, etc., and diversely classified families.
- Leguminous species should follow non-leguminous species so that legumes can fix atmospheric nitrogen into the soil and increase the amount of organic matter in the soil.
- Shallow-rooted crops should succeed deep-rooted ones. It aids in the efficient use of soil nutrients and water from different soil depths while improving soil structure and drainage capacity. For the physical characteristics of the soil, for instance, the alternate mix of maize and cabbage is a suitable rotation combination.
- Because they serve as alternate hosts for insects, pests, and diseases, closely related species should not be cultivated one after another.
- Weeds have an advantage over slow-growing crops. As a result, they should be planted in a rotation system right after weed-suppressing crops.
- Dicots, which have tap roots, should be planted after crops with fibrous roots (monocots). It promotes uniform usage of soil nutrients.
- Straw crops and leafy crops should be grown alternately. This helps to suppress weed growth.
- Trap crops that are tolerant of soil-borne diseases and parasitic weeds should be planted after the susceptible crops.
Benefits of crop rotation
The sustainability and productivity of the land are both improved by a well-designed crop rotation scheme. It maximizes return on minimal investment while cutting down on chemical costs without compromising soil fertility. The advantages of crop rotation are listed hereafter.
- Crop rotation ameliorates soil fertility as well as its physical qualities. Rhizobia, a type of soil bacteria that fixes nitrogen, can coexist symbiotically with legumes. This symbiotic relationship causes nodules to grow on the plant’s roots, where bacteria may transform atmospheric nitrogen into ammonia that can be used by plant. Likewise, phosphorus and potassium can be drawn up by deep-rooted plants from the depth of the soil profile, making the nutrients available to subsequent shallow-rooted crops.
- Pests are by nature specialized to particular host species or families. For those insects that are immobile, have a limited range of crops to feed on or whose larvae and eggs overwinter in the soil or crop residue, rotating a non-host species might limit their ability to reproduce, grow, and develop
- Introduction of cover crops in the rotation cycle limits requirements of light, space and nutrients for weeds which in turn minimizes the weed population.
- The cultivation of non-host plants can be employed to manage pathogens with limited host ranges, that depend on crop residues for survival during the off-season. This aids in preventing the reproduction of pathogens, hence halting the spread of disease.
- Crop rotation provides more crop remnants and green manure to the soil, supplementing the soil’s organic matter. As minimum tillage is adequate on the plot where crop rotation is practiced, the organic matter of the soil is retained.
- Crop rotation promotes crop diversification as well as microbial activities while producing minimal disturbance to the soil.
- As some crops possess different traits that make them resistant to extreme weather conditions, growing them in rotation decreases the likelihood of crop loss due to unfavorable climate.
- To put it in a nutshell, crop rotation contributes to improving crop productivity by integrating different preceding fold of advantages.