• Intercropping

What’s the first thing that comes to mind when you hear the word “intercropping”?

If your answer is something along the lines of “never heard of it” or “is that some kind of avant-garde haircut?” this is the article for you. We’re here to tell you all about the mechanics and potentials of intercropping and why you should care about it.

What Is Intercropping?

So, let’s start at the beginning. Intercropping is the practice of growing two or more crops in the same field. The primary goal of intercropping is to produce the largest potential yield and maximize resource use on a finite amount of land and resources.

Intercropping can be especially helpful for smaller farmers with plots that are just a few hectares or smaller and also for farmers who have difficulty accessing inputs due to location, financial circumstance and other factors.

Why Is It Important?

The International Center for Tropical Agriculture (CIAT) spoke with farmers in Nicaragua, Guatemala and Mexico and found that 67% of farmers interviewed experience between 3 and 8 months of intense food scarcity each year. These months are so ubiquitous that coffee producers in these regions often say “está llegando la epoca de las vacas flacas” meaning, “the time of the skinny cow is arriving. Variously they are known as ‘the lean season’.

Intercropping might be able to help minimise the impact of these lean months. As the population continues to grow, inching up to nearly 8 billion humans on the planet, demands for food and pressure on our natural resources like fresh water and arable land will only grow. Intercropping may prove to be one solution to both greater food demands and lower availability of water and land.

There is a growing body of literature that suggests by most accounts, widespread intercropping may be better at feeding a growing world than the monocultures we have in place in many countries currently. Intercropped fields can often yield more biomass and more calories per hectare than monocropped fields. Diversifying farms means a greater variety of nutrients and more security against crop failure.

The Run Down

With intercropping, a focus on generating the highest potential yield on a plot of land means using crops that complement each other and aid in mutual growth. Complementary plant systems can provide five main services to other plants: increased water access, pest control, shade, live mulching and nitrogen fixing.

More Water Access for All Plants

Plants with shallow root structures often have trouble accessing water sources. However, recent studies have found that when shallow-rooted plants are planted alongside those with deeper root structures, both plants can benefit.

Deeper root structures can tap into water sources further underground and pull water upwards. In doing so, they also inadvertently bring up more water than they need. Scientists have also conjectured that this water lift can carry with it more nutrients, additionally benefitting all plants.

This effect could be so important to future intercropping practices that some researchers are trying to breed plants with a focus on selecting for root structures that bring up more water than they need.

Natural Pest Control

Insects like the coffee borer beetle (CBB) are notorious for the damage they can wreak on coffee plants. Intercropping can minimize or eliminate the need for pesticides by planting specific species that attract other insects like the square-necked grain beetle, which is a natural predator to CBB.

A wide range of plant species can also confuse pests that typically feed on a particular plant. Due to this confusion, pests will often elect to feed and lay eggs in monocropped settings.

Law of the Minimum: More Nutrients = Higher Yield

Plants require many different nutrients, including nitrogen and phosphorous. The nineteenth century German chemist, Justus von Liebig’s Law of the Minimum states that the yield of any plant will be only as big as the potential yield of the most limited nutrient.

The most limited nutrient is often nitrogen. Archaeological evidence suggests that farmers have been using animal manure as a natural fertilizer for over 3,000 years. In 1903, chemists created the first artificial fertilizer. Since then, the field of artificial fertilizers has exploded. Over the past century, we have slowly depleted many natural stores of nitrogen—including the famous Guano Islands in Peru — and have been increasingly relying on oil-based nitrogen products.

Because oil, like all other nonrenewable resources, will eventually also run out, it is important that we maintain and develop our knowledge of natural alternatives to artificial fertilizers. In addition to using animal manure, we can use intercropping and plant more legume species, one of the most well-known nitrogen-fixing plants that leave the soil most nitrogen-rich than before they were planted.

Enriching the Soil

The last two services—shade and live mulching—are interconnected. Both serve to protect and enrich the soil for other plants.

Shade trees on coffee plantations serve to keep ambient temperatures cooler for growing coffee cherry. They also keep the soil cooler, which can slow moisture evaporation. Similarly, live mulching — using plants that do not yield a harvest (such as grasses) — can help keep soil cooler.

Altogether, more plant cover reduces water runoff, which means that more rainwater stays in the soil for plants’ use later. Less runoff also means less pollution in our waterways.

The higher density of plants in an intercropped field also means more competition for resources, and typically, fewer weeds will grow.

Nobody’s Perfect

While intercropping can be a great tool for “sustainable intensification” in agriculture, it can come with drawbacks. The largest downside of intercropping is the increased labor required. Because it’s not uniform, intercropping is typically not suited to mechanization. The associated increase in labor costs could increase costs for coffee.

This need for more labor could also put more pressure on today’s youth to enter farming. With more intercropping, we’d need more farmers and day laborers to plant, nurture and harvest intercropped fields.

Intercropping can also be complicated and require knowledge of how plants grow and the best ways to pair different plants together. If done poorly, with the wrong plants in the wrong environment, nutrients can be drained from the soil and plants can suffer. It can also mean more trial and error—more lean times—before getting it right.

The Future of Farming

Considering the challenges we face with climate change, increasing population and potentially intensified farming, we need more research in intercropping systems.

This is especially evident when looking at plant breeding. The goals for selective breeding for monocropping are different than those for intercropping. For monocropping, plants are selected primarily for their ability to grow in their environment as efficiently as possible. Environmental preservation can sometimes come as an afterthought.

On the other hand, breeding plants for intercropping centers around the interaction of plant species. Plants are selected based on the ability of their traits to work well with another plant and to preserve the environment for all the future plants that may be grown on that land.

As we move forward in this uncertain age, options are invaluable. Regardless of whether intercropping is or is not fitted to become the predominant form of agriculture, a better understanding of how to pair crop species and maximize yields with smaller inputs can be an important tool to have in the face of these changes.

This article was written by Victoria Brown, Content Marketer.  

 

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