Where can I see the total cost of farm materials and workers used in a crop production?

The total cost of farm materials can be found by selecting "Analyze" → "Reports" in the navigation bar, clicking the "Economics" section, and choosing from several different reports: 

• The "Cost per task" report will allow you to view the cost of workers and materials used during different tasks, which you can filter based on the task category, specific farm material, or worker.
• The "Season costs" report, grouped by "Item," will show you your real production costs, which you can view in general by setting cost type to "total, or narrow down to specific costs such as  individual workers or materials by selecting the relevant cost type.