A student dependent's unearned income is taxed at the parent's marginal tax rate (the "kiddie tax").
Apparently you have entered your landscaping income as unearned income. Since you have a 1099-NEC, instead of a W-2, that income should be entered as self employment income (schedule C). That will classify it as earned income and you standard deduction will be enough that none of it will be subject to income tax.
But you will be subject to "self employment" tax (SET). SET is how the self employed pay their social security and Medicare tax (about 14%)
