I read a lot of articles and blogs online, and nothing seems as universally rejected as Monoculture. In this post, I want to summarize the scientific consensus on Monoculture to get a better and unbiased picture of this vital topic. All claims I make in this post will be backed up by Studies; I’ll link to all sources at the end of this article. First, I’ll provide a short answer to the main questions, but please go ahead and read the whole article to get a thorough understanding of this complex topic.
How does continuous monoculture affect the soil? Long-term Monoculture depletes the soil, leads to soil erosion, and the destruction of biodiversity. It’s a system build on the benefits of short term gain and causes tremendous damage in the long run.
Before I go into the effects of Monoculture I first want to define what it actually is. Going forward I’ll use the following definition whenever I talk about Monoculture.
What is Monoculture
Monoculture describes the practice of growing only a single crop (or keeping one species of animals) on a large area of land1. Some notable examples are Wheat, Soy, and Corn. Monoculture is used both in commercial as well as organic farming.
For the sake of this article, I’ll focus on Monocropping, i.e., practicing Monoculture for an extended time (covering multiple growing seasons). These two terms often get used synonymously, but they don’t have the same meaning. The opposite of Monoculture is Polyculture, meaning growing multiple different types of plants in the same field. Whereas, the Opposite of Monocropping is Crop-Rotation. So technically, the title of the post is wrong; I am not talking about the practice of Monoculture. But the misuse of the term “Monoculture” is so widespread that it replaced the word Mono-cropping almost entirely.
With the definition out of the way, let’s look at the effect of Monocropping (positive or negative) on the soil?
How does Monocropping affect the soil
Monocropping is detrimental to soil health in the long run. Continuous Monoculture led to the fastest depletion of soil nutrients, compared to other methods of growing Vegetables2. A Studie from 20193 also noted a decrease in soil organic matter, soil structure, and an increased need for fertilizers, as well as more water contamination, compared to crop-rotation. Another issue arises from stored carbon levels in the soil, during Monoculture less carbon can be stored and retained it the soil4.
The most significant effect of Monoculture on the soil is the depletion of certain nutrients. It’s important to remember; different plants require different nutrients. These plants would naturally grow in harmony, helping to establish a balance of Minerals in the soil. Monoculture prevents this harmony. Hence the nutrients drained from the ground always stay the same. Low levels of certain Minerals (like nitrogen and phosphorus) reduce the expected yield5. To combat this issue, fertilizers are used, however not all the Minerals in the fertilizer are needed; any excess will lead to imbalances in the soil. At this point, water can easily wash away these Minerals. This pollution is a huge problem; Later I’ll go into more detail.
Microorganisms in the soil are also affected by Monocropping practices. This study6 observed a reduction of the diversity of Bacteria in the ground. We still lack a clear understanding of the role Bacteria plays in plant growth, but this study also suggests a connection between plant development and microbial communities.
I couldn’t find a single study reporting improved soil health after implementing a Monocropping system. There was one Study talking about better soil quality in Monoculture, but it only compared different types of fertilizers.7
Next, I want to take a look at the effect of Monoculture practices on soil structure.
Does Monocropping cause Soil erosion
Long-term Monoculture deteriorates organic matter levels and soil physical properties. These results lead to accelerated erosion losses and impeded drainage. According to this study8, Monocropping to be a risk factor for soil erosion. Soil runoff was only observed to be higher in bare soil plots9. This study10 compared the soil loss of barren land, monocropping and intercropping, and concluded that the most soil (within cropped plots) was lost in Monoculture.
Is Monocropping the cause of Soil erosion? No, it’s not. It plays a considerable role and contributes to the issue, but doesn’t per se cause it. Natural vegetation is the best option when it comes to soil stabilization 11. Different types of roots help to hold the soil in place and prevent soil runoff. Problems start to arise when land is cleared of natural vegetation to produce growing plots. Monocropping by definition can’t establish a diversity of root systems. To get to the point, its possible to reduce soil erosion with Monocropping on an otherwise bare plot. Clearing natural Vegetation, to establish a Monoculture, on the other hand, is detrimental to soil stability and leads to erosion.
In another post, I did go into more detail on erosion and prevention possibilities.
Monocropping and Biodiversity
I first want to make a clear distinction; I will focus on Monocropping specifically. The arguments I make in this section might also apply to some other commercial farming practices, but this is not the point of this segment.
Biodiversity is a massive issue in Monoculture because this system centers around a single plant species. Often natural Vegetation is removed to establish a new Monocropping plot. The destruction of natural Habitat and Vegetation is devastating to local Biodiversity.5 We already touched upon soil imbalances caused by a lack of diversity, but that’s not the only problem with this system.
Diseases spread rapidly in Monocultures because of limited genetic diversity.12 I recently covered Tomato Blight. This fungus-like disease can decimate whole fields in a matter of days. It’s important to remember that nature functions as a system. Often farmers not only remove the natural vegetation but also plant a genetically homogenous batch of seeds. Reducing plant diversity to an absolute minimum will, in turn, reduce the variety of the Microbiome6, which increases the need for Pesticides to prevent outbreaks.
Pesticides in Monocropping
Pesticides are essential in Monocropping fields. The low Biodiversity and lack of predators attract large numbers of pests, endangering the survival of the crop. To combat this issue, pesticides are used regularly. A study13 published in Nature evaluated the importance of plant trait variance and herbivore performance. It suggests that variability in plant nutrients is crucial to reduce the impact of pests naturally.
Another Study 14 compared pest populations in wheat and cotton Monocultures. The conclusion: The type of plant also plays a role; some crops are better at dealing with pests naturally than others.
Pesticide-free growing is possible but (currently) only feasible in smaller operations. On a large scale, pesticide-use is almost inevitable and used as insurance. The damage will be devastating if a pest or disease gets the upper hand in a monoculture. The whole field will likely die off, and the harvest will be reduced to a minimum.
Often the use of pesticides leads to unwanted side-effects. Application of strong Insecticides will kill not only the targeted pests but also beneficial insects living nearby.15 I wrote an in-depth article about pollinators in vegetable gardens, in which I also touch on the use of insecticides.
The impact of pesticides on human health is also essential to consider. This studies16 compared sprayed and non-sprayed Avena sativa fields by analyzing plant material. A significant weight difference and traces of the pesticide were found in the plants 71 days after spraying. On day 114, the difference was no longer statistically significant.
Another issue arises long-term, pests that survive the onslaught of chemicals will reproduce. Thus they will evolve a natural immunity to the pesticides used in those fields. Stronger chemicals might keep them at bay for now, but at one point, we simply can’t increase the potency or amount of pesticides.17
How does Monocropping affect the Ecosystem
Long-term Monoculture is devastating for the ecosystem. This farming system removes natural vegetation and diversity and replaces it with a single crop. To prevent the plants from dying, vast quantities of fertilizers and pesticides are used. Soil quality and structure suffer considerably, making them both unusable in the long run. Furthermore, the runoff will degrade groundwater, nearby vegetation, and insect populations.
In short, Monocropping is a sure-fire way to destroy natural habitat for short term production. It’s not sustainable and forces an unnatural growing environment. The soil will start to regenerate naturally after monoculture practices cease to exist, but it takes a long time to reestablish vegetation and soil quality.
Studies18,19 observing the health of growing environments concluded a mixture of vegetation is essential for healthy growth. This is true regardless of the type of plant, although some might be more sensitive than others.
Let’s look at the efficiency of monocropping is in terms of yield.
Is Monocropping efficient
Papers on the productivity of intercropping compared to Monocropping are very inconsistent. A study20 set out to examine the productivity of maize/cowpea production in mixed cropping, intercropping, monocropping, and rotation cropping in a timeframe of 4 years. This field study showed that the intercropping system fared the worst followed by sole cropping, and the maize/cowpea rotation showing the highest productivity.
Another Study21 reported a similar yield of the main crop in both intercropping and Monocropping. It’s hard to balance the productivity of Monoculture with other farming practices. Variability in Weather, Soil quality, and plant health make it almost impossible to get a fair comparison.
All in all, it’s probably fair to consider Monocropping similar in productivity to other commercial farming methods.
That begs the question: Why are there still monocropping farms today?
Looking at the Advantages of Monocropping
The Advantages of Monoculture boils down into three main points. It’s cost-efficient, simple to implement/learn, and gives control over the vegetation.
Simplicity: Monocropping is a rather simple agriculture practice. There is no need to learn the intricacies of different plants, soil quality, or insect-household. Soil preparation, basic irrigation, pesticide application, and harvest provides the foundation of Monoculture. Nothing besides the crop is from importance; the only goal of Monoculture is to improve the productivity of the plants grown.
Cost-efficient: Farmers can save lots of money on equipment because they only need machinery to grow and harvest a single type of crop. It’s also cheaper to optimize growing conditions. Growing different plants requires diversity in Minerals and climate. Adjusting a plot to suit one specific plant is both more affordable and manageable.
Plant control: Monocultures are not part of a natural ecosystem. Undesirable Organism (vegetation/pests) can be killed with pesticides, leaving only the profitable crops behind. Furthermore, Monocultures can specialize in lucrative crops to maximize profit.
What are the risks of Monocropping
Let’s also summarize the risks of Monocropping.
Destruction of the soil: Monoculture will deplete soil nutrients and destroy soil structure in the long run. Making it vulnerable to erosion and almost uninhabitable for natural vegetation once the farm ceases to operate. Fields are abandoned once they reached their limit, this means more natural vegetation will be cleared to continue production.
Pollution of groundwater: Excess Minerals from fertilization and Chemicals from Pesticides can be washed into the groundwater. This will endanger both the people living close to a big Monoculture plot but also nearby natural Vegetation. Monocropping practices are not only devastating to the used area but also to everything that surrounds it.
Destroys natural Biodiversity: Monoculture and natural Vegetation don’t work together. Destruction of local Biodiversity takes a long time to regenerate. In some cases, it’s impossible to heal without human interference due to lasting damage to the soil’s structure.
One big question remains, should we use Monoculture to produce our food or not?
Should we use Monocropping
Quick disclaimer this section is my personal opinion, please proceed with caution!
I honestly believe Monocropping should not be used, no matter the short term benefits. I understand that Monocultures are essential for small farmers in poor regions of the world. I also acknowledge the benefits of this practice and the rewards it gives us. Without the use of Monocropping modern Agriculture wouldn’t be the same. Prices for fresh foodstuff and esp. animal products would rise (significantly), and our modern Lifestyle of faster, cheaper and better might need some reworking.
Alternatives to Monocropping
Here, I am going to look at viable alternatives for improvements in commercial Monoculture practices. The information presented is based on this Study22.
Improving the existing System: Improving or replacing toxic chemicals and fertilizers with less pollutant and energy-consuming alternatives can help to make the current system more sustainable. For example, N-Fertilizers can be replaced with N-binding plants (like legumes), and chemical pesticides can be supplemented with bio-pesticides. Crop-rotation and cover-cropping are two ways to improve soil nutrients naturally.
Developing a sustainable agriculture system: We need to build an economically viable and sustainable agriculture system. There is no cookie-cutter solution to this issue; it’s a constant quest to improve. One focus point could be Biodiversity to improve nutrient cycling, disease control, and soil structure. This can be achieved with intercropping, crop rotation,
agroforestry, composting, and green manuring. Enhancing pest management by combining multiple (biological, physical, genetic, and cultural) control measures can also help to reduce the impact of large-scale agriculture. There is no right answer to this question; we have to experiment and figure out what works and what doesn’t along the way.
Rethinking Food-Production: Does our food has to be free of imperfections? Should the price really be the most important factor when buying food? Improving food production is crucial for our future, but we should also spend some time rethinking what really matters when it comes to the food we eat.
What are some examples of Monocultures? Monocultures can be found all around the world. Rice, corn, wheat, cotton, soy, or almonds are some things that come to mind. Other less obvious examples are grapes, bamboo, trees (in managed forests), and pastures (livestock).
Thanks for reading through the whole article. I really appreciate you taking so much time to learn about this vital issue. Have a great day!
I accessed all these papers between the 19.-21. April 2020, I had full access to all the studies linked below.
1 Cambrige Dictianory – Monocropping
2Ecological Society of America – Tropical Soil Fertility Changes Under Monocultures and Successional Communities of Different Structure
3Academic Press – Organic Farming Practices: Integrated Culture Versus Monoculture
4NRC Research Institute – Changes in soil carbon under long-term maize in
monoculture and legume-based rotation
5Field Crops Research – Crop yields, soil fertility and phosphorus fractions in response to long-term fertilization under the rice monoculture system on a calcareous soil
6Springer – Soil microbial communities in cucumber monoculture and rotation systems and their feedback effects on cucumber seedling growth
7European Journal of Soil Biology – The application of vegetable, fruit and garden waste (VFG) compost in addition to cattle slurry in a silage maize monoculture: Effects on soil fauna and yield
8NRC Research Institute – Long-range effects of intensive cultivation and monoculture on the quality of southern Ontario soils
9FAO – oil and nutrient losses through sediment under wheat mono cropping and barley legume intercropping from upland sloping soil
10Pakistan Journal of Agricultural Research – Soil and nutrient losses by water erosion under mono-cropping and legume inter-cropping on sloping land
11Restoration Ecology – Can the Study of Natural Vegetation Succession Assist in the Control of Soil Erosion on Abandoned Croplands on the Loess Plateau, China
12Frontiers in Plant Science – Exploitation of Diversity within Crops—the Key to Disease Tolerance
13Nature – Variability in plant nutrients reduces insect herbivore performance
14Agriculture, Ecosystems & Environment – The extent of monoculture and its effects on insect pest populations with particular reference to wheat and cotton
15Australasian Journal of Ecotoxicology – Risks of pesticide use in aquatic ecosystems adjacent to mixed vegetable and monocrop growing areas in Thailand
16The American Midland Naturalist – Pesticide Effects on Decomposition and Recycling of Avena Litter in a Monoculture Ecosystem
17Monoculture in America: a system that needs more diversity
18Forest Ecology and Management – Tamm Review: On the strength of evidence when comparing ecosystem functions of mixtures with monocultures
19Global Ecology and Conservation – Mixed-species versus monocultures in plantation forestry: Development, benefits, ecosystem services and perspectives for the future
20Journal of Agronomy and Crop Science – Yields and Land‐Use Efficiency of Maize‐Cowpea Crop Rotation in Comparison to Mixed and Monocropping on an Alfisol in Northern Ghana
21Journal of Biology, Agriculture and Healthcare – A Review on the Comparative Advantages of Intercropping to Mono-Cropping System
22Sustainable Agriculture – Agronomy for Sustainable Agriculture: A Review