Ecology and food economy

Cycle of common agricultural products (rice, corn)

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Rice and corn: History, cultivation techniques


Cereals have been a dominant part of our food since farming began.

RizMaisRice is the staple food for a large part of the world's population, and corn has become paramount, particularly in the variant of maize for animal feed.

In this chapter, we are going to review the history and techniques of rice and corn cultivation.


Rice is one of the oldest subsistence food crops. It was first cultivated in Asia 8000 years BCE. Rice is referred to in historical, social and religious documents. Its importance is evident in the fact that, in Oriental languages, the words ‘rice’ and ‘food’ are often synonymous.

Rice was not cultivated in Europe until 320 BCE. The Portuguese and the Spanish brought it to America. Today, rice is grown everywhere, but especially in humid and sunny regions.

There are many varieties of rice, classified according to the size of the grains. It perhaps comes as no surprise that rice with the longest grains is called long-grain rice, some of which is naturally aromatic, such as Basmati rice.


When Christopher Columbus and his crew reached the ‘New World’ in the 15th century, they encountered corn, a plant that was entirely new to them.

Corn as we know it today, did not exist in a natural state. It was the result of numerous selections and the crossbreeding of a wild grass called teosinte, a plant grown as forage in Mexico about 9000 years ago.

Teosinte Mais

Over the years, pre-Columbian civilisations selected the best plants and thus the size of the cobs and the number of kernels per cob gradually increased.

We can probably thank the first selected mutation for the fact that the kernels, when ripe, remain firmly attached to a rigid cob. This facilitates harvesting, but makes corn unable to disseminate by itself.

The second mutation removed the hard protective shell around the teosinte grain. Just like wheat, corn now has a 'naked grain', exposed to insects and fungi, but easier to digest, without having to husk it.

Corn was initially grown in subtropical or tropical climates, but the development of hybrid varieties meant that it can now be planted practically anywhere in the world.

Corn is available in more than 200 varieties throughout the world, classified according to the properties of the kernels: Sweetcorn is either sold on the cob or the kernels are tinned; soft grain flour corn is used to make cornflour or dent corn, which is high in starch.

There are also new varieties of corn that have been genetically modified to improve their resistance to certain pests and herbicides.


Rice is mainly cultivated in one of two ways.

Riz pluvialIrrigated rice cultivation is when rice plants are submersed in water. This is an intensive growing technique and the most efficient form of rice cultivation, and therefore also the most common. Half of the world’s rice-growing areas use this technique and produce about 75% of the world's rice. Irrigated rice cultivation requires costly landscaping to obtain a perfectly flat paddy field and to control the level of water.

Riz irriguéThe remaining 25% comes from rainfed rice cultivation. This is an extensive growing technique, without submersion of the rice plants. Here, the paddy fields are not irrigated but, instead, are watered by rainwater or ground water, and hence require less development. This form of rice farming predominates in areas with limited water resources, in Africa for example. As the yield depends on rainfall, rainfed rice cultivation faces the risk of droughts.

Throughout the world, there are approximately 160 million hectares of land allocated to rice cultivation. This is equivalent to 38 times the surface area of Switzerland.

Asia produces some 90% of the world’s rice, including 30% in China alone.

Riz production

Corn has become a symbol of intensive farming in Western Europe, the US and China, but it is also extensively cultivated in western South Africa, and semi-extensively in Argentina and Eastern Europe.

The total area devoted to growing corn in the world is slightly larger than that of rice, adding up to about 177 million hectares, or 42 times the surface area of Switzerland. The US is the largest producer and devotes around 39 million hectares to farming corn.

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