The Granary/Terrace are critical for the quick growth of cities, as they essentially double cities' growth rate, given enough -producing tiles are available. The whipping mechanic of Slavery essentially constitutes an efficient conversion of Food to Production , at the expense of producing . Additionally, the Granary/Terrace give +1 to grain resources, making it the earliest -multiplying building in the game. Therefore, it is advisable to build Granaries/Terraces in most every city, at some point.
Due to the Granary being such critical infrastructure, the Incan player will be building Terraces in most every city. As the Terrace gives +2 , the Incan player can forgo the Monument to gain early culture and pop out the city radius; this saves valuable early Hammers. As each city gets +2 in the course of normal play, this is effectively equivalent to playing as a Creative leader. Consequently, Huayna Capac can almost be considered as having three traits: Financial, Industrious, and Creative.
Much of the Incan empire was located on the steep slopes of the Andes Mountains. Such terrain posed a significant challenge to agriculture, as constant soil erosion made the ground less fertile, and heavy rains were quite likely to wash away the current crops (as well as the soil they stood on). Very early on, the Incan farmers mastered the art of constructing terraces upon which to grow their crops. These terraces created much flatter ground upon which to farm, which resulted in less soil erosion and greatly increased production.
Creation of farming terraces in such steep terrain required a good deal of engineering skill (to build the necessary retaining walls), as well as an abundance of cheap manual labor and a sophisticated knowledge of irrigation. They were well worth the effort, however, and with them the Incans were able to sustain thriving cities in locations that other civilizations would have found totally inhospitable.