Typically, equipment used in farming activity for the purpose of producing income is listed in the assets section where it's capitalized and depreciated over time.
If you're taking money from your 401(k) for this and you're not of retirement age yet, you can expect to pay a 10% penalty for the early withdrawal unless the money is used for a qualified exception. (Farming or any other business equipment purchase is not a qualified exception.) Additionally, the withdrawal will be subject to regular income tax regardless of what you use that money for. (assuming it's not a ROTH retirement account of some type).
Without more details about your farming activity, that's the best I can do at this point.
