When using a "trench" latrine, what should each user do?

When using a trench latrine, it is essential for each user to leave behind the shovel in order to cover the waste with dirt. This practice is important for maintaining hygiene and preventing the spread of disease, as properly covering waste helps to mitigate odors and makes the environment safer for others. The act of covering waste is a fundamental principle in responsible waste management, particularly in temporary or wilderness settings where sanitation facilities may be limited.

By leaving the shovel at the site for the next user, the system promotes a continuous cycle of cleanliness and respect for the shared space. This ensures that the shovel is readily available for the next person to use, so they can also properly cover their waste. Additionally, the shovel being left in place reduces the risk of it becoming lost or misplaced, which could compromise sanitation efforts for all users.

The other options miss the crucial point of ensuring the next user can uphold sanitation standards effectively.