Per IRS Pub 225 page 79
4-H Club or FFA project.
4-H Club or FFA project.If an individual participates in a 4-H Club or National FFA Organization (FFA) project, any net income received from sales or prizes related to the project may be subject to income tax.
Report the net income as “Other income” on Schedule 1 (Form 1040), line 8. If necessary, attach a statement showing the gross income and expenses.
The net in-come may not be subject to SE tax if the project is primarily for educational purposes and not for profit, and is completed by the individual under the rules and economic restrictions of the sponsoring 4-H or FFA organization. Such a project is generally not considered a trade or business. For information on the filing requirements and other tax information for dependents, see Pub. 929
Enter as "Less Common Income",
Other reportable income
Any Other Taxable Income - YES,
Description - enter "4H or FFA project proceeds after expenses"
Enter - amount
You will need to print and mail the return to attach the income and expense statement..
BTW - that can only go on the child's own tax return - not yours.