Mono-cropping vs multicropping

Same aim but different game

Few decades ago, the Green Revolution worked. Today, we are at the brink of a similar situation where our population is growing, but food production isn’t much. We can’t rely on past successes; it won’t feed our future. We need to revolutionize how we farm. 

A forest ecosystem is very productive and sustainable. It is diverse, sequesters billion metric tones of carbon every year, and harbors all sorts of life dependent on it. Forest soil is rich in carbon and other nutrients. There is an entire ecosystem beneath the land thriving with success. On the other hand, a typical farm has only one type of crop. It does sequester some amount of carbon, but due to our poor management practices, like stubble burning, etc., net carbon uptake is negligible. There isn’t much wildlife that thrives on such an agroecosystem. In fact, one of our objectives while farming is to keep any life, like birds, pests, animals, etc., away from it. Farm soil needs to be managed (by adding fertilizers) to make it suitable to grow a crop.

What makes the forest ecosystem so sustainable? Diversity! We should try to make our farming systems self-sustaining. I spoke about the biogeochemical cycles (nutrient cycle) and pests in my last article. Nutrient depletion in the soil and pest attacks are some of the above-below ground problems our farms are facing. Crop yields are no longer increasing, in fact, they are plateauing or decreasing in some cases. What solutions do we have?

Multicropping is growing two or more types of crops together. These crops are specifically selected so that they only have a positive influence on each other’s growth. In a mono-cropping system, a single crop has similar resource requirements to grow. Hence, soil resources are depleted in a similar way all over the field, and we add fertilizers to balance the depletion. In multicropping, as different crops are present, they have different resource requirements and acquisitions. Their interactions balance the resources in the soil; thus, we need less fertilizer inputs. When it comes to pests, one crop attracts pests, and the other discourages pests. This creates a balance and checks the growth of any pest population. 

Mono-cropping vs multicropping

One such example is the corn-bean system. Corn needs a lot of nitrogen to grow, so it will deplete soil nitrogen during its growth. Once corn is given a head start to grow, beans replenish this nitrogen in the soil. Crop rotation is an alternative to multicropping; it works on a similar principle. Say there are two crops which grow during different periods of the year. Thus, one can be sowed after the other is harvested. What about pests, then? It is important to understand that not all crops have the same types of pests. Corns have shoot fly, beans have aphids. Thus, once corn is harvested, the shoot fly population will have nothing to feed on; hence their population will cease. Same happens to aphids. In a mono-cropping system, when you cultivate the same crop for the next cycle, the existing pest population gets new food to prey on. Multicropping and crop rotation breaks this cycle.

Corn-bean system

Between seasons when no crops are grown, most of the times, the land is left barren throughout, which leads to soil erosion, loss of nutrients, and the soil loses moisture. Growing cover crops during this period will help in avoiding these problems. Cover crops help in nutrient fixation and carbon sequestration to reduce greenhouse gases. Growing cover crops on the land which rather could have left bare is always good for soil health.

Now that we have established a few farming options, let’s bring climate change in the picture. Climate change is the biggest obstacle for future farming. Also, its effects will be more severe in some places than in others. There, introducing new farming practices may not be enough in mitigating food scarcity. We need our crops to be climate resilient too! How can we do that? Plant breeding to the rescue again! If you recall from my first article – Reaping the bread of a revolution, plant breeding played an important role in Green Revolution. We can use a similar technique to breed new varieties of crops which have heat, cold, drought, and flood tolerance. One example of such crops is rice developed by International Rice Research Institute (IRRI), Philippines. Submergence-tolerant rice developed by IRRI scientists can survive severe floods. These varieties can stay underwater for 12-14 days straight and still harvest significant yields avoiding a big loss to the farmer.

To mitigate hunger and climate change, we need to change how we farm, and I know it’s too much to change. Adapting new practices to conserve and manage soil health, and research and introduce new plant varieties which are climate resilient. What if we remove these variables and farm in a completely different way?

Climate-controlled greenhouses. Here, we completely control the growing environment from biotic conditions in soil to abiotic conditions like temperature, precipitation, sunlight, etc. We can even farm soil-less! It’s impossible to control the climate, but we know what optimum conditions our crops need to give high yields. This is exactly what’s done in Climate-controlled Greenhouses. With the use of advanced technology, temperature and precipitation is adjusted in the greenhouse favorable to the crop. It is lit with red and blue light (Fact: Red and Blue wavelengths in the visible light are best for photosynthesis). Many countries like the Netherlands, Singapore are doing this on a large scale and their crop yield is significantly higher.

Greenhouses in the Netherlands

The total area of greenhouses in the Netherlands, a tiny country, is larger than the size of Manhattan.

Thus, increasing our yield by using different farming techniques while making our farming climate smart is vital to mitigate hunger and malnutrition. Food Security is a global issue, but it will impact countries differently. In my next (and the final article of Food Security series), I will talk about the ground level situation and why international collaboration is vital.

 

 

Writer

Rohit Pawar

Rohit is an ecologist who recently graduated with a bachelor’s degree in Biosciences from Savitribai Phule Pune University. He wishes to devote his life to ecosystem conservation. In his free time, he worries and overthinks about the biggest problems in the world, especially climate change. He thinks that we are 4 Elon Musks away from saving this planet.

Illustrator

Dhaval Shejwal

Dhaval Shejwal

Dhaval is currently pursuing his bachelors in Microbiology. Both science and art are his passions. Creativity keeps him going. Scientific data visualization and communication have become the need of time and necessity, as well to break the wall between a lab and home. According to him, “Art is a beautiful reflection of Science, there is art in science and science in art”.

 

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