Grain trade

The grain trade refers to the local and international trade in cereals such as wheat, barley, maize, rice, and other food grains. Grain is an important trade item because it is easily stored and transported with limited spoilage, unlike other agricultural products. Healthy grain supply and trade is important to many societies, providing a caloric base for most food systems as well as important role in animal feed for animal agriculture.

The grain trade began as early as agricultural settlement, identified in many of the early cultures that adopted sedentary farming. Major societal changes have been directly connected to the grain trade, such as the fall of the Roman Empire. From the early modern period onward, grain trade has been an important part of colonial expansion and foreign policy. The geopolitical dominance of countries like Australia, the United States, Canada, and the Soviet Union during the 20th century was connected with their status as grain surplus countries.

More recently, international commodity markets have been an important part of the dynamics of food systems and grain pricing. Speculation, as well as other compounding production and supply factors leading up to the 2008 financial crisis, created rapid inflation of grain prices during the 2007–2008 world food price crisis. More recently, the dominance of Ukraine and Russia in grain markets such as wheat meant that the Russian invasion of Ukraine in 2022 caused increased fears of a global food crises in 2022. Changes to agriculture caused by climate change are expected to have cascading effects on global grain markets.

The grain trade is probably nearly as old as grain growing, going back to the Neolithic Revolution (around 9,500 BCE). Wherever there is a scarcity of land (e.g. cities), people must bring in food from outside to sustain themselves, either by force or by trade. However, many farmers throughout history (and today) have operated at the subsistence level, meaning they produce for household needs and have little leftover to trade. The goal for such farmers is not to specialize in one crop and grow a surplus of it, but rather to produce everything their family needs and become self-sufficient. Only in places and eras where production is geared towards producing a surplus for trade (commercial agriculture) does a major grain trade become possible.

In the ancient world, grain regularly flowed from the hinterlands to the cores of great empires: maize in ancient Mexico, rice in ancient China, and wheat and barley in the ancient Near East. With this came improved technologies for storing and transporting grains; the Hebrew Bible makes frequent mention of ancient Egypt's massive grain silos.

Merchant shipping was important for the carriage of grain in the classical period (and continues to be so). A Roman merchant ship could carry a cargo of grain the length of the Mediterranean for the cost of moving the same amount 15 kilometres by land. The large cities of the time could not exist without the supplies delivered. For example, in the first three centuries AD, Rome consumed about 150,000 tons of Egyptian grain each year.

During the classical age, the unification of China, and the pacification of the Mediterranean basin by the Roman Empire created vast regional markets in commodities at either end of Eurasia. The grain supply to the city of Rome was considered to be of the utmost strategic importance to Roman generals and politicians.

In Europe, with the fall of the Roman Empire and the rise of feudalism, many farmers were reduced to a subsistence level, producing only enough to fulfill their obligation to their lord and the Church, with little for themselves, and even less for trading. The little that was traded was moved around locally at regular fairs.