Why is it ironic that the refugees spent their days harvesting crops?!

What was ironic is the fact that they spent their days harvesting crops that they themselves were not allowed to eat even though they were starving.  

As the workers discovered that the available labour force far exceeded the number of jobs available, there was a significant reduction in pay. Often, even with a whole family at work, they still could not support themselves and were unable to afford even a basic home.

the folsom i believe

the option which was not a function of missionaries in the northwest was the first one - they established posts for trading furs and other goods.

missionaries were sent around the world to spread religion and their knowledge and others - they were not merchants who sold furs and other goods.