Crop production and the planet

Hi, my name is Dan Bebber from the Department of Biosciences. Have you ever considered the origins of the plants we rely on for food? Before agriculture, our ancestors spent much of their time gathering wild plants to eat. These were rarely nutritious, because they evolved to protect their proteins or oil rich seeds, or starchy roots using hard shells, spines or poisons. Wild fruits, on the other hand, were often rich in sugars, to attract seed disperses. Then, around 10,000 years ago in the Middle East, people started saving and planting the best, largest seeds from a variety of plants. This artificial selection resulted in nice, big, starchy seeds and other properties, that made the plants easier to harvest and grow.

This process is called domestication, and led to the first crops, which in this region were wheat, oats, barley, lentils, apples, pears and figs. People in other parts of the world began domesticating other plants. The Mediterranean gave us wheat, too, along with olives, peas, cabbages and lettuce. Rice, soybeans, onions, peaches and apricots came from China. Central America gave us maize, beans, and sweet potato, while South America yielded potatoes, tomatoes and peppers. The Russian scientist, Nikoli Vavilov, identified 12 centers of origin for crop plants around the world, where wild relatives of our crop species can still be found. The domestication of food plants meant that more food could be obtained with less effort, and the consequences for human societies were huge.

People began to settle in one place, rather than migrating to find food. This led to the first permanent dwellings, villages and towns. More abundant food meant that some people could become farmers, while others specialized in other jobs, like wood workers, metalworkers, priests and rulers. Writing developed, to keep track of what crops and livestock had been produced, and how much had been given up to taxation. Many of the earliest writings from ancient Babylonians and Sumaria relate to agricultural produce. The importance of agricultural seasons for planting and harvesting crops also drove the development of calendars. A long term consequence of the division of labor that resulted from settled agriculture is the inequality in wealth we see in the modern society.

Recent research has shown that the greater the level of agricultural surplus a society produces, the greater its level of inequality. Another consequence is that the diversity of diets declined dramatically. Hunter gatherer societies rely on hundreds of different plant species, whereas a modern Western diet is dominated by fewer than a dozen. Not only does this reduce our nutritional diversity, but makes our food systems vulnerable to shocks, such as extreme weather events or crop diseases. The growth of agriculture quickly led to environmental damage. Populations grew and people cleared more and more land for crops. More land was deforested, and repeated planting of crops damaged soils. Today, agriculture is the largest land use by area, taking up 40% of the available land surface.

Forests have been halved in area since the early 1900s. This has devastated natural ecosystems and biodiversity, and released huge quantities of carbon to the atmosphere that was once locked up inside trees. Crops are often grown in areas with the wrong climates for those crops, requiring irrigation from rivers, lakes or underground aquifers. Over-reliance on irrigation has caused soils to become too salty in many dry regions, and has emptied important bodies of freshwater, like the Aral Sea. Today, global production is dominated by only a few crops. The major grain crops, wheat, rice and maize, make up around half of the food energy consumed by humans, though it varies dramatically.

In many regions, consumption of energy rich foods is very high, while people in many other countries suffer malnutrition. The dominance of the major grains was driven largely by the Green Revolution of the 1960s, when modern plant breeding and the development of artificial fertilizers and pesticides pushed yields ever higher. Overuse of these chemicals has polluted water bodies and caused massive declines in the populations of vulnerable wildlife species. There is particular concern over insects, and the many species of birds and mammals that feed on them. A central question in improving the sustainability of the global food system is how we can grow enough crops to feed everyone healthily, and at the same time protect our soils, water resources, ecosystems, biodiversity and climate.

To do this, we need a clear understanding of crop production around the world, and for this we need data. You’ll find out more in this week’s activity.