Science of Life
Crop Rotation
What is Crop Rotation?
Crop rotation is the process of growing different crop species on the same field to maintain soil fertility and productivity. The opposite of this is what is known as monoculture cropping, and is the main practice used in the summer of South Africa. Monoculture cropping is known to cause disease build-up, reduce nutrients in the soil, and cause deforestation. Contrarily, crop rotation is able to prevent the build-up of pathogens and pests that favour a specific plant type. This results in improved soil health and structure, increasing soil water supply during droughts.
​
Researchers from the ‘South African Journal of Plant and Soil’ Drs Liana Acevedo-Siaca and Peter D. Goldsmith state that soybeans and maize have proven to build a well-sustained agricultural foundation for farms located in westernized populations and suggest that this would stay consistent in the African continent. Maize economically and nutritionally supports African countries, with the biggest maize producers in sub-Saharan Africa being Nigeria, Tanzania, and South Africa. Over twenty-five percent of sub-Saharan Africa’s daily caloric intake comes from maize, sometimes over fifty percent in countries including Lesotho, Zambia, and Malawi. According to a study conducted by Stanford University, maize has gained a high sensitivity to drought even though technological input has provoked an increase in yields. Droughts have the ability to reduce maize production by up to forty percent. When the Southern African nation has continuously been affected by events such as variable rainfall, farmers struggle to grow foods and earn a profit.
​
Threatened economies that rely on agricultural growth and overall sustainability suffer significantly from invasive plant species and weeds. Weeds are known to disrupt crop growth, stealing resources such as nutrients and water, meaning that there is less food for farmers to sell, less food for people reliant on these farming families and smallholders, which therefore leaves farmers in poverty.
​
La Trobe University's Associate Professor of Animal Plant and Soil Sciences Dr Monika Doblin advised encouraging the growth of native plant species. She suggests that in Australia, we should limit the growth of British plant types deriving from the First Fleet and lean towards growing native Australian plants. This could be applied to the developing world. Native plants are not invasive and support the environment; they promote biodiversity, better suit climate conditions and do not contribute to land degradation. Subsequently, growing native crops would be a highly effective way to implement crop rotation, reduce invasive plant growth, and further increase yields.
The advantages of crop rotation - Source: North Carolina State University
​
The Pros and Cons of Crop Rotation
Below is a detailed list of the pros and cons of crop rotation.
Pros of Crop Rotation
Increased soil fertility and soil nutrients: Because each crop type absorbs and releases different types of nutrients, the amount of deficient nutrients is well controlled
Increased crop yield: Due to better soil fertility and an increase in nutrients, the soil is able to provide for all crops and ensures success in the yield.
Reduced soil erosion: When crops cover soil, the topsoil layer will not be washed away by rainfall. A layer of cover crops prevents soil erosion, unlike standalone crops.
Lowered number of pests and diseases: Crop rotation obstructs the life cycle of pests and diseases as similar plants usually contain the same pathogens. Growing host plants in a low infestation season would lower the risk of infestation and reduce the need for pesticide use, which is better for the environment.
Reduced stress of weeds: Crop rotation allows for crops to use up all farm space, absorb all nutrients and reduce the area in which weeds can grow.
Cons of Crop Rotation
Cost: Different crop types will require different equipment to maintain their health.
Risk: Pathogens from infested crops can spread to other crops on a farm.
Requires skill and knowledge on proper execution: Farmers need to be knowledgeable on how each crop is supposed to be grown, harvested, which equipment is needed, etc.
Is Crop Rotation Essential in Developing Countries?
The short answer is, in most cases, yes. Crop rotation is an easy way to increase the health of the soil and from the figure above, you can see that it is easy to switch between two plants and increase yield for both. This is also good as it helps people maintain a more balanced diet which will come with health benefits as well.
​
Crop rotation allows for a farm to become, on average, 15% more efficient for each type of plant. This means that by doing almost nothing except switching between plants every season, you will get 15% more food. When combating the issue of overpopulation, one of the most crucial factors is ensuring high efficiency in food production, and crop rotation increases this efficiency with practically no downsides. Providing education programs to farming communities in sub-Saharan Africa, and South and Southeast Asia would help promote crop rotation in developing countries, and reduce costs for these families. Crop rotation may become more popular and farmers may start to abandon the environmentally destructive nature of monoculture cropping. Although there may be situations where crop rotation is not ideal, especially in urban agriculture, crop rotation is essential in combatting food shortages whilst facing overpopulation.