Final answer:
The heritage element preserved in the excerpt from 'My Lord Bag of Rice' is the cultural tradition of rice cultivation and its significance in Japanese society.
Step-by-step explanation:
The heritage element preserved in the excerpt from 'My Lord Bag of Rice' is the cultural tradition of rice cultivation and its significance in Japanese society. The passage mentions the importance of rice in the economy, rituals, and mythology of Japan. It also highlights how imperial Buddhism and the need for labor contributed to the adoption and promotion of rice cultivation in Japan. This excerpt provides insights into the cultural and historical significance of rice in Japan's heritage.