Which outcome directly enabled dense maize cultivation in pre-Columbian chinampa systems?

💡 Explanation

When azolla is cultivated in chinampa canals, nitrogen fixation occurs because symbiotic cyanobacteria within azolla convert atmospheric nitrogen into ammonia, enriching the soil with readily available nitrogen fertilizer, directly supporting maize yields. Therefore nitrogen fixation results, rather than phosphate solubilization, potassium release, or carbon sequestration which provide indirect benefits or address different limiting nutrients.

• Which outcome arises when an astrolabe's alidade is misaligned relative to the horizon ring during solar altitude measurement?
• Which effect limited long section road construction in pre-Roman Europe before 300 BC?
• Which structural failure was a primary risk in Roman castra fortifications during prolonged siege?
• Which outcome affected image clarity in Alhazen's 11th-century experiments on spherical mirrors focusing sunlight?
• Which stabilization method prevented lateral displacement in Roman arched roadways during heavy use?
• Which error increases when an 18th-century navigator fails to account for dip when using a sextant?