Final answer:
The Inca increased their farmland through terrace farming, where flat areas were cut into mountain slopes. This method prevented soil erosion, enabled irrigation, and allowed for diverse crop growth. These terraces, along with a strong community labor system and effective government management of surplus produce, supported a sizable population efficiently.
Step-by-step explanation:
The Inca created more farmland by employing a sophisticated technique known as terrace farming. To combat the difficulties of farming in the steep topography of the Andean mountains, they cut out flat areas, or terraces, into near-vertical mountain slopes. These terraces were formed by creating retaining walls filled with loose stones for drainage, then topping them with soil. This method of terraced agriculture not only maximized arable land but also prevented soil erosion, allowed for irrigation, and created micro-climates to grow diverse crops which were critical to supporting a large population.
The Inca empire's ability to harness the climate and geography of their land was essential to their agricultural success. Crops such as corn, potatoes, beans, coca, and cotton were commonly grown on these terraces. The Inca utilized a community-based labor system known as the ayllu, where groups worked the land together, sharing the yield based on ability and need. This system facilitated the production of enough food to sustain the large population, estimated to be around 12 million inhabitants at the empire's peak.
Furthermore, the Inca government played a central role in managing the surplus produce. Enormous warehouses stored not only food but also other goods such as clothing and tools, which could be distributed to the people during times of need. This infrastructure, alongside their welfare programs, provided a robust safety net for their population. The productivity of Inca agriculture was so effective that some estimates suggest more land was under cultivation then than is the case today, even with modern technology.