Corn, Global Crops, and the Atlantic Slave Trade (Lecture Notes)

Seven key global food crops and their global significance

• The seven most important global food crops today:
  • Wheat, Rice, Corn (Maize), Potatoes, Barley, Sweet potatoes, Cassava.
  • Four of these crops originate in the Americas: Corn, Potatoes, Sweet potatoes, Cassava.
  • These seven crops supply at least half of the nutrients consumed worldwide. In particular, they provide at least $rac{1}{2} ext{ of global nutrients}$.
• The scale of global crop wealth (historical context used in lecture):
  • In 1980, the annual value of American crops was circa $200{,}000{,}000{,}000$ (about $2 imes 10^{11}$) dollars.
  • This annual value was probably higher than the value of all precious metals exported from the Iberian colonies over the entire colonial period.
• Growth and population context: maintenance foods vs staples
  • Maintenance foods (a term used by Spaniards in the talk) refer to foods that provide a large share of daily calories; staples are foods that form the backbone of diets.
  • Since the eighteenth century, there has been massive global population growth in part due to the dissemination of these crops (corn, potatoes, etc.).
• The “scope” of corn among these crops
  • Of the seven crops, four are from the Americas (corn, potatoes, sweet potatoes, cassava).
  • More than a third of the world’s food, whether fresh or processed, comes from American-origin plants.
  • Corn, in particular, is grown in about 50 countries across six continents.
  • Among the top ten corn-producing countries, only four are located in the Americas.
• Ecological and agronomic notes about corn
  • Corn is an extremely productive plant: one kernel can yield 100–200 kernels under favorable conditions.
  • Corn grows very fast: harvest can occur in as little as about 50 days in some places; in many regions, it reaches harvest in 3–4 months.
  • It is an excellent harvester of sunlight due to a large leaf surface area, and it can be grown with relatively little water given strong sun and warm nights; cold is detrimental.
  • It is largely a tropical or subtropical plant in terms of preferred conditions but can adapt to diverse environments.
  • There are about at least 25 corn races identified by specialists, with hundreds of varieties overall (genetic diversity is a key asset for breeding).
• Corn’s uses beyond eating direct kernels
  • Corn can be used to produce alcoholic beverages and other food products (e.g., corn-based foods).
  • It serves as fodder for cattle (corn-fed beef is a major component of the global meat supply).
  • It is pervasive in processed foods and beverages (corn is a common ingredient in many products and is present in sweeteners and sodas; it appears in “almost everything” in modern food systems).
  • Industrial uses (e.g., production of materials like rubber-related production via different plant derivatives) are noted in historical contexts.
• Corn and its historical significance for population growth and industry
  • The spread and adoption of maintenance/staple crops such as corn helped drive population growth in various regions, notably in Asia, Latin America, and Africa, contributing to broader demographic and economic shifts.

Corn biology and its rapid productivity

• Corn as a grass-like plant
  • Corn looks like a large version of a grass with a tall stalk and broad leaf spread.
• Life cycle and growth form
  • It is an annual plant: it completes its life cycle within a year, flowering and producing seeds and then dying within that cycle.
  • Its rapid growth and seed production allow many harvests within a single growing season in favorable climates.
• Structural and environmental traits that enable versatility
  • High leaf area enables efficient solar capture and photosynthesis.
  • Tolerance to hot, sunny conditions and relatively low water requirements under optimal conditions.
  • Sensitivity to cold; cold nights or cool climates can limit growth.
• Comparison with wheat (as discussed in class)
  • Wheat requires longer growing periods and more labor; planted in fall and harvested the following year in many regions.
  • Corn reaches harvest more quickly (e.g., ~50 days in some places) and can outperform wheat in many tropical/subtropical contexts.
• Practical implications for labor and production
  • Corn’s rapid growth and high yield per area make it a highly productive staple relative to many other staples like wheat.
• Uses and ubiquity in modern economies
  • Corn’s ubiquity is driven by its versatility in food, feed, and industrial applications; it is embedded in many processed foods and in livestock agriculture.

The seven crops and global nutrient share; relationship to global food systems

• The seven crops provide at least half of global nutrients and calories, with four of them originating in the Americas (corn, potatoes, sweet potatoes, cassava).
• Four key observations about corn’s global role:
  • Corn is grown on every inhabited continent and in many climates, illustrating its adaptability.
  • The crop has a high yield potential (100–200 kernels per kernel) and a short growing cycle under favorable conditions, enabling rapid production.
  • Corn’s presence in processed foods and as animal feed amplifies its impact on global nutrition and economy.
  • The crop’s spread correlates with historical waves of population growth and economic development, including shifts during the Atlantic era.

The Atlantic world, slavery, and the role of corn

• Defining Atlantic slavery versus generic slavery
  • Atlantic world slavery refers to a specific transatlantic system spanning Africa, the Caribbean, the Americas, and Europe, emerging in a capitalist context.
  • Pre-Atlantic slavery existed in many places and times but was generally more localized, less tied to economic exploitation, and not racialized.
  • Atlantic slavery was racialized, with skin color becoming a defining criterion for enslavement and social status.
• Three major differences between pre-1450 slavery and Atlantic slavery
  • Scale: Atlantic slavery expanded dramatically and became economically integrated with global capitalism.
  • Geography: Atlantic slavery was a transoceanic system connecting multiple continents rather than a local phenomenon.
  • Race: Enslavement in the Atlantic era increasingly tied to race, unlike many earlier forms of slavery.
• Why the Portuguese initiated African slave trade before the Americas
  • Exploration of a sea route to Asia (not via overland routes) led to expanding Atlantic exploration starting in the mid-15th century.
  • Portuguese traders established slave trading posts on the West African coast beginning in 1445.
  • Early hubs included Elmina (and other forts in places like Madeira, Cape Verde, Sao Tome, and Principe) used to cultivate and transport enslaved people.
• The Canary Islands and Madeira as early nodes in Atlantic commodity networks
  • Madeira (a Portuguese sugar colony) and other Atlantic islands became sites for provisioning and labor needs, including enslaved labor for sugar cultivation.
• The Great Circuit (the triangle trade) and the centrality of corn in provisioning
  • The Great Circuit (often described as the triangle trade) involved three legs:
  • Liverpool (an 18th-century major port) shipped manufactured goods (e.g., guns) to West Africa.
  • West African trading posts exchanged enslaved people for those goods and other commodities.
  • The Middle Passage carried enslaved people to the Americas, where they labored on plantations producing sugar, cotton, and other commodities; ships returned to Europe with goods produced by enslaved labor.
  • The price dynamics: the price of European trade goods exchanged for enslaved people tended to double in the trade network, reflecting supply and demand dynamics and financing of the slave economy.
• Why corn became central in Atlantic slavery
  • Corn became the principal food of the Atlantic slave trade by the 17th century due to its high yields, short growing cycle, compatibility with West African agricultural practices, and its compact, durable form suitable for transport and long storage.
  • Quantitative snapshot (historical scale):
  • By the 17th century, each slave ship crossing the Atlantic required at least $13 ext{ tons of corn}$ for the transatlantic leg, with voyages typically around $45 ext{ days}$ and carrying about $250 ext{ enslaved people}$, with a daily corn ration of about $ext{2 pounds per person}$.
  • This provisioning implied that to sustain the slave trade, roughly $4.0 imes 10^{4}$ such voyages were needed (i.e., about 40,000 voyages) to transport the mass of enslaved people to the Americas.
  • In the 18th century, around 300 ships departed per year, requiring roughly $11{,}000 ext{ tons}$ of corn annually to meet demands.
  • Why corn specifically in West Africa and the Americas?
  • Corn has a high yield per area and short growing cycle relative to sorghum or millet, making it well-suited to economies transitioning to cash-crop agriculture and to provisioning long ocean voyages.
  • It is adaptable to existing agricultural practices in West Africa and is relatively dense and storable, aiding long shipments and storage aboard ships.
• The historical context of corn’s initial introduction to Africa
  • The Portuguese are believed to have introduced corn to Africa not long after initial contact between Europe and the Americas (roughly within the first forty years of the Columbian Exchange).
  • The spread of corn across Africa was facilitated by provisioning needs of European colonial networks and the suitability of corn to African agro-ecologies, eventually making it a staple in many regions by the 18th–19th centuries.
• The broader implications for capitalism and global history
  • From the mid-15th century onward, enslaved labor and transatlantic commodity networks became foundational to the development of modern capitalism.
  • The slave trade and Corn’s provisioning role illustrate how agricultural crops became embedded in global trade circuits and the brutal labor systems that sustained them.
• Final takeaway from the lecture on corn and slavery
  • The question of whether the slave trade would have existed without corn is nuanced: the evidence presented emphasizes that the Atlantic slave trade began prior to corn becoming central as a provisioning crop, i.e., it began without relying on corn. However, corn later became a crucial staple that sustained and scaled the slave economy through the provisioning of long voyages and labor forces.

Key numbers to remember (quick reference)

• Global crop value (circa 1980): $200{,}000{,}000{,}000$ dollars.
• Africans trafficked to the Americas:
  • Approximately $10{,}000{,}000$ people between the mid-15th and 19th centuries.
• Corn in the Great Circuit ( provisioning quantities )
  • Each slave ship: at least $13 ext{ tons of corn}$ for the transatlantic leg; voyage duration about $45 ext{ days}$; average of $250$ enslaved per ship; daily corn ration ~$2 ext{ lb per person}$.
  • Estimated number of such provisioning voyages:
  • Roughly $4.0 imes 10^{4}$ voyages needed to support the slave trade.
• Atlantic slave trade annual provisioning (18th century): approximately $11{,}000 ext{ tons of corn}$ per year.
• Corn’s agricultural yield: one kernel can yield between $100$ and $200$ kernels.
• Harvest cycle length: roughly $50 ext{ days}$ in favorable areas; often $3-4 ext{ months}$ for harvest elsewhere.
• Global crop diversity (corn races): at least $ext{25 races}$ identified by specialists.
• Countries on continents growing corn: $50 ext{ countries on } 6 ext{ continents}.$