Which agricultural outcome critically depended on the 'milpa' system of companion planting with maize in Mesoamerica?

💡 Explanation

In the milpa system (intercropping maize with beans and squash), beans fix atmospheric nitrogen via symbiotic bacteria in their root nodules, enriching the soil and benefiting the maize. Therefore, soil nitrogen fixation resulted, enhancing maize yields, rather than disease resistance, reduced irrigation, or transport which each stem from other separate mechanisms.

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